News

How Fat Turns to Muscle Through Exercise

By Maire,

How Exercise Changes Fat and Muscle Cells

BY: Gretchen ReynoldsNY Times

Exercise promotes health, reducing most people’s risks of developing diabetes and growing obese. But just how, at a cellular level, exercise performs this beneficial magic — what physiological steps are involved and in what order — remains mysterious to a surprising degree.

Several striking new studies, however, provide some clarity by showing that exercise seems able to drastically alter how genes operate.

Genes are, of course, not static. They turn on or off, depending on what biochemical signals they receive from elsewhere in the body. When they are turned on, genes express various proteins that, in turn, prompt a range of physiological actions in the body.

One powerful means of affecting gene activity involves a process called methylation, in which methyl groups, a cluster of carbon and hydrogen atoms, attach to the outside of a gene and make it easier or harder for that gene to receive and respond to messages from the body. In this way, the behavior of the gene is changed, but not the fundamental structure of the gene itself. Remarkably, these methylation patterns can be passed on to offspring – a phenomenon known as epigenetics.

What is particularly fascinating about the methylation process is that it seems to be driven largely by how you live your life. Many recent studies have found that diet, for instance, notably affects the methylation of genes, and scientists working in this area suspect that differing genetic methylation patterns resulting from differing diets may partly determine whether someone develops diabetes and other metabolic diseases.

But the role of physical activity in gene methylation has been poorly understood, even though exercise, like diet, greatly changes the body. So several groups of scientists recently set out to determine what working out does to the exterior of our genes.

The answer, their recently published results show, is plenty.

Of the new studies, perhaps the most tantalizing, conducted principally by researchers affiliated with the Lund University Diabetes Centre in Sweden and published last month in PLoS One, began by recruiting several dozen sedentary but generally healthy adult Swedish men and sucking out some of their fat cells. Using recently developed molecular techniques, the researchers mapped the existing methylation patterns on the DNA within those cells. They also measured the men’s body composition, aerobic capacity, waist circumference, blood pressure, cholesterol levels and similar markers of health and fitness.

Then they asked the men to start working out. Under the guidance of a trainer, the volunteers began attending hourlong spinning or aerobics classes approximately twice a week for six months. By the end of that time, the men had shed fat and inches around their waists, increased their endurance and improved their blood pressure and cholesterol profiles.

Less obviously, but perhaps even more consequentially, they also had altered the methylation pattern of many of the genes in their fat cells. In fact, more than 17,900 individual locations on 7,663 separate genes in the fat cells now displayed changed methylation patterns. In most cases, the genes had become more methylated, but some had fewer methyl groups attached. Both situations affect how those genes express proteins.

The genes showing the greatest change in methylation also tended to be those that had been previously identified as playing some role in fat storage and the risk for developing diabetes or obesity.

“Our data suggest that exercise may affect the risk for Type 2 diabetes and obesity by changing DNA methylation of those genes,” says Charlotte Ling, an associate professor at Lund University and senior author of the study.

Meanwhile, other studies have found that exercise has an equally profound effect on DNA methylation within human muscle cells, even after a single workout.

To reach that conclusion, scientists from the Karolinska Institute in Stockholm and other institutions took muscle biopsies from a group of sedentary men and women and mapped their muscle cells’ methylation patterns. They then had the volunteers ride stationary bicycles until they had burned about 400 calories. Some rode strenuously, others more easily.

Afterward, a second muscle biopsy showed that DNA methylation patterns in the muscle cells were already changing after that lone workout, with some genes gaining methyl groups and some losing them. Several of the genes most altered, as in the fat cell study, are known to produce proteins that affect the body’s metabolism, including the risk for diabetes and obesity.

Interestingly, the muscle cell methylation changes were far more pronounced among the volunteers who had ridden vigorously than in those who had pedaled more gently, even though their total energy output was the same.

The overarching implication of the study’s findings, says Juleen Zierath, a professor of integrative physiology at the Karolinska Institute and senior author of the study, is that DNA methylation changes are probably “one of the earliest adaptations to exercise” and drive the bodily changes that follow.

Of course, the intricacies of that bogglingly complex process have yet to be fully teased out. Scientists do not know, for instance, whether exercise-induced methylation changes linger if someone becomes sedentary, or if resistance training has similar effects on the behavior of genes. Nor is it known whether these changes might be passed on from one generation to the next. But already it is clear, Dr. Ling says, that these new findings “are additional proof of the robust effect exercise can have on the human body, even at the level of our DNA.”

Workout Tip: Fitness Experts Weigh In On Sports Drinks and Hydration

By Maire,

Do I Need Sports Drinks?

