Tag: Cholesterol

For Younger Women, High Blood Pressure May Carry Heightened Risks

Women, but not men, with even mildly elevated blood pressure in their early 40s were at increased risk for later heart disease and early death.

High blood pressure in younger people may be particularly hazardous for women, a new study suggests. The study found that women — but not men — with even mildly elevated blood pressure in their early 40s may be at substantially increased risk for later coronary disease and death.

In 1992, Norwegian researchers began studying 12,329 men and women whose average age was 41. They tracked their blood pressure and cardiovascular health for an average of 16 years.

At the start, high blood pressure was much less common in women than in men: 25 percent of women and 35 percent of men had stage 1 hypertension, which the American Heart Association defines as a reading of 130/80 to 139/89. (A reading under 120/80 is considered normal.) Fourteen percent of women and 31 percent of men had stage 2 hypertension, defined as 140/90 or higher. The women also had fewer risk factors for heart disease: They tended to have lower B.M.I.s and lower cholesterol levels, and fewer of them were smokers.

During the follow-up period, 1.4 percent of the women and 5.7 percent of the men had been hospitalized with or died from cardiovascular disease.

Compared with women who had normal blood pressure at the start of the study, those with stage 1 hypertension had more than double the risk of heart disease. In men, this association was statistically insignificant. The study, in the European Journal of Preventive Cardiology, controlled for diabetes, B.M.I., cholesterol, smoking and physical activity.

The authors acknowledge that the study had limitations. It was done in a small geographic area in Norway, and the subjects were primarily Caucasian. Moreover, the researchers had no information about hypertension treatment or the use of cholesterol-lowering drugs during the follow-up period.

Still, “the emerging evidence is that hypertension is worse for female hearts than for male hearts,” said the lead author, Dr. Ester Kringeland, an internal medicine specialist at the University of Bergen in Norway, “and the risk starts at a lower blood pressure level in women.”

Dr. Joyce M. Oen-Hsiao, an assistant professor of medicine at Yale who was not involved in the work, said, “It’s a well-designed study. Most of us just look at risk factors, and we never really break it down by gender. That’s the novelty of this paper — that there’s a statistical difference between men and women. And if we can replicate this finding in our more diverse population, it will change primary prevention.”

Current American Heart Association guidelines say that in otherwise healthy people, high blood pressure up to 130/80 can usually be managed with lifestyle changes. For readings from 130/80 to 139/89, the group recommends antihypertensive drugs, but only for people with other cardiovascular disease risk factors. At 140/90 or higher, medication is indicated in almost all cases. But the guidelines make no distinction between men and women.

Dr. Kringeland said that one reading, or a reading with a home blood pressure monitor, is not enough to make a diagnosis. “A doctor has to take three readings, then average the last two. And to diagnose hypertension, you need at least two visits to the doctor.”

The question of whether a healthy woman in her 40s with a reading of 130/80 should be treated with antihypertensive drugs is still not settled.

“In some women — those with diabetes, for example — treatment is indicated even at this level,” Dr. Kringeland said. “But in women who are otherwise healthy? We don’t have the answer yet. Blood pressure medicines have side effects, and you have to look at the risk-benefit ratio. We need more research about cardiac disease in women.”

The Best Time of Day to Exercise for Metabolic Health

Late-day exercise had unique benefits for cholesterol levels and blood sugar control, a study of overweight men eating a high-fat diet found.

Evening exercise may be more potent than morning workouts for improving metabolic health, according to a helpful new study of exercise timing. The study, which looked at high-fat diets and overweight men, found that late-day workouts moderated the undesirable health effects of a greasy diet, while morning exercise did not.

The study involved only men who were eating a fatty diet, but adds to growing evidence that exercise timing matters and, for many of us, working out later might have particular advantages.

