Tagged Muscles

Attention, Teenagers: Nobody Really Looks Like That

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Credit Anna Parini

The universal truth of puberty and adolescence is body change, and relatively rapid body change. Teenagers have to cope with all kinds of comparisons, with their peers, with the childhood bodies they leave behind, and with the altered images used in advertising and in the self-advertising on social media.

It may be that the rapid way the body changes during these years can help adolescents believe in other kinds of change, including the false promises that various products can significantly modify their size and shape. A study published last month in the journal Pediatrics looked at two kinds of risky behavior that are increasingly common over adolescence: the use of laxatives for weight loss and the use of muscle-building products.

It used data from an ongoing study of more than 13,000 American children, the Growing Up Today Study (GUTS). The participants’ mothers took part in the Nurses’ Health Study II, and the children were recruited in 1996, when they were 9 to 14 years old, and surveyed about a variety of topics as they grew up.

By age 23 to 25, 10.5 percent of the women in this large sample reported using laxatives in the past year to lose weight; the practice increased over adolescence in the girls, but was virtually absent among the boys. Conversely, by young adulthood, about 12 percent of the men reported use of a muscle-building product in the past year, and again, this increased during adolescence.

So a lot of young women are taking laxatives to try to become very thin, and a lot of young men are using products to help them bulk up and become more muscular. The researchers were interested in how these practices were associated with traditional ideas of masculinity and femininity. They found that, regardless of sexual orientation, kids who described themselves as more gender conforming were more likely to use laxatives (the girls) or muscle-building products (the boys).

“The link is the perception that they are going to alter your weight, shape, appearance,” said Rachel Rodgers, a counseling psychology researcher who studies body image and eating concerns and is an associate professor of applied psychology at Northeastern University.

“The representations of ideal appearance in society are very restrictive and very unrealistic both for men and for women,” she said. “They portray bodies that are unattainable by healthy means.”

Jerel Calzo, a developmental psychologist who is an assistant professor at Harvard Medical School, and the lead author on the study, said that one important aspect of this research was the way it highlighted the vulnerability of those who identify with traditional gender ideals.

“Usually in research we tend to focus on youth who are nonconforming, who we might focus on as more at risk for negative health outcomes, depression, who might be ostracized or victimized,” he said. But there are risks as well for those who are trying to measure up to what they see as the conventional standard.

The GUTS participants were asked to describe themselves as children in terms of the games they liked and the movie and TV characters they imitated, and this was used to score them as more or less “gender conforming.”

The early patterns of gender conformity were significant, Dr. Calzo said, because they were linked to behaviors that lasted through adolescence and into young adulthood. “Laxative use increases with age, muscle-building product use increases with age,” he said. “There is a need for early intervention.”

Chronic use of laxatives can affect the motility of the bowel so that it can be hard to do without them, and overdoses can alter the body’s balance of electrolytes, to a really dangerous extent.

“There’s a lot of shame and guilt for laxative abuse,” said Sara Forman, an adolescent medicine specialist who is the director of the outpatient eating disorders program at Boston Children’s Hospital. And many products marketed as cleanses or herbal teas are not labeled as laxatives, though they contain strong laxative ingredients.

The muscle-building products in the study included steroids, creatine and several others. The risks of steroids are well known, from hormonal imbalances and shrinking testicles to acne and aggression. With other commercial muscle-building products, the risks may have more to do with the lack of regulation, Dr. Calzo said. The products can contain banned substances or analogues of banned substances, like the amphetamine analogue found in popular diet and workout supplements last year.

And of course, the muscle-building products won’t reshape you into the photoshopped model any more than the laxatives will.

As Dr. Calzo says, we need to worry about the vulnerabilities of children who are growing up with issues of gender identity and sexuality. But don’t assume that more “mainstream” or “conforming” kids have it easy when it comes to body image. Parents can help by keeping the lines of communication open and starting these conversations when children are young. We should be talking about the images that our children see, about how real people look and how images are altered.

And that conversation should extend to social media as well; in a review by Dr. Rodgers, increased social media use was correlated with body image worries. “Teenagers are looking at their friends on social media and seeing photos that have been modified and viewing them as something real.”