By Jen A. Miller
Author, “Running: A Love Story”

Do you need a fitness drink when you run? Or is water good enough? To answer these questions, Anahad O’Connor, a NY Times Well reporter, spoke with a few experts on the need for hydration during exercise. Here’s what he learned:

If you’re running for less than an hour, then water is just fine. But for longer sessions – or a marathon – you should consume some kind of carbohydrate-based sports drink, says Dr. Jordan Metzl, a marathoner, endurance athlete and sports medicine doctor at the Hospital for Special Surgery in New York.

“After an hour you start depleting muscle glycogen stores to the point where it becomes difficult to keep the level of energy expenditure,” he says.

That being said, you should also be careful not to overdo it on sports drinks. A little goes a long way.

“If you just drink sports drinks, you’ll be taking in a lot of sugar and your stomach won’t be able to handle it, said Dr. Laura Goldberg, a sports medicine expert from The Cleveland Clinic.

Dr. Metzl said he prefers sports drinks with higher levels of sodium because they help to prevent muscle cramping, especially on hot and humid days. His go-to in that category is “Gatorade Endurance,” which has double the sodium (300 milligrams) and triple the potassium (140 milligrams) of original Gatorade. “I’m increasingly a fan of the double-sodium sports drinks,” Dr. Metzl said.

Be sure to stay hydrated on your runs this week. And there is some good news you should keep in mind as you head out for a run this month – training in the heat will help you perform better once it’s cooler.

Don’t forget to check out our top tips to stay cool during your Summer workout too.

Improve Your Fitness and Health in Just One Minute

By Maire,

Got a Minute? Let’s Work Out

According to a lovely new study, a single minute of intense exercise, embedded within an otherwise easy 10-minute workout, can improve fitness and health.

Just one minute.

This is good news for busy people who have tried, unsuccessfully, to fit even short workouts into their schedules. The overall time commitment for interval-training sessions is not quite as slight as many of us might wish. Consider, for instance, an interval session in which someone rides a stationary bike as hard as possible for 30 seconds, followed by four minutes or so of easy pedaling. If that person completes four of these intervals, with two or three minutes of warm-up and cool-down added at the beginning and end of the workout, the entire session lasts for almost 25 minutes, a time commitment that some people might consider unsustainable.

These concerns reached the laboratory of Martin Gibala, a professor of kinesiology at McMaster University in Ontario. He and his colleagues have conducted many of the most influential recent studies of high-intensity interval training, and many of the scientists there regularly exercise with interval training.

They, too, had noticed that interval-training sessions were not quite as truncated as some people hoped and had begun to wonder if it might be possible to lower the overall time commitment.

But if so, they wondered, how low could someone go in terms of time and still gain health and fitness benefits?

To find out, the McMaster researchers recruited a group of 14 sedentary and overweight but otherwise healthy men and women. They focused on these volunteers, because sedentary, overweight people often are on the cusp of serious health issues such as diabetes, which might be kept at bay with exercise, but sedentary people also often cite a lack of time as their reason for not exercising.

They invited the volunteers to the lab, where researchers took muscle biopsies and measured their aerobic endurance, blood pressures and blood sugar levels.

Then they asked the volunteers to complete a truly time-efficient, interval-training program using computerized stationary bicycles. Each session consisted of three 20-second “all-out” intervals, during which riders pushed the pedals absolutely as hard as they could manage, followed by two minutes of slow, easy pedaling. The riders also warmed up for two minutes and cooled down for three, for a grand total of 10 minutes of total exercise time, with one minute of that being the intense interval training.

The volunteers completed three of these sessions per week, leading to 30 minutes of weekly exercise, for six weeks.

Then they returned to the lab to be retested.

Their bodies were, it turned out, quite different now. The men and women had increased their endurance capacity by an average of 12 percent, a significant improvement. They also, as a group, had healthier blood pressures and higher levels within their muscles of certain biochemical substances that increase the number and activity of mitochondria. Mitochondria are the energy powerhouses of cells, so more mitochondria mean better endurance and fitness.

Interestingly, the male volunteers also had significantly improved their blood-sugar control, but the female volunteers had not. The researchers suspect that fundamental differences in how the genders burn sugar or fat to fuel exercise might affect how each responds to some aspects of interval training. But more research is needed with both men and women before scientists will be able to understand the import of this difference, Dr. Gibala said.

In the meantime, the message from the study that most of us will grasp at is, of course, that one minute of exercise is all you need. But Dr. Gibala would like people to remember that 10 minutes of overall exercise time is involved for a total of 30 minutes per week.

He also suspects that, with this study, scientists are plumbing the lowest limits of worthwhile exercise time. “We’ve dropped from 30-second all-out intervals to 20-second intervals,” he said, “because for many people those last 10 seconds were excruciating.” Most of us, however, can complete 20-second all-out efforts without wishing to cry, he said.