Although we may be only dimly aware of this, operations inside our bodies follow busy, intricate and mutable circadian schedules. All of our tissues contain molecular clocks that coordinate biological systems, prompting our blood sugar to rise and dip throughout the day, along with our hunger, heart rates, body temperature, sleepiness, gene expression, muscle strength, cell division, energy expenditure and other processes.

The full workings of these internal clocks remain mysterious. But scientists know they recalibrate themselves, based on complex cues from inside and outside of our bodies. Most obviously, they synchronize to light and sleep. But they also set themselves by meals, meaning that when we eat, as well as what we eat, may influence our health and metabolism.

Most researchers believe exercise timing likewise tunes internal clocks. But the results of relevant past studies have been inconsistent. Some suggest morning workouts, before breakfast, incinerate more fat than evening exercise. Others find the opposite. And some recent experiments indicate that early exercise, if it is intense, actually impairs blood-sugar control, while the same workouts, performed later, smooth blood-sugar spikes and improve metabolic health, which may have particular benefits for heart health and controlling Type 2 diabetes.

Most of those studies, though, focused on one type of exercise and rarely controlled people’s meals during the experiments, making it difficult to tease apart the effects of exercise timing from those of what and when people eat.

So, for the new study, which was published in May in Diabetologia, scientists affiliated with the Mary MacKillop Institute for Health Research at Australian Catholic University in Fitzroy, Australia, and other institutions, set out to control people’s diets while tinkering with their workout timing.

They began by recruiting 24 sedentary, overweight Australian men (not including women to avoid issues related to women’s menstrual cycles). The scientists invited these volunteers to the lab, checked their aerobic fitness, cholesterol, blood-sugar control and other aspects of health, asked about current eating habits, and then set them up with meal deliveries.

The meals consisted of about 65 percent fat, since the researchers wished to learn how exercise timing might affect fat metabolism, as well as blood-sugar control. The volunteers ate the unctuous foods, and nothing else, for five days and visited the lab for more tests. Then the scientists divided them into three groups. One would start exercising every day at 6:30 a.m., another at 6:30 p.m., and the last would remain sedentary, as a control.

The exercise routines were identical, intermingling brief, intense intervals on stationary bicycles one day with easier, longer workouts the next. The exercisers worked out for five consecutive days, while continuing the high-fat diet. Afterward, the researchers repeated the original tests.

The results were somewhat disturbing. After the first five days of fatty eating, the men’s cholesterol had climbed, especially their LDL, the unhealthiest type. Their blood also contained altered levels of certain molecules related to metabolic and cardiovascular problems, with the changes suggesting greater risks for heart disease.

Early-morning exercise, meanwhile, did little to mitigate those effects. The a.m. exercisers showed the same heightened cholesterol and worrisome molecular patterns in their blood as the control group.

Evening exercise, on the other hand, lessened the worst impacts of the poor diet. The late-day exercisers showed lower cholesterol levels after the five workouts, as well as improved patterns of molecules related to cardiovascular health in their bloodstreams. They also, somewhat surprisingly, developed better blood-sugar control during the nights after their workouts, while they slept, than either of the other groups.

The upshot of these findings is that “the evening exercise reversed or lowered some of the changes” that accompanied the high-fat diet, says Trine Moholdt, an exercise scientist at the Norwegian University of Science and Technology, who led the study in Australia as a visiting researcher. “Morning exercise did not.”

This study does not tell us how or why the later workouts were more effective in improving metabolic health, but Dr. Moholdt suspects they have greater impacts on molecular clocks and gene expression than morning exertions. She and her colleagues hope to investigate those issues in future studies, and also look at the effects of exercise timing among women and older people, as well as the interplay of exercise timing and sleep.

For now, though, she cautions that this study does not in any way suggest that morning workouts aren’t good for us. The men who exercised became more aerobically fit, she says, whatever the timing of their exercise. “I know people know this,” she says, “but any exercise is better than not exercising.” Working out later in the day, however, may have unique benefits for improving fat metabolism and blood-sugar control, particularly if you are eating a diet high in fat.