Tagged Heart

Weight Has Greater Impact on Diabetes Than Heart Disease

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Carrying excess weight may have a greater impact on the risk for diabetes than it does on the risk for heart disease or early death, a new study has found.

To look at the effect of obesity independent of genetics, Swedish researchers followed 4,046 pairs of identical twins whose average age was 58. One of the twins was overweight, and the other was not. Since identical twins have the same genes, their weight difference could not be attributed to genetics. The study is in JAMA Internal Medicine.

After accounting for physical activity, smoking and educational level, the researchers found that having a higher body mass index, or B.M.I. — even among those in the obese range of 30 or higher — was not associated with an increased risk for heart attack or death. But a high B.M.I. was associated with an increased risk for diabetes.

“Based on these results, the association between obesity and cardiovascular disease is explained by genetic, not environmental, factors,” said the lead author, Peter Nordstrom, a professor of geriatric medicine at Umea University. “Unfortunately, this also means that environmental factors that reduce obesity do not reduce the risk of cardiovascular disease or death. But they most certainly decrease the risk for diabetes.”

Rediscovering the Kitchen, and Other Tips for Heart Health

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Credit Paul Rogers

First the bad news: After decades of major progress in reducing deaths from diseases of the heart and blood vessels, the decline in cardiovascular mortality has slowed significantly, according to the latest report from the Centers for Disease Control and Prevention. The researchers called their findings alarming, suggesting that cardiovascular benefits from medical interventions may have reached a saturation point and that further improvements depend largely on changes in society and personal behavior.

The new data, published in June in JAMA Cardiology, covered the years from 2000 through 2014. From 2000 through 2010, the annual rates of decline for all cardiovascular deaths heart diseases and stroke averaged 3.69 percent for men and 3.98 percent for women. But since 2011, the rates of decline dropped to a mere 0.23 percent for men and 1.17 percent for women.

These findings point to near stagnation in controlling cardiovascular diseases and deaths, Dr. Stephen Sidney and colleagues wrote. And, they noted, the reasons are not difficult to discern. Based on data from the latest National Health and Nutrition Examination Survey in 2011-12, Americans did better in controlling three major risk factors smoking, high blood pressure and elevated cholesterol, often with the help of medication but many more people became obese and developed Type 2 diabetes.

According to data from the survey, the prevalence of adult obesity rose from 22.9 percent in 1988-1994 to 34.9 percent in 2011-12, and the C.D.C. found that the prevalence of diabetes nearly tripled, from 2.5 percent in 1990 to 7.2 percent in 2013.

Furthermore, the national survey showed, the percentage of adults who in 2012 were consuming an ideal diet that could minimize life-threatening damage to blood vessels was near zero.

Its not that these grim data were unexpected. Four years ago, Dr. Richard J. Jackson, a professor and former chairman of environmental health sciences at the University of California, Los Angeles, predicted that the current generation of young Americans (those born since 1980) may be the first to live shorter lives than their parents.

Even earlier, in 2007, Dr. Earl S. Ford of the C.D.C. and Dr. Simon Capewell of the University of Liverpool wrote that unless measures were taken to transform the abhorrent risk factor profile that currently characterizes much of the U.S. population and dangerous trends were reversed, mortality rates among younger adults may represent the leading edge of a brewing storm.

Now for the good news: Neither medical innovations nor genetic interventions are needed to turn the tide on cardiovascular diseases and deaths and restore their once-significant declines. And the very same changes needed to improve cardiovascular health may also help prevent many common cancers, diabetes, arthritis, cognitive decline, depression and osteoporosis.

Dr. Donald M. Lloyd-Jones, a chief architect of a 2010 strategic plan to improve cardiovascular health, said: The whole may be greater than the sum of the parts. We shouldnt assume that chronic diseases automatically occur with aging. Living healthfully until we die is an achievable goal.

Dr. Lloyd-Jones, a cardiologist and preventive medicine specialist at the Northwestern University Feinberg School of Medicine in Chicago, chaired an American Heart Association committee of experts that adopted the recommended changes. Instead of focusing on the negative, the plan aims to achieve ideal cardiovascular health through ideal health behaviors and ideal health factors.

Heres how the committee defined ideal: No smoking; maintaining a body mass index below 25; being physically active; following current dietary guidelines; and maintaining an untreated total cholesterol level of less than 200 milligrams, an untreated blood pressure level of less than 120 over 80, and a fasting blood glucose level of less than 100 milligrams.

The committee had hoped that fostering these seven health behaviors and targets would, by 2020, improve the cardiovascular health of all Americans by 20 percent while reducing deaths from cardiovascular diseases and stroke by 20 percent.

But current trends project at best a 6 percent improvement.

Although most of us are born with the potential for ideal cardiovascular health, fewer than half of all adolescents have retained five or more of the seven behaviors and factors at ideal levels, Dr. Lloyd-Jones wrote in 2014. And things get progressively worse with age until ideal cardiovascular health becomes rare above age 60, he said.

Still, he has not given up hope for a better result.