The other message for parents is about helping to model healthy eating, family meals, realistic moderation around eating and exercising, and to refrain from any kind of negative comments or teasing about a child’s body. “Research has shown people who have more body satisfaction actually take care of themselves better, which suggests that the approach of making them feel bad is actually not helpful,” Dr. Rodgers said.

Every adolescent, across gender, gender identity, gender conformity, and sexuality, lives with a changing body and the need to navigate body image and identity. There are a lot of unrealistic images out there to measure yourself against, and a lot of false promises about how you might get there.

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Can Running Make You Smarter?

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Credit Getty Images

To strengthen your mind, you may first want to exert your leg muscles, according to a sophisticated new experiment involving people, mice and monkeys. The study’s results suggest that long-term endurance exercise such as running can alter muscles in ways that then jump-start changes in the brain, helping to fortify learning and memory.

I often have written about the benefits of exercise for the brain and, in particular, how, when lab rodents or other animals exercise, they create extra neurons in their brains, a process known as neurogenesis. These new cells then cluster in portions of the brain critical for thinking and recollection.

Even more telling, other experiments have found that animals living in cages enlivened with colored toys, flavored varieties of water and other enrichments wind up showing greater neurogenesis than animals in drab, standard cages. But animals given access to running wheels, even if they don’t also have all of the toys and other party-cage extras, develop the most new brain cells of all.

These experiments strongly suggest that while mental stimulation is important for brain health, physical stimulation is even more potent.

But so far scientists have not teased out precisely how physical movement remakes the brain, although all agree that the process is bogglingly complex.

Fascinated by that complexity, researchers at the National Institutes of Health recently began to wonder whether some of the necessary steps might be taking place far from the brain itself, and specifically, in the muscles, which are the body part most affected by exercise. Working muscles contract, burn fuel and pump out a wide variety of proteins and other substances.

The N.I.H. researchers suspected that some of those substances migrated from the muscles into the bloodstream and then to the brain, where they most likely contributed to brain health.

But which substances were involved was largely a mystery.

So for the new study, which was published last month in Cell Metabolism, the N.I.H. researchers first isolated muscle cells from mice in petri dishes and doused them with a peptide that affects cell metabolism in ways that mimic aerobic exercise. In effect, they made the cells think that they were running.

Then, using a technique called mass spectrometry, the scientists analyzed the many chemicals that the muscle cells released after their pseudo-workouts, focusing on those few that can cross the blood-brain barrier.

They zeroed in on one substance in particular, a protein called cathepsin B. The protein is known to help sore muscles recover, in part by helping to clear away cellular debris, but it had not previously been considered part of the chain linking exercise to brain health.

To determine whether cathepsin B might, in fact, be involved in brain health, the researchers added a little of the protein to living neurons in other petri dishes. They found that those brain cells started making more proteins related to neurogenesis.

Cathepsin B also proved to be abundant in the bloodstreams of mice, monkeys and people who took up running, the scientists found. In experiments undertaken in collaboration with colleagues in Germany, the researchers had mice run for several weeks, while rhesus monkeys and young men and women took to treadmills for four months, exercising vigorously about three times a week for approximately an hour or sometimes longer.

During that time, the concentrations of cathepsin B in the jogging animals and people steadily rose, the researchers found, and all of the runners began to perform better on various tests of memory and thinking.

Most striking, in the human volunteers, the men and women whose fitness had increased the most — suggesting that they had run particularly intensely — not only had the highest levels of cathepsin B in their blood but also the most-improved test scores.

Finally, because there’s nothing like removing something from the body to underscore how important it may be, the scientists bred mice without the ability to create cathepsin B, including after exercise. The researchers had those mice and other, normal animals run for a week, then taxed their ability to learn and retain information.

After running, the normal mice learned more rapidly than they had before and also held on to those new memories well. But the animals that could not produce cathepsin B learned haltingly and soon forgot their new skills. Running had not helped them to become smarter.

The lesson of these experiments is that our brains appear to function better when they are awash in cathepsin B and we make more cathepsin B when we exercise, says Henriette van Praag, an investigator at the National Institute on Aging at the N.I.H. who oversaw this study.

Of course, increases in cathepsin B explain only part of the benefits of exercise for the brain, she said. She and her colleagues plan to continue looking for other mechanisms in future studies.

