There were, remarkably, almost no differences in fitness gains among the groups. The women working out twice a week had become as powerful and aerobically fit as those who had worked out six times a week. There were no discernible differences in cytokine levels among the groups, either.
However, the women exercising four times per week were now expending far more energy, over all, than the women in either of the other two groups. They were burning about 225 additional calories each day, beyond what they expended while exercising, compared to their calorie burning at the start of the experiment.
The twice-a-week exercisers also were using more energy each day than they had been at first, burning almost 100 calories more daily, in addition to the calories used during workouts.
But the women who had been assigned to exercise six times per week were now expending considerably less daily energy than they had been at the experiment’s start, the equivalent of almost 200 fewer calories each day, even though they were exercising so assiduously.
“We think that the women in the twice-a-week and four-times-a-week groups felt more energized and physically capable” after several months of training than they had at the start of the study, says Gary Hunter, a U.A.B. professor who led the experiment. Based on conversations with the women, he says he thinks they began opting for stairs over escalators and walking for pleasure.
The women working out six times a week, though, reacted very differently. “They complained to us that working out six times a week took too much time,” Dr. Hunter says. They did not report feeling fatigued or physically droopy. Their bodies were not producing excessive levels of cytokines, sending invisible messages to the body to slow down.
Rather, they felt pressed for time and reacted, it seems, by making choices like driving instead of walking and impatiently avoiding the stairs.
Why Four Workouts a Week May Be Better Than Six
By GRETCHEN REYNOLDS
New York Times
February 13, 2013
A common concern about exercise is that if you don’t do it almost every day, you won’t achieve much health benefit. But a commendable new study suggests otherwise, showing that a fairly leisurely approach to scheduling workouts may actually be more beneficial than working out almost daily.
For the new study, published this month in Medicine & Science in Sports & Exercise, researchers at the University of Alabama at Birmingham gathered 72 older, sedentary women, ages 60 to 74, and randomly assigned them to one of three exercise groups.
One group began lifting weights once a week and performing an endurance-style workout, like jogging or bike riding, on another day.
Another group lifted weights twice a week and jogged or rode an exercise bike twice a week.
The final group, as you may have guessed, completed three weight-lifting and three endurance sessions, or six weekly workouts.
The exercise, which was supervised by researchers, was easy at first and meant to elicit changes in both muscles and endurance. Over the course of four months, the intensity and duration gradually increased, until the women were jogging moderately for 40 minutes and lifting weights for about the same amount of time.
The researchers were hoping to find out which number of weekly workouts would be, Goldilocks-like, just right for increasing the women’s fitness and overall weekly energy expenditure.
Some previous studies had suggested that working out only once or twice a week produced few gains in fitness, while exercising vigorously almost every day sometimes led people to become less physically active, over all, than those formally exercising less. Researchers theorized that the more grueling workout schedule caused the central nervous system to respond as if people were overdoing things, sending out physiological signals that, in an unconscious internal reaction, prompted them to feel tired or lethargic and stop moving so much.
To determine if either of these possibilities held true among their volunteers, the researchers in the current study tracked the women’s blood levels of cytokines, a substance related to stress that is thought to be one of the signals the nervous system uses to determine if someone is overdoing things physically. They also measured the women’s changing aerobic capacities, muscle strength, body fat, moods and, using sophisticated calorimetry techniques, energy expenditure over the course of each week.
By the end of the four-month experiment, all of the women had gained endurance and strength and shed body fat, although weight loss was not the point of the study. The scientists had not asked the women to change their eating habits.
There were, remarkably, almost no differences in fitness gains among the groups. The women working out twice a week had become as powerful and aerobically fit as those who had worked out six times a week. There were no discernible differences in cytokine levels among the groups, either.
However, the women exercising four times per week were now expending far more energy, over all, than the women in either of the other two groups. They were burning about 225 additional calories each day, beyond what they expended while exercising, compared to their calorie burning at the start of the experiment.
The twice-a-week exercisers also were using more energy each day than they had been at first, burning almost 100 calories more daily, in addition to the calories used during workouts.
But the women who had been assigned to exercise six times per week were now expending considerably less daily energy than they had been at the experiment’s start, the equivalent of almost 200 fewer calories each day, even though they were exercising so assiduously.
“We think that the women in the twice-a-week and four-times-a-week groups felt more energized and physically capable” after several months of training than they had at the start of the study, says Gary Hunter, a U.A.B. professor who led the experiment. Based on conversations with the women, he says he thinks they began opting for stairs over escalators and walking for pleasure.