Now for the details. First and foremost, quit smoking or never start. Heart risks drop significantly within a year of quitting and eventually reach those of a nonsmoker.

Next, get regular physical exercise, at least 150 minutes a week of moderate physical activity or 75 minutes a week of vigorous activity, or a combination of the two. Keep in mind that this is the minimum amount of physical activity needed to glean health benefits. More is better.

Exercise should be part of your daily routine, like brushing your teeth. I do a combination of moderate and vigorous exercise every day. It energizes me and helps me control my weight without having to watch every calorie.

As for diet, the committee recommended focusing on foods, not nutrients. (As Dr. Lloyd-Jones put it, We dont eat nutrients.) It refrained from suggesting how many calories people should eat, since caloric needs vary tremendously based on an individuals basal metabolic rate, body size, lean body mass and physical activity.

Rather, it suggested a version of the DASH diet (for Dietary Approaches to Stop Hypertension) that was successfully tested by the National Heart, Lung and Blood Institute. It calls for four and a half or more cups of fruits and vegetables a day; two or more 3.5-ounce servings of fish each week; three ounces of fiber-rich whole grains a day; at most 36 ounces of sugar-sweetened drinks (less than 450 calories, or the equivalent in other sweets) a week; four or more weekly servings of nuts, legumes and seeds; and no more than two servings a week of processed meats.

At the same time, limit saturated fats to less than 7 percent of total calories and daily sodium to 1,500 milligrams for people with high blood pressure and no more than 2,300 milligrams (or one teaspoon of salt) for everyone else. Currently, Americans consume an average of 3,500 milligrams of sodium a day, most of it from processed and restaurant foods.

Which brings me to a final recommendation of my own: Rediscover your kitchen. No matter how busy you are, finding time to prepare healthy foods for yourself and your family should be a top priority.

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Being Unfit May Be Almost as Bad for You as Smoking

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Being out of shape could be more harmful to health and longevity than most people expect, according to a new, long-term study of middle-aged men. The study finds that poor physical fitness may be second only to smoking as a risk factor for premature death.

It is not news that aerobic capacity can influence lifespan. Many past epidemiological studies have found that people with low physical fitness tend to be at high risk of premature death. Conversely, people with robust aerobic capacity are likely to have long lives.

But most of those studies followed people for about 10 to 20 years, which is a lengthy period of time for science but nowhere near most of our actual lifespans. Some of those studies also enrolled people who already were elderly or infirm, making it difficult to extrapolate the findings to younger, healthier people.

So for the new study, which was published this week in the European Journal of Preventive Cardiology, researchers from the University of Gothenburg in Sweden and other institutions turned to an impressively large and long-term database of information about Swedish men.

The data set, prosaically named the Study of Men Born in 1913, involved exactly that. In 1963, almost 1,000 healthy 50-year-old men in Gothenburg who had been born in 1913 agreed to be studied for the rest of their lives, in order to help scientists better understand lifetime risks for disease, especially heart disease.

The men completed baseline health testing in 1963, including measures of their blood pressure, weight and cholesterol, and whether they exercised and smoked. Four years later, when the volunteers were 54, some underwent more extensive testing, including an exercise stress test designed to precisely determine their maximum aerobic capacity, or VO2 max. Using the results, the scientists developed a mathematical formula that allowed them to estimate the aerobic capacity of the rest of the participants.

Aerobic capacity is an interesting measure for scientists to study, because it is affected by both genetics and lifestyle. Some portion of our VO2 max is innate; we inherit it from our parents. But much of our endurance capacity is determined by our lifestyle. Being sedentary lowers VO2 max, as does being overweight. Exercise raises it.

Among this group of middle-aged men, aerobic capacities ranged from slight to impressively high, and generally reflected the men’s self-reported exercise habits. Men who said that they seldom worked out tended to have a low VO2 max. (Because VO2 max is more objective than self-reports about exercise, the researchers focused on it.)

To determine what impact fitness might have on lifespan, the scientists grouped the men into three categories: those with low, medium or high aerobic capacity at age 54.

Then they followed the men for almost 50 years. During that time, the surviving volunteers completed follow-up health testing about once each decade. The scientists also tracked deaths among the men, based on a national registry.

Then they compared the risk of relatively early death to a variety of health parameters, particularly each man’s VO2 max, blood pressure, cholesterol profile and history of smoking. (They did not include body weight as a separate measure, because it was indirectly reflected by VO2 max.)

Not surprisingly, smoking had the greatest impact on lifespan. It substantially shortened lives.

But low aerobic capacity wasn’t far behind. The men in the group with the lowest VO2 max had a 21 percent higher risk of dying prematurely than those with middling aerobic capacity, and about a 42 percent higher risk of early death than the men who were the most fit.

Poor fitness turned out to be unhealthier even than high blood pressure or poor cholesterol profiles, the researchers found. Highly fit men with elevated blood pressure or relatively unhealthy cholesterol profiles tended to live longer than out-of-shape men with good blood pressure and cholesterol levels.