They also hope to learn more about how much exercise is necessary to gain brain benefits. The regimen that the human runners followed in this study was “fairly intensive,” she said, but it’s possible that lighter workouts would be almost as effective.

“There is good reason to think,” she said, “that any amount of exercise is going to be better than none” for brain health.

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Learning to Walk in My 60s

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The author, Jacques Leslie, taking a step.

The author, Jacques Leslie, taking a step.Credit Blink Inc.

I knew about my limp before I knew much else about myself. It was 1951, at the height of the polio epidemic, and I was a 4-year-old in Beverly Hills, Calif. My father took me swimming in the pool of a club where he played tennis. Sometime later, a woman who’d swum in the pool a week or two before me was stricken with polio. A few days after that, while we were on vacation, I began limping and developed a fever.

After a doctor paid a visit to our hotel room and somberly conferred with my parents, they drove me to the Los Angeles County Hospital, where I spent a night or two in a hallway with dozens of other patients because the polio wards were full. For reasons I never grasped, I was sometimes tied to the bed, even though I clearly wasn’t going anywhere. I’d noticed that my right leg was numb, and I could no longer move it.

By the time I got home from the hospital a month later, I could walk, but only a few steps at a time. I remember once collapsing at the top of our staircase and waiting for someone to carry me back to my room. The disease shortened my right leg, partially atrophied my calf muscle, limited my ankle’s flexibility and curled my foot perceptibly inward.

Over the next decade I saw doctors regularly, performed daily exercises supervised by my stern father, and for months at a time wore corrective plaster-of-paris casts intended to twist my foot back toward normalcy. None of this kept me from an active childhood. I loved baseball — I played catcher, of course — and loathed the coach who yelled at me for running slowly, as if I could will speed. I dreaded running laps in phys ed class, where I’d inevitably come in last. Because my balance was poor, I fell down often. And I hated dancing, which seemed to require everything I lacked.

But in some ways polio felt like a distinction. It handed me a knowledge that others didn’t have. It made me serious when most kids around me were anything but. I understood Chester, Marshal Dillon’s sidekick on “Gunsmoke,” who limped his way though television’s longest-running series. I grasped his isolation, his lack of confidence, his compensating insight into everyone else. If I wasn’t already destined to be an observer, polio made certain that I was one, and laid the foundation for my career as a professional observer, a journalist.

By the time I reached adulthood, I more or less forgot about my limp. I spent six years as a foreign correspondent, including two covering the Vietnam War (while I was classified 4-F because of my leg). I zealously exercised and paid no attention to the dipping of my right shoulder each time I put weight on my right leg. If someone asked me about the limp, I’d mention polio and told them I must be tired.

My polio story would have ended there if I hadn’t consulted a physical therapist named Lisa for an unrelated problem a couple of years ago.  “We have to change the way you walk,” was one of the first things she said to me, with an urgency that took me by surprise. I was 67, and the idea of changing my walk struck me as at least a few decades too late, if it had ever been possible at all. “No,” Lisa said. “If you don’t learn to walk properly, the older you get, the more likely you’ll fall down.”

After a close examination of my leg, she stunned me once more: “Your limp is probably unnecessary.” In becoming accustomed to limping as a child, she concluded, I’d sacrificed the tone of healthy muscles, from my abdominals to my toes, that supported walking. If I reawakened them, I’d have enough muscle to achieve a normal stride.

Over the next year and a half, I saw Lisa nearly 50 times. At the beginning of each session, she’d watch me walk, then devise a treatment plan on the spot. She didn’t go for broke, as a previous therapist had: Her approach was gradual and intuitive. The exercises she assigned me were challenging but not overwhelming, and seemed to build upon themselves.

Each day at home I worked with straps, bands, assorted balls and a low tottering platform on which I learned to keep my balance while standing on my right foot — something I’d always considered impossible. As the muscles kicked in, one by one, I realized how I’d maneuvered around their weakness. As I walked, I often held my left my arm slightly behind me, stiffly, as if on call to provide balance. When I sat down, I planted my left foot on the floor and curled my right foot behind it — only my left side was rooted in the ground.