Halving the intervals again, however, to 10-second efforts, probably would mot provide the same benefits, Dr. Gibala said, although “maybe if you did more of them, it might work.” He and his colleagues are studying these and other questions related to interval training.

For now, relying on one minute of hard exercise to ease you through the holidays with your health intact seems feasible, he said. And the exercise does not need to be cycling. Sprint up stairs in 20-second bursts, he said, or even run hard in place. The point is that time constraints shouldn’t keep anyone from exercise. In the time it took to read this column, you could be done with your workout.

How to Become a Better Runner Through Walking

By Maire,

Better Running Through Walking

by Stuart Bradford – NY Times

I am more couch potato than runner. But not long ago, I decided to get myself into shape to run in the New York City Marathon, on Nov. 1, just 152 days from now. (Not that I’m counting.)

To train for my first marathon, I’m using the “run-walk” method, popularized by the distance coach Jeff Galloway, a member of the 1972 Olympic team. When I mentioned this to a colleague who runs, she snickered — a common reaction among purists.

But after interviewing several people who have used the method, I’m convinced that those of us run-walking the marathon will have the last laugh.

Contrary to what you might think, the technique doesn’t mean walking when you’re tired; it means taking brief walk breaks when you’re not.

Depending on one’s fitness level, a walk-break runner might run for a minute and walk for a minute, whether on a 5-mile training run or the 26.2-mile course on race day. A more experienced runner might incorporate a one-minute walk break for every mile of running.

Taking these breaks makes marathon training less grueling and reduces the risk of injury, Mr. Galloway says, because it gives the muscles regular recovery time during a long run. Walk breaks are a way for older, less fit and overweight people to take part in a sport that would otherwise be off limits. But most surprising are the stories from veteran runners who say run-walk training has helped them post faster race times than ever.

One of them is Tim Deegan of Jacksonville, Fla., who had run 25 marathons when his wife, Donna Deegan, a popular local newscaster and cancer survivor, began organizing a marathon to raise money for breast cancer research. When Mr. Galloway volunteered to help with the race, Ms. Deegan asked her husband to take part in run-walk training to show support.

“The only reason I did this is because I love my wife,” said Mr. Deegan, 49. “To say I was a skeptic is to put it very nicely.”

But to his surprise, he began to enjoy running more, and he found that his body recovered more quickly from long runs. His times had been slowing — to about 3 hours 45 minutes, 15 minutes shy of qualifying for the Boston Marathon — but as he ran-walked his way through the Jacksonville Marathon, “I started thinking I might have a chance to qualify for Boston again.”

He did, posting a time of 3:28.

Nadine Rihani of Nashville ran her first marathon at age 61, taking walk breaks. Her running friends urged her to adopt more traditional training, and she was eventually sidelined by back and hip pain. So she resumed run-walk training, and in April, at age 70, she finished first in her age group in the Country Music Marathon, coming in at 6:05.

“My friends who were ‘serious’ runners said, ‘You don’t need to do those walk breaks,’ ” she said. “I found out the hard way I really did.”

Dave Desposato, a 46-year-old financial analyst, began run-walk training several years ago after excessive running resulted in an overuse injury. He finished this year’s Bayshore Marathon in Traverse City, Mich., in 3:31:42, cutting 12 minutes off his previous best.

“I run enough marathons now to see everybody totally collapsing at the end is very, very common,” he said. “You wish you could share your experience with them, but they have to be willing to listen first.”

Another unconventional element of walk-break training is the frequency — typically just three days a week, with two easy runs of 20 to 60 minutes each and a long run on the weekend. The walk breaks allow runners to build up their mileage without subjecting their bodies to the stress of daily running, Mr. Galloway said.

Many runners take their own version of walk breaks without thinking about it, he says: they slow down at water stations or reduce their pace when they tire. Scheduling walk breaks earlier in a run gives the athlete control over the race and a chance to finish stronger.

While I’m planning to use run-walk training to complete my first marathon, I’ve heard from many runners who adhere to a variety of training methods. So later this week, the Well blog will have a new feature: the Run Well marathon training tool, with which you can choose any of several coaches’ training plans and then track your progress.

Besides Mr. Galloway, plans are being offered by the marathoner Greg McMillan, who is renowned for his detailed training plans that help runners reach their time goals; the New York Flyers, the city’s largest running club, which incorporates local road races into its training; and Team for Kids, a New York Road Runners Foundation charity program that trains 5,000 adult runners around the world.

The Run Well series also gives you access to top running experts, advice from elite runners, reviews of running gadgets and regular doses of inspiration to get you race-ready.

So please join me, the coaches and other running enthusiasts every day at the Well blog, nytimes.com/well, during the next five months of training. For me, this is finally the year I’ll run a marathon. I hope it will be your year too.