Of course, this study found links between poor fitness and shortened lifespans. It cannot prove that one caused the other, or explain how VO2 max might affect lifespan. However, the findings raise the possibility, as the scientists speculate, that by strengthening the body, better fitness may lower the risk of a variety of chronic diseases.

This study also involved men — and Swedish men at that. So whether the findings are applicable to other people, particularly women, is uncertain.

But “there is no reason not to think” that the rest of us would also share any beneficial associations between fitness and longevity, said Per Ladenvall, a researcher at the Sahlgrenska Academy at the University of Gothenburg, who led the study. Past studies involving women have found such links, he said.

Encouragingly, if you now are concerned about the state of your particular aerobic capacity, you most likely can increase it just by getting up and moving. “Even small amounts of physical activity,” Dr. Ladenvall said, “may have positive effects on fitness.”

Can Statins Cause Diabetes?

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Credit Stuart Bradford

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Cutting Sugar Rapidly Improves Heart Health Markers

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Obese children who cut sugar from their diets saw improvements in markers of heart disease after just nine days, a study in Atherosclerosis found.

For the study, researchers evaluated 37 children ages 9 to 18 who were obese and at high risk for heart disease and Type 2 diabetes. The children were given food and drinks totaling the same number of calories, fat, protein and carbohydrates as their typical diets.

The only change was their sugar intake: The researchers swapped foods high in added sugars, like pastries and sweetened yogurts, for options like bagels and pizza. This lowered dietary sugar from 28 percent to 10 percent, and fructose from 12 percent to 4 percent of total calories.

After nine days, the researchers found a 33 percent drop in triglycerides, a type of fat tied to heart disease; a 49 percent reduction in a protein called apoC-III that is tied to high triglyceride levels; and dramatic reductions in small, dense LDL cholesterol, a risk factor for heart disease.

Though this study is small and short-term, it builds on this group’s previous research implicating added sugars as a contributor to metabolic disorders and heart disease.

“Sugar calories are not like other carbohydrate calories,” said Dr. Robert Lustig, a co-author of the study and professor of pediatrics at Benioff Children’s Hospital at the University of California, San Francisco. “Without changing total carbohydrate, or fat, or protein, we were able to accomplish this enormous improvement in their cardiovascular risk factors,” unrelated to weight loss, he said.

Ask Well: Exercising on ‘Smog Alert’ Days

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Smog hangs over New York City in 1966.

Smog hangs over New York City in 1966.Credit Neal Boenzi/The New York Times

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The Surprising Health Benefits of an Electric Bike

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In the Tour de France, equipping your bike with a small electric motor is called mechanical doping, and is considered cheating. But for the rest of us, an electrified bicycle might be a way to make exercise both tolerable and practical, according to an encouraging new study of bicycle commuting.

Exercise is necessary in our lives, as we all know by now. People who are physically active are much less likely than sedentary people to develop heart disease, diabetes, cancer, stroke, depression, disabilities in old age, or to die prematurely.

But statistics show that, despite its benefits, a majority of us never exercise. When researchers ask why, most people offer the same two excuses — they don’t have time to fit exercise into their lives or they aren’t fit enough to undertake exercise.

Potentially, electric bicycles could address those concerns. Their motors shore up your pedaling as needed—or, with some electric bikes, do the pedaling for you—making climbing hills or riding for long distances less taxing and daunting than the same ride on a standard bicycle.

In the process, they could make cycling a palatable alternative to commuting by car, allowing people with jammed daily schedules to work out while getting to work.

But the value of electric bicycles has so far been mostly notional. Few of us have seen, let alone ridden, an electric bike and there is scant scientific evidence supporting—or refuting—the potential health benefits of using the machines.

So for the new experiment, which was published last month in the European Journal of Applied Physiology, researchers at the University of Colorado, Boulder, decided to see what would happen if they gave a group of out-of-shape men and women zippy electric bikes and suggested that they begin riding to work.

Notably, the researchers only studied motorized bikes that assist the rider rather than doing all the work for them, like a moped. They used electric bikes that require the rider to pedal in order to receive assistance from the motor.

The researchers wanted to determine whether these bikes — even with the added assistance of a motor — would provide a meaningful workout for people who previously had not been exercising much. They also wanted to see whether such bikes were fundamentally safe, given that they enable even novice riders to achieve speeds of 20 miles per hour or higher. (The Boulder city government partially funded the study as part of an assessment of whether to allow electric bikes on municipal bike paths. Additional funding came from local bike shops and Skratch Labs, a sports nutrition company in Boulder.)

The researchers first brought their 20 sedentary volunteers into the lab to check their body composition, aerobic fitness, blood sugar control, blood pressure and cholesterol profiles. Then they provided each with an electric bicycle, heart rate monitor, GPS device, instructions on the use of all of this equipment, and asked each volunteer to don the monitors and ride his or her new bike to and from work at least three times a week for the next month, spending at least 40 minutes in the saddle on those days.

The volunteers were directed to choose whatever speed and effort felt comfortable for them.