My foot eventually flattened out. The shoulder dip disappeared. Walking stopped feeling like a chore. My daughter said she no longer heard the familiar ker-CHUNK ker-CHUNK of my old gait. My spirits improved. My confidence grew. My writing career even enjoyed an uptick. And why not? For the first time in my life, at nearly 70 years old, I was standing on my own two feet.

A former Los Angeles Times foreign correspondent, Jacques Leslie is the author of “The Mark: A War Correspondent’s Memoir of Vietnam and Cambodia.”

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Exercise Makes Our Muscles Work Better With Age

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Credit Getty Images

To keep our muscles healthy deep into retirement, we may need to start working out more now, according to a new study of world-class octogenarian athletes. The study found substantial differences at a cellular level between the athletes’ muscles and those of less active people.

Muscular health is, of course, essential for successful aging. As young adults, we generally have scads of robust muscle mass. But that situation doesn’t last.

Muscles consist of fibers, each attached to a motor neuron in our spinal column by long, skinny nerve threads called axons. The fiber and its neuron are known as a muscle unit.

When this muscle unit is intact, the neuron sends commands to the muscle fiber to contract. The muscle fiber responds, and your leg, eyelid, pinky finger or other body part moves.

However, motor neurons die as we age, beginning as early as in our 30s, abruptly marooning the attached muscle fiber, leaving it disconnected from the nervous system. In younger people, another neuron can come to the rescue, snaking out a new axon and re-attaching the fiber to the spinal cord

But with each passing decade, we have fewer motor neurons. So some muscle fibers, bereft of their original neuron, do not get another. These fibers wither and die and we lose muscle mass, becoming more frail. This process speeds up substantially once we reach age 60 or so.

Scientists have not known whether the decline in muscular health with age is inevitable or whether it might be slowed or altered.

There have been encouraging hints that exercise changes the trajectory of muscle aging. A 2010 study of recreational runners in their 60s, for instance, found that their leg muscles contained far more intact muscle units than the muscles of sedentary people of the same age.

But whether exercise would continue to protect muscles in people decades older than 60, for whom healthy muscles might be the difference between independence and institutionalization, had never been examined.

So for the new study, which was published last week in the Journal of Applied Physiology, researchers from McGill University in Canada and other schools contacted 29 world-class track and field athletes in their 80s and invited them to the university’s performance lab. They also recruited a separate group of healthy but relatively inactive people of the same age to act as controls.

At the lab, the scientists measured muscle size and then had the athletes and those in the control group complete a simple test of muscular strength and function in which they pressed their right foot against a movable platform as forcefully as possible. While they pressed, the scientists used sensors to track electrical activity within a leg muscle.

Using mathematical formulas involving muscle size and electrical activity, the scientists then determined precisely how many muscle units were alive and functioning in each volunteer’s leg muscle. They also examined the electrical signal plots to see how effectively each motor neuron was communicating with its attached muscle fiber.

Unsurprisingly, the elite masters athletes’ legs were much stronger than the legs of the other volunteers, by an average of about 25 percent. The athletes had about 14 percent more total muscle mass than the control group.

More interesting to the researchers, the athletes also had almost 30 percent more motor units in their leg muscle tissue, and these units were functioning better than those of people in the sedentary group. In the control group, many of the electrical messages from the motor neuron to the muscle showed signs of “jitter and jiggle,” which are actual scientific terms for signals that stutter and degrade before reaching the muscle fiber. Such weak signaling often indicates a motor neuron that is approaching death.

In essence, the sedentary elderly people had fewer motor units in their muscles, and more of the units that remained seemed to be feeling their age than in the athletes’ legs.

The athletes’ leg muscles were much healthier at the cellular level.

“They resembled the muscles of people decades younger,” said Geoffrey Power, who led the study while a graduate student at McGill and is now an assistant professor at the University of Guelph in Ontario.

Of course, this type of single-snapshot-in-time study can’t tell us whether the athletes’ training actually changed their muscle health over the years or if the athletes were somehow blessed from birth with better muscles, allowing them to become superb masters athletes.

But Dr. Power, who also led the 2010 study, said that he believes exercise does add to the numbers and improve the function of our muscle units as we grow older.

Whether we have to work out like a world-class 80-year-old athlete to benefit, however, remains in question. Most of these competitors train intensely for several hours every week, Dr. Power said. But on the plus side, some of them did not start their competitive regimens until they had reached their 50s, providing hope for the dilatory among us.