The women working out six times a week, though, reacted very differently. “They complained to us that working out six times a week took too much time,” Dr. Hunter says. They did not report feeling fatigued or physically droopy. Their bodies were not producing excessive levels of cytokines, sending invisible messages to the body to slow down.
Rather, they felt pressed for time and reacted, it seems, by making choices like driving instead of walking and impatiently avoiding the stairs.
Despite the cautionary note, those who insist on working out six times per week need not feel discouraged. As long as you consciously monitor your activity level, the findings suggest, you won’t necessarily and unconsciously wind up moving less over all.
But the more fundamental finding of this study, Dr. Hunter says, is that “less may be more,” a message that most likely resonates with far more of us. The women exercising four times a week “had the greatest overall increase in energy expenditure,” he says. But those working out only twice a week “weren’t far behind.”
Showing posts with label exercise. Show all posts
Showing posts with label exercise. Show all posts
Wednesday, December 18, 2013
Monday, May 27, 2013
Exercise Alters DNA within minutes
How Exercise Can Change Your DNA
By Alice Park
Time
March 07, 2012
Just 20 Minutes of Exercise Can Change Your Genes MyHealthNewsDaily
Exercise does a lot of good things — it burns calories, helps keep your weight in check and lowers your risk of heart disease, stroke and diabetes. Now add one more thing to the list: physical activity can change your DNA.
Unlike the aberrations and genetic mutations caused by carcinogens and toxins, exercise-induced alterations to DNA are more like tune-ups, helping muscles to work better and more efficiently. What’s more, these changes occur even after a single 20-minute workout.
Juleen Zierath, a professor of physiology at the Karolinska Institute in Stockholm, reports with her colleagues in the journal Cell Metabolism about these very early changes that muscle cells undergo the first time you get off the couch and into the gym. The researchers worked with a group of 14 young men and women who were relatively sedentary, and asked them to work out on an exercise bike that measured their maximum activity levels. The participants also volunteered to give up a little bit of muscle, from their quadriceps, in a relatively painless biopsy procedure performed under local anesthesia. The researchers took the biopsy of muscle cells once before the participants exercised, and again within 20 minutes afterward.
VIDEO: Walking While Working: Healthland’s Belinda Luscombe Tries the Treadmill Desk
Using the biopsied samples, researchers compared the activity in a series of muscle-related genes before and after exercise. More genes were turned on in the cells taken after the exercise and the participants’ DNA showed less methylation, a molecular process in which chemicals called methyl groups settle on the DNA and limit the cell’s ability to access, or switch on, certain genes. By controlling how much methylation goes on in certain cells at specific times, the body regulates which genes in the DNA are activated — that’s what differentiates the development of an an eye cell, for example, from that of a liver cell.
Methylation also helps to prime muscle cells for a bout of exercise, getting them to pump out the right enzymes and nutrients the muscle needs to get energy and burn calories while you’re pounding the pavement during that mile-long jog. “We are trying to get at the early messages that the muscle is [receiving in order] to say, ‘Something is happening here, we need to coordinate so we can get more enzymes and more machinery on board so we can cope with the demands of this exercise,’” says Zierath.
The more intense the exercise, she says, the more the methyl groups are on the move. She and her team were able to see this firsthand by comparing gene activity in participants who also agreed to exercise at two different intensities over a period of a week. On one visit, they were asked to cycle until they reached 40% of their maximum capacity; on another occasion, they biked until they reached 80% of their maximum. The muscle biopsies following the 80% sessions showed a lower concentration of methyl groups — and therefore more RNA, which is the first byproduct of gene activity — than samples taken after the 40% sessions.
MORE: Why Exercise Won’t Make You Thin
To confirm the role of exercise on gene expression in muscle, the scientists then studied how calcium affected the entire system. When muscle cells start to gear up for intense activity like exercise, they release calcium, which fuels the contraction process. When the scientists blocked calcium production, the effect disappeared, and the muscles didn’t contract as much.
That’s when Zierath threw in some coffee — or more specifically, caffeine. Caffeine triggers the release of calcium, and can enhance the way methyl groups move aside to turn on the genes that help muscles contract. When she added caffeine to a lab dish containing cells from the leg muscles of rats, the muscle cells showed lower concentrations of methyl groups and more mRNA — a similar effect as seen after exercise — as she expected.
But, says Zierath, that doesn’t mean you can skip the workout for a cup of coffee instead. “Most of the physiological effect of the caffeine we drink is on the central nervous system, and not dispersed to all the muscles,” she says. “In order to get the same kind of effect we saw in the cells, you would have to drink 50 cups of coffee a day, which is close to the lethal dose. In my mind, half an hour of moderately high intensity exercise is sufficient to do the same thing.”