Then the researchers loosed the novice riders onto Boulder’s roads and bike paths.

A month later, the volunteers returned to the lab to repeat the original tests and turn over heart rate and GPS data. All of them had ridden at least the prescribed minimum of 40 minutes three times per week and in fact, according to their monitor data, most had ridden more than required, several about 50 percent more.

The riders also had ridden with some intensity. Their heart rates averaged about 75 percent of each person’s maximum, meaning that even with the motor assist, they were getting a moderate workout, comparable to brisk walking or an easy jog.

But thankfully none had crashed and hurt themselves (or anyone else). In fact, “we found that participants rode at a reasonable average speed of about 12 miles per hour,” said James Peterman, a graduate student at U.C. Boulder who led the study.

Perhaps most important, the riders were healthier and more fit now, with significantly greater aerobic fitness, better blood sugar control, and, as a group, a trend toward less body fat.

They also reported finding the riding to “be a blast,” said William Byrnes, the study’s senior author and director of the university’s Applied Exercise Science Laboratory. “It’s exercise that is fun.”

Several participants have bought electric bikes since the study ended, he said. He also rides an electric bike to and from campus.

Electric bikes are unlikely to be a solution for everyone who is pressed for time or reluctant to exercise, though. The bikes are pricey, typically retailing for thousands of dollars.

They also offer less of a workout than non-motorized bicycles. Mr. Peterman, an accomplished bike racer who placed fifth in the time trial at the United States National Cycling Championships last week admits that motorized bicycles are unlikely to goose the fitness of well-trained athletes.

But for the many other people who currently do not exercise or have never considered bike commuting, there is much to be said for knowing that, if needed, you can get a little help pedaling up that next hill.

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Ask Well: Is Watermelon Good for You?

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Credit Karsten Moran for The New York Times

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A-Fib Is More Dangerous for Blacks Than Whites

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Atrial fibrillation, or A-fib, an irregular heartbeat associated with various types of cardiovascular problems, is more dangerous, and more often fatal, in black people than in whites, a new study has found.

Researchers studied 15,080 people, average age 54, of whom 3,831 were black. They followed them for an average of 20 years. The findings were published in JAMA Cardiology.

The rate of atrial fibrillation was higher among whites than blacks, and both white and black people with A-fib had increased risks of stroke, heart failure and coronary heart disease. Those with A-fib also had an increased risk of dying from these and other causes.

But even though rates of A-fib were higher in whites than blacks, the actual effect of A-fib led to much higher rates of disease in blacks than in whites. Compared with white people with A-fib, blacks with the condition were more than twice as likely to have a stroke, 42 percent more likely to go into heart failure, 76 percent more likely to have coronary heart disease, and nearly twice as likely to die prematurely.

The reason for the finding is not clear, but the study had no data on treatment or treatment disparities, which might partly explain the outcomes.

Still, the lead author, Dr. Jared W. Magnani, an associate professor of medicine at the University of Pittsburgh, said that “the extensive health-related differences here are likely fueled by racial disparities. We need a preventive health system for all Americans, and we don’t have that in place.”

Eat Whole Grains, Live Longer?

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Credit Karsten Moran for The New York Times

Two large review studies have reached the same conclusion: Eating whole grains is associated with significant reductions in the risk for premature death.

One report, in BMJ, found that whole grain consumption was associated with a reduction in the risk for death from cancer, coronary heart disease, respiratory disease, infectious disease and diabetes. Using data from 45 studies, researchers calculated that compared with eating none, eating 90 grams of whole grains a day reduced the risk for all-cause mortality by 17 percent.

The other analysis, in Circulation, used data from 14 prospective studies with 786,076 participants and found that compared with those who ate the least whole grain foods, those who ate the most had a 16 percent reduced risk for all-cause mortality and an 18 percent reduced risk for cardiovascular mortality. Each 16-gram increase in whole grain intake reduced mortality risk by 7 percent.

A slice of 100 percent whole grain bread contains about 16 grams of whole grains, and current dietary guidelines recommend 48 grams or more of whole grains daily.

The senior author of the Circulation study, Dr. Qi Sun, an assistant professor of nutrition at Harvard, cautions that eating whole grains is not a panacea.

“You shouldn’t hope that you will cure diseases with whole grain foods,” he said. “You still have to pay attention to other good dietary and behavioral practices.”

Churchgoers May Live Longer

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St. Patrick’s Cathedral in Manhattan.

St. Patrick’s Cathedral in Manhattan.Credit Chang W. Lee/The New York Times

Going to church may lower the risk for premature death, a new study suggests.

Researchers used data from a long-term study of 75,534 women that tracked their health and lifestyle, including their attendance at religious services, over 16 years through 2012. The report is in JAMA Internal Medicine.

After controlling for more than two dozen factors, they found that compared with those who never went to church, going more than once a week was associated with a 33 percent lower risk for death from any cause, attending once a week with a 26 percent lower risk, and going less than once a week a 13 percent lowered risk. Risks for mortality from cardiovascular disease and cancer followed a similar pattern.