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A Diet and Exercise Plan to Lose Weight and Gain Muscle

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Credit Getty Images

If there is a holy grail of weight loss, it would be a program that allows someone to shed fat rapidly while hanging on to or even augmenting muscle. Ideally, it would also be easy.

A new study describes a workout and diet regimen that accomplishes two of those goals remarkably well. But it may not be so easy.

For most of us, losing weight and keeping it off is difficult. If you consume fewer calories than your body requires for daily operations, it turns to internal sources of fuel. Those sources consist of body fat and lean tissue, meaning muscle. When someone on a diet drops a pound of body mass (a measure that does not include water), much of that pound consists of fat. But about a third or more can be made up of muscle.

The problem with losing muscle is that, unlike fat tissue, muscle burns calories. Having less muscle means a lower resting metabolic rate, so you burn fewer calories throughout the day. Losing muscle may also discourage physical activity, which is important for maintaining weight loss.

So researchers have long been looking for weight loss programs that produce hefty amounts of fat loss but diminish any decline in muscle.

For scientists at McMaster University in Ontario, Canada, that goal seemed to demand a high dose of protein and also plenty of exercise.

As the scientists knew, amino acids in protein help muscle tissue to maintain itself and to grow. Many past studies have suggested that low-calorie but high-protein diets can result in less muscle loss than the same number of calories but less protein.

However, the best dosage of protein in these circumstances has remained unclear, as has the role, if any, for exercise.

So for the new study, which was published in The American Journal of Clinical Nutrition, the McMaster researchers rounded up 40 overweight young men who were willing to commit to an intensive weight-loss program and divided them in half.

All of the young men began a diet in which their daily calories were cut by about 40 percent (compared to what they needed to maintain weight). But for half of them, this consisted of about 15 percent protein, 35 percent fat and 50 percent carbohydrates.

The other 20 volunteers began a diet that mimicked that of the first group, except that theirs swapped the protein and fat ratios, so that 35 percent of their calories came from protein and 15 percent from fat. Over all, their protein intake was about three times the recommended dietary allowance for most people.

The researchers handled that switch by changing the make-up of a supplied drink. In the low-protein group, the beverage contained high-fat milk and no added protein. For the others, it consisted of low-fat milk and a large dollop of whey protein.

All of the men also began a grueling workout routine. Six days a week they reported to the exercise lab and completed a strenuous full-body weight training circuit, high-intensity intervals, or a series of explosive jumps and other exercises known as plyometric training.

The diet and exercise routine continued for four weeks, by the end of which time, “those guys were done,” said Stuart Phillips, who holds a research chair in skeletal muscle health at McMaster University and oversaw the study. “All they could talk about was food.”

The routine had succeeded in incinerating pounds from all of the participants. The men in both groups weighed about 11 or 12 pounds less, on average.

But it was the composition of that weight loss that differed. Unlike most people on low-calorie diets, the men on the high-protein regimen had actually gained muscle during the month, as much as three pounds of it. So in these men, almost all of the 11 or 12 pounds they had lost over all had been fat.

These results strongly suggest that extra protein is advisable during weight loss, Dr. Phillips said, to avoid stripping yourself of muscle.

But exercise is also key, Dr. Phillips continued, particularly weight training, since it is known to build muscle. Even the men on the lower-protein diet lost little muscle mass, he pointed out, which was unexpected and almost certainly due, he and his colleagues concluded, to exercise.

Of course, by the end of the month, none of the men wished to continue. This type of extreme calorie cutting combined with intense exercise “is not a sustainable program in the long term,” Dr. Phillips said. “It’s more a kind of boot camp,” he said, manageable in the short term by people who are very committed and generally very healthy.

He and his colleagues plan to conduct follow-up experiments to find a more realistic and sustainable program. They plan, too, to study female volunteers and play around with the diets’ composition, to establish definitively that it is extra protein and not reduced fat that promotes muscle gains.

In the meantime, for those hoping to become thin but not puny, various apps allow you to determine the percentage of your diet that is composed of protein. If it is below 10 or 15 percent, you might want to shift calories from fat to protein. Renew your gym membership, too.

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