Read more: http://healthland.time.com/2012/03/07/how-exercise-can-change-your-dna/#ixzz2UXQNygP3
Sunday, March 3, 2013
We may live longer with moderate exercise than with vigorous exercise
June 6, 2012
Moderation as the Sweet Spot for Exercise
By GRETCHEN REYNOLDS
New York Times
Moderate exercise may be more beneficial than vigorous workouts.Thor Swift for The New York Times Moderate exercise may be more beneficial than vigorous workouts.
For people who exercise but fret that they really should be working out more, new studies may be soothing. The amount of exercise needed to improve health and longevity, this new science shows, is modest, and more is not necessarily better.
That is the message of the newest and perhaps most compelling of the studies, which was presented on Saturday at the annual meeting of the American College of Sports Medicine in San Francisco. For it, researchers at the University of South Carolina Arnold School of Public Health and other institutions combed through the health records of 52,656 American adults who’d undergone physicals between 1971 and 2002 as part of the Aerobics Center Longitudinal Study at the Cooper Institute in Dallas. Each participant completed physical testing and activity questionnaires and returned for at least one follow-up visit.
The researchers found that about 27 percent of the participants reported regularly running, although in wildly varying amounts and paces.
The scientists then checked death reports.
Over the course of the study, 2,984 of the participants died. But the incidence was much lower among the group that ran. Those participants had, on average, a 19 percent lower risk of dying from any cause than non-runners.
Notably, in closely parsing the participants’ self-reported activities, the researchers found that running in moderation provided the most benefits. Those who ran 1 to 20 miles per week at an average pace of about 10 or 11 minutes per mile — in other words, jogging — reduced their risk of dying during the study more effectively than those who didn’t run, those (admittedly few) who ran more than 20 miles a week, and those who typically ran at a pace swifter than seven miles an hour.
“These data certainly support the idea that more running is not needed to produce extra health and mortality benefits,” said Dr. Carl J. Lavie, medical director of cardiac rehabilitation and prevention at the Ochsner Medical Center in New Orleans and an author of the study. “If anything,” he continued, “it appears that less running is associated with the best protection from mortality risk. More is not better, and actually, more could be worse.”
His analysis echoes the results of another new examination of activity and mortality, in which Danish scientists used 27 years’ worth of data collected for the continuing Copenhagen City Heart Study. They reported that those Danes who spent one to two and a half hours per week jogging at a “slow or average pace” during the study period had longer life spans than their more sedentary peers and than those who ran at a faster pace.
This decidedly modest amount of exercise led to an increase of, on average, 6.2 years in the life span of male joggers and 5.6 years in women.
“We can say with certainty that regular jogging increases longevity,” Dr. Peter Schnorr, a cardiologist and an author of the study, said in presenting the findings at a clinical meeting organized last month by the European Association for Cardiovascular Prevention and Rehabilitation. “The good news is that you don’t actually need to do that much to reap the benefits.”
“The relationship appears much like alcohol intakes,” he continued. “Mortality is lower in people reporting moderate jogging than in non-joggers or those undertaking extreme levels of exercise.”
There’s further confirmation of that idea in the findings of a large study of exercise habits published last year in The Lancet, which showed that among a group of 416,175 Taiwanese adults, 92 minutes a week of moderate exercise, like walking, gentle jogging or cycling, increased life span by about three years and decreased the risk of mortality from any cause by about 14 percent.
In that study, those who embarked on more ambitious exercise programs did gain additional risk reduction, as seems only fair, but the benefits plateaued rapidly. For each further 15 minutes per day of moderate exercise that someone completed beyond the first 92, his or her mortality risk fell, but by only about another 4 percent.
Whether and at what point more exercise becomes counterproductive remains uncertain. “In general, it appears that exercise, like any therapy, results in a bell-shaped curve in terms of response and benefit,” says Dr. James H. O’Keefe, a cardiologist and lead author of a thought-provoking review article published on Monday in Mayo Clinic Proceedings that examines whether extreme amounts of vigorous exercise, particularly running, can harm the heart.
“To date, the data suggests that walking and light jogging are almost uniformly beneficial for health and do increase life span,” Dr. O’Keefe says. “But with more vigorous or prolonged exercise, the benefits can become questionable.
“I’m a fan of distance running,” he adds. “I run. But after about 45 to 60 minutes a day, you reach a point of diminishing returns, and at some point, you risk toxicity.”
His advice? The study by Dr. Lavie and his colleagues offers excellent guidelines for safe and effective exercise, Dr. O’Keefe says. “Twenty miles a week or less of jogging at a 10- or 11-minute-mile pace can add years to your life span. That’s very good news.” Indeed it is — especially since that routine happens to replicate almost exactly my own weekly exercise regimen.