The researchers statistically eliminated the possibility of reverse causation — that is, that healthy people go to church more than unhealthy ones. And they found that some variables, such as social support and a tendency not to smoke, contributed to the effect. But no matter how they analyzed the data, the effect of church attendance alone seemed to have benefits.

“This suggests that there is something powerful about the communal religious experience,” said the senior author, Tyler J. VanderWeele, a professor of epidemiology at Harvard. “These are systems of thought and practice shaped over millennia, and they are powerful.”

Migraines Tied to Increased Risk of Heart Problems

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Women who suffer from migraines are at higher risk of developing cardiovascular disease than women who aren’t plagued by the severe headaches, and they are more likely to have a stroke, heart attack or to die of heart disease, a new study reports.

The report, published in BMJ, is an analysis from the Nurses Health Study II, a Harvard study that tracked 115,541 women aged 25 to 42, from 1989 through June 2011. At the study start, 15 percent said they had migraines.

Over the course of two decades, 1,329 heart attacks, strokes or other heart events occurred, and 223 women died of heart disease. The researchers adjusted for smoking and other risk factors and found that the migraine sufferers had a 50 percent greater risk of major cardiovascular disease over all.

Women who had migraines were 39 percent more likely to have a heart attack, 62 percent more likely to have a stroke and 73 percent more likely to have other heart problems or to require a procedure like angioplasty. Migraines were also associated with a 37 percent greater risk of dying of heart disease.

The study is not the first one to find an association between migraines and cardiovascular disease. But experts say they are hard-pressed to explain the link and can only advise migraine sufferers to be aware of the risk and pay attention to signs of a possible heart attack or stroke.

A Low-Salt Diet May Be Bad for the Heart

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Credit Tony Cenicola/The New York Times

People with high blood pressure are often told to eat a low-sodium diet. But a diet that’s too low in sodium may actually increase the risk for cardiovascular disease, a review of studies has found.

Current guidelines recommend a daily maximum of 2.3 grams of sodium a day — the amount found in a teaspoon of salt — for most people, and less for the elderly or people with hypertension.

Researchers reviewed four observational studies that included 133,118 people who were followed for an average of four years. The scientists took blood pressure readings, and estimated sodium consumption by urinalysis. The review is in Lancet.

Among 69,559 people without hypertension, consuming more than seven grams of sodium daily did not increase the risk for disease or death, but those who ate less than three grams had a 26 percent increased risk for death or for cardiovascular events like heart disease and stroke, compared with those who consumed four to five grams a day.

In people with high blood pressure, consuming more than seven grams a day increased the risk by 23 percent, but consuming less than three grams increased the risk by 34 percent, compared with those who ate four to five grams a day.

The lead author, Andrew Mente, an epidemiologist at McMaster University in Toronto, said that eating less salt does indeed lower blood pressure.

“But low sodium intake may be harmful,” he added. “It’s important not to rely on blood pressure alone, but rather to look at actual clinical events — heart attack, stroke, mortality.”

Can High-Intensity Exercise Help Me Lose Weight? And Other Questions, Answered

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I recently wrote about a study showing that one minute of intense interval training, tucked into a workout that was, in total, 10 minutes long, produced comparable health and fitness benefits to 45 minutes of more moderate, uninterrupted endurance training.

Readers posted almost 400 comments to the article and flooded the Internet and my inbox with questions and sentiments about extremely short workouts. Given the extent of the response and the astuteness of the questions, I thought I would address some of the issues that arose over and over.

Q. Are high-intensity interval workouts actually better for you than longer, endurance-style workouts — or just shorter?

A. Better is such a subjective word. At the moment, the two types of workouts appear to be largely equivalent to each other in terms of a wide variety of health and fitness benefits.

In the study that I wrote about, “1 Minute of All-Out Exercise May Equal 45 Minutes of Moderate Exertion,” for instance, three months of high-intensity interval training practiced three times per week led to approximately the same improvements in aerobic endurance, insulin resistance and muscular health as far longer sessions of moderate pedaling on a stationary bicycle.

One type of workout was not more beneficial than the other, in other words, but one required much, much less time.

Other studies have generally produced similar results, although, to be honest, the science related to interval training for health purposes and not simply for athletic performance remains scant. An interesting new review of past research to be published in June did conclude that, for overweight and obese children, short sessions of intense intervals may lead to greater improvements in endurance and blood pressure than longer bouts of moderate exercise, although the authors did not discuss how best to get children to complete frequent interval sessions.

The upshot of the available science is that if you currently have the time and inclination to complete long-ish, moderate workouts — if you enjoy running, cycling, swimming, walking or rowing for 30 minutes or more, for instance — by all means, continue.

If, on the other hand, you frequently skip workouts because you feel that you do not have enough time to exercise, then very brief, high-intensity intervals may be ideal for you. They can robustly improve health and fitness without overcrowding schedules.

Q.

What about combining brief high-intensity workouts with longer, endurance workouts?

A.

Alternating high-intensity workouts with endurance-style workouts may yield the greatest health and fitness gains of all.

In a 2014 study, a group of sedentary adults began either a standard endurance-training program, in which they pedaled a bicycle moderately for 30 minutes five times a week, or swapped one of those bike rides for an interval session. All of the participants wound up significantly more aerobically fit after 12 weeks.

But the men and women who had completed one interval session per week had developed slightly more overall endurance than the other volunteers. As a result, they had lowered their risk for premature death by about an additional 18 percent, the study’s authors conclude.

Q.

Do I have to use a stationary bicycle for interval training?

A.

Most recent studies of high-intensity intervals have involved computerized stationary bicycles because scientists can easily monitor the riders’ pace and intensity. But there is nothing magical about the equipment. The key to high-intensity interval training is the intensity, which most of us can gauge either with a heart rate monitor or our own honest judgment.

For moderate exercise, your heart rate typically should be between 70 and 85 percent of your maximum. (I recently wrote about how to determine your individual maximum heart rate.) This intensity would feel like about an 8 on an arduousness scale of 1 to 10.

During an intense interval, however, your heart rate should rise to 90 percent of your maximum heart rate, or above. Think of this as feeling like about a 9.5 on the 10-point scale. You maintain that intensity for only 10 or 20 seconds at a time, however, followed by several minutes of very easy exercise before repeating the intense work.

Almost any type of exercise can be used for interval training, including running up the stairs in your office’s stairwell during your lunch hour, said Martin Gibala, a professor of kinesiology at McMaster University in Hamilton, Ontario, and an expert on intervals. (His book about the science and practical implications of high-intensity interval training will be published in early 2017.)

Q.

Will high-intensity intervals help me to lose weight?

A.

Few studies have yet looked at the long-term effects on body weight of exercising exclusively with high-intensity intervals, although some experiments do hint that high-intensity interval training can reduce body fat, at least in the short term.

In a 2015 study, for example, overweight, out-of-shape men who began either to jog or otherwise exercise moderately for an hour five days per week for six weeks or to complete intensive interval training for a few minutes per week all dropped body fat and about the same percentages of fat, despite very different amounts of exercise. Likewise, a group of women recovering from breast cancer who were assigned either to moderate exercise or brief interval training for three weeks lost comparable amounts of body fat during the study.

But these were small-scale, brief experiments. Whether interval training helps or hinders long-term weight control is still unknown.

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Think Like a Doctor: Sick at the Wedding

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Credit Anna Parini

The Challenge: Can you figure out what is wrong with a 38-year-old man who suffers from fevers, insomnia and night sweats after traveling to the mountains of Colorado to be his brother’s best man?

Every month, the Diagnosis column of The New York Times Magazine asks Well readers to try their hand at solving a real-life medical mystery. Below you will find the story of a 38-year-old marketing executive from the Boston area who suddenly becomes sick when he takes his family to his brother’s destination wedding in the Rockies. Within a day of their arrival, the man begins to feel sick, though the rest of his family feels fine.

As usual, the first reader to offer the correct diagnosis gets a signed copy of my book, “Every Patient Tells a Story,” along with that feeling of satisfaction that comes from solving a difficult but really cool case.

The Patient’s Story

“Either you are getting in the car with me to go back to the hospital, or I’m calling an ambulance,” the woman announced. “It’s totally up to you.”

Her husband, 38 and never sick a day in his life, had been desperately ill for more than a week. He’d just gotten out of the hospital that morning, and after being home for less than 12 hours he was worse than ever. Though she couldn’t bring herself to say it out loud, she was worried he might be dying. And though he didn’t say anything, so was he.

It had started at his brother’s wedding, one of those destination events in the mountains of Colorado. And almost from the moment he stepped off the plane, he’d started to feel awful. His head ached. So did his body. His eyes were puffy, and his whole face looked swollen. He couldn’t eat, and he couldn’t sleep. When he went to bed that first night, he tossed and turned, though he felt exhausted. In the morning, when he dragged himself out of bed, the sheets were soaked with sweat.

Just the Altitude?

At first he wrote it off as altitude sickness. The resort was 11,000 feet above sea level, and he’d never been this high up. Though his wife and the kids felt fine, there were others in the wedding party who were feeling the effects of the altitude as badly as he did. One of the bridesmaids fainted at the rehearsal dinner. And an elderly aunt had to leave before the wedding.

The day of the wedding it snowed – in May. The kids were thrilled. His wife took them sledding. He’d spent the day in bed, trying – mostly unsuccessfully — to get some sleep. That afternoon the wedding service seemed to last forever. The tuxedo felt like a straitjacket. There was a pressure in his chest that made it hard to breathe. But he’d stood at the front of the church, proud to be best man to his younger brother.

After the service, the photographer led them outside, trying to capture the spring blossoms covered with snow that made the setting so extraordinary, and he worked hard to exhibit an enthusiasm he was too sick to feel.

By the time he made it to the dinner reception, his whole body shook with violent chills, and his head was pounding. His collar felt so tight he could hardly swallow. He’d been working on his toast for days, so his wife talked to the D.J. and changed the order of the toasts so that he could give his toast early. After completing it, he made his apologies, went back to the hotel and climbed into bed.

Feeling Worse and Worse

He figured he’d feel better when they got to the lower altitudes of Denver, where they’d arranged to spend their last night. But he didn’t. Even when he traveled back to Boston, down at sea level, he didn’t feel any better. He had some business in the city so was staying at a hotel while his wife took the two kids back to their home, an hour away. She was worried but he reassured her he’d be O.K.

But that night, alone in his hotel room, he felt so bad he began to get scared. If this was altitude sickness, he should be better by now. Everything he read on the Internet said so.

Finally he could take it no more. He went to the front desk and asked for a taxi and went to the closest emergency room, at Massachusetts General Hospital.

An Inflamed Heart

Because of his chest tightness, the doctors at Mass General ordered an EKG. To his surprise, it was abnormal, and he was rushed to the cardiac care unit. He hadn’t had a heart attack; they were sure of that. But something had damaged his heart.

After dozens of tests, the doctors told him he had something called myocarditis, an inflamed heart muscle, though they couldn’t tell him why. For three days they searched for the cause of injured muscle. Myocarditis is often due to a viral infection, but the doctors wanted to make sure they didn’t miss anything treatable.

At the top of their list, they worried that he had picked up some kind of tick-borne infection while in rural Colorado. None of the tests came back positive, but they sent him home to finish up a week of the antibiotic doxycycline, just in case.

You can read the notes from Mass General and the infectious disease specialist here.

Admission Note

Infectious Disease Notes

A Short Trip Home

In the hospital he felt a little better. His chest didn’t hurt, and his heart wasn’t racing. His fever went down. On his way home he felt like he was on the mend. His wife wasn’t so sure. And a couple of hours later, when she looked in on him again, she was frightened by how sick he looked.

He was pale and sweaty – the way he’d been in the mountains. And the shaking and fevers were back. His headache was so bad that he was crying with pain, something she’d never seen before. She called Mass General. The doctor there said that if she was worried she should bring him right back. But the prospect of an hour-long drive seemed daunting. She decided to take him to the local hospital one town over.

So, did he want her to call an ambulance, or should they go by car?

Back to the Hospital

The patient’s wife dropped off the kids at a friend’s house, then drove him to Anna Jaques Hospital in Newburyport, Mass. It was late by the time they arrived and the emergency room was quiet.

Dr. Domenic Martinello knocked at the entrance to their hospital cubicle. The patient’s wife looked up expectantly, her face tight with exhaustion. The patient lay motionless on the stretcher; his eyes were sunken, and his skin hung off his face as if he hadn’t eaten much recently. His voice was soft but raspy, and every time he swallowed, his lips tightened in a grimace of pain.

Together, husband and wife recounted the events of the past few days: the wedding, the fevers, headaches, pain in his chest, in his neck and in his throat, the four days in the hospital in Boston.

It was certainly a confusing picture, and Dr. Martinello wasn’t sure what to make of the diagnosis of myocarditis. But the patient had no chest pain now, only the headache, sore neck and painful throat.

He quickly examined him. The patient’s skin was warm and sweaty, and his neck was stiff and tender, especially on the right. He was going to approach this systematically, he told the couple. First he would get a head CT, then a scan of the neck, and then he would do a lumbar puncture – a spinal tap. He felt optimistic that one of those tests would give him an answer.

You can see Dr. Martinello’s note here.

Hospital Note

Solving the Mystery

Dr. Martinello did get an answer. But it wasn’t the one he was expecting.

The first reader to identify the cause of this man’s illness gets a copy of my book and the pleasure of making a difficult diagnosis. The answer will be posted Friday afternoon on Well.

Rules and Regulations: Post your questions and diagnosis in the comments section below. The winner will be contacted. Reader comments may also appear in a coming issue of The New York Times Magazine.

Loneliness May Be Bad for Your Heart

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Loneliness may make you sick.

Researchers, writing in the journal Heart, pooled data from 23 studies and found that social isolation or feelings of loneliness were tied to an increased risk for coronary heart disease and stroke.

The studies included data from 181,006 men and women 18 and older. There were 4,628 coronary events and 3,002 strokes in follow-up periods ranging from three to 21 years. Three of the papers measured loneliness, 18 looked at social isolation and two included both. Social isolation and loneliness were determined with questionnaires; the researchers depended on medical records and death certificates for determining coronary events and stroke.

The scientists found that loneliness and social isolation increased the relative risk of having a heart attack, angina or a death from heart disease by 29 percent, and the risk of stroke by 32 percent. There were no differences between men and women.

“People have tended to focus from a policy point of view at targeting lonely people to make them more connected,” said the lead author, Nicole K. Valtorta, a research fellow at the University of York in England. “Our study shows that if this is a risk factor, then we should be trying to prevent the risk factor in the first place.”

The authors acknowledge that this was a review of observational studies and did not establish cause and effect.

Higher B.M.I. in Teenagers Tied to Heart Risks Later

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Higher body mass index in adolescence, even in the normal range, is tied to an increased risk for cardiovascular disease in adulthood, according to a new study.

Researchers used data on 2,454,693 Israeli men and women who underwent medical evaluations for military service at age 17 from 1967 through 2010. Over the 40 years of follow-up, there were 2,918 deaths from cardiovascular causes, about half of them from coronary heart disease. The study is in The New England Journal of Medicine.

Compared to 17-year-olds with B.M.I. in the 5th to 24th percentile (corresponding to a median B.M.I. of about 18.9), those in the 25th to 49th percentile (B.M.I. 20.6) had a small increased risk for coronary heart disease in adulthood. But those in the 50th to 74th percentile (B.M.I. 22.2) had a 49 percent increased risk, and those in the 75th to 84th percentile (B.M.I. 24.3) — still normal by current guidelines — had more than double the risk. The study controlled for sex, education, socioeconomic status and other factors.

The lowest risk for death was among those with B.M.I.’s between 18.3 and 19.8, the low end of normal.

“A single study shouldn’t by itself change what is considered to be the normal range,” said the lead author, Dr. Gilad Twig, an internist at the Sheba Medical Center in Israel. “But being overweight in adolescence is bad — we knew that before, and this study shows it’s really bad.”

Childhood Stress Is Linked to Hardening of the Arteries

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Stress in childhood may be linked to hardening of the arteries in adulthood, new research suggests.

Finnish researchers studied 311 children 12 to 18 years old, scoring their levels of stress according to a variety of components, including the family’s economic circumstances, the emotional environment in the home, whether parents engaged in healthy behaviors, stressful events (such as divorce, moves or death of a family member) and parental concerns about the child’s social adjustment. Using these criteria, they calculated a stress score.

When the members of the group were 40 to 46 years old, they used computed tomography to measure coronary artery calcification, a marker of atherosclerosis and a risk factor for cardiovascular disease.

The study, in JAMA Pediatrics, controlled for sex, cholesterol, body mass index and other factors, but still found that the higher the childhood stress score, the greater the risk for coronary artery calcification.

The study is observational, and the data is based largely on parental reports, which can be biased. Still, its long follow-up time and careful control of other variables gives it considerable strength. There are plausible mechanisms for the connection, including stress-induced increases in inflammation, which in animal models have been linked to a variety of ailments.

“I think that economic conditions are important here,” said the lead author, Dr. Markus Juonala, a professor of internal medicine at the University of Turku in Finland. “Public health interventions should focus on how to intervene in better ways with people with higher stress and lower socioeconomic status.”

Few Americans Follow 4 Main Pillars of Heart Health

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Most Americans know that a heart-healthy lifestyle includes eating a healthful diet, not smoking, being physically active and keeping weight and body fat down. But a new study found that fewer than 3 percent of American adults could claim all four healthy elements.

Only 2.7 percent of the Americans in the study were nonsmokers who ate a reasonably good diet, including eating plenty of vegetables and whole grains and avoiding saturated fat; got at least 150 minutes of moderate exercise a week; and had a healthy percentage of body fat, defined as up to 20 percent for men and 30 percent for women.

The results were “shocking,” said Ellen Smit, an associate professor at Oregon State University College of Public Health and Human Sciences and the senior author of the report. “I think it’s a wake-up call.”

The study, published in Mayo Clinic Proceedings, was based on data gathered from the National Health and Nutrition Examination Survey from 2003 to 2006 and included a nationally representative sample of 4,745 Americans.

Eating habits were self-reported, which can be unreliable, but other measures were based on objective tests, including blood samples to verify smoking status, a sophisticated X-ray test to determine body fat, and accelerometers to measure physical activity.

 

The Longer You Work, the Greater Your Risk for Heart Disease

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Credit iStock

The more hours you work, the greater your risk for heart disease.

Several observational studies have found an association of long work hours with an increased risk for cardiovascular illness. Now a new retrospective analysis has found there is a dose-response relationship: more hours, more risk.

Researchers began following 1,926 men and women in 1986, tracking their health and work history through 2011. Over the course of the study, in the Journal of Occupational and Environmental Medicine, 822 were given diagnoses of cardiovascular disease.

After adjusting for age, sex, income and other factors, they found that for each additional hour of work per week over 10 years, there was a 1 percent increase in the risk for heart disease.

Compared with working 45 hours a week, working 55 hours increased the risk by 16 percent, 60 hours by 35 percent, 65 hours by 52 percent, and 70 hours by 74 percent. Working 75 hours or more doubled the risk for a cardiovascular problem — angina, coronary heart disease, hypertension, stroke or heart attack.

Still, the lead author, Sadie H. Conway, an assistant professor at the University of Texas School of Public Health, does not recommend that anyone alter work hours based on her study.

“I would never tell a person ‘don’t work long hours’ because of this risk, but it’s something that shouldn’t be ignored from a public health standpoint.”