“I wouldn’t automatically discourage people from doing more if they really want to” and are not experiencing side effects, like extreme fatigue or repeated injuries, Dr. O’Keefe continued. “But the message from the latest data is that the sweet spot for exercise seems to come with less.”
Gretchen Reynolds is the author of “The First 20 Minutes: Surprising Science Reveals How We Can Exercise Better, Train Smarter, Live Longer” (Hudson Street Press, 2012).
We hope you’ll “Like” the new Well on Facebook, where you’ll find news and conversations about fitness, food and family health.
Moderation as the Sweet Spot for Exercise
By GRETCHEN REYNOLDS
New York Times
Moderate exercise may be more beneficial than vigorous workouts.Thor Swift for The New York Times Moderate exercise may be more beneficial than vigorous workouts.
For people who exercise but fret that they really should be working out more, new studies may be soothing. The amount of exercise needed to improve health and longevity, this new science shows, is modest, and more is not necessarily better.
That is the message of the newest and perhaps most compelling of the studies, which was presented on Saturday at the annual meeting of the American College of Sports Medicine in San Francisco. For it, researchers at the University of South Carolina Arnold School of Public Health and other institutions combed through the health records of 52,656 American adults who’d undergone physicals between 1971 and 2002 as part of the Aerobics Center Longitudinal Study at the Cooper Institute in Dallas. Each participant completed physical testing and activity questionnaires and returned for at least one follow-up visit.
The researchers found that about 27 percent of the participants reported regularly running, although in wildly varying amounts and paces.
The scientists then checked death reports.
Over the course of the study, 2,984 of the participants died. But the incidence was much lower among the group that ran. Those participants had, on average, a 19 percent lower risk of dying from any cause than non-runners.
Notably, in closely parsing the participants’ self-reported activities, the researchers found that running in moderation provided the most benefits. Those who ran 1 to 20 miles per week at an average pace of about 10 or 11 minutes per mile — in other words, jogging — reduced their risk of dying during the study more effectively than those who didn’t run, those (admittedly few) who ran more than 20 miles a week, and those who typically ran at a pace swifter than seven miles an hour.
“These data certainly support the idea that more running is not needed to produce extra health and mortality benefits,” said Dr. Carl J. Lavie, medical director of cardiac rehabilitation and prevention at the Ochsner Medical Center in New Orleans and an author of the study. “If anything,” he continued, “it appears that less running is associated with the best protection from mortality risk. More is not better, and actually, more could be worse.”
His analysis echoes the results of another new examination of activity and mortality, in which Danish scientists used 27 years’ worth of data collected for the continuing Copenhagen City Heart Study. They reported that those Danes who spent one to two and a half hours per week jogging at a “slow or average pace” during the study period had longer life spans than their more sedentary peers and than those who ran at a faster pace.
This decidedly modest amount of exercise led to an increase of, on average, 6.2 years in the life span of male joggers and 5.6 years in women.
“We can say with certainty that regular jogging increases longevity,” Dr. Peter Schnorr, a cardiologist and an author of the study, said in presenting the findings at a clinical meeting organized last month by the European Association for Cardiovascular Prevention and Rehabilitation. “The good news is that you don’t actually need to do that much to reap the benefits.”
“The relationship appears much like alcohol intakes,” he continued. “Mortality is lower in people reporting moderate jogging than in non-joggers or those undertaking extreme levels of exercise.”
There’s further confirmation of that idea in the findings of a large study of exercise habits published last year in The Lancet, which showed that among a group of 416,175 Taiwanese adults, 92 minutes a week of moderate exercise, like walking, gentle jogging or cycling, increased life span by about three years and decreased the risk of mortality from any cause by about 14 percent.
In that study, those who embarked on more ambitious exercise programs did gain additional risk reduction, as seems only fair, but the benefits plateaued rapidly. For each further 15 minutes per day of moderate exercise that someone completed beyond the first 92, his or her mortality risk fell, but by only about another 4 percent.
Whether and at what point more exercise becomes counterproductive remains uncertain. “In general, it appears that exercise, like any therapy, results in a bell-shaped curve in terms of response and benefit,” says Dr. James H. O’Keefe, a cardiologist and lead author of a thought-provoking review article published on Monday in Mayo Clinic Proceedings that examines whether extreme amounts of vigorous exercise, particularly running, can harm the heart.
“To date, the data suggests that walking and light jogging are almost uniformly beneficial for health and do increase life span,” Dr. O’Keefe says. “But with more vigorous or prolonged exercise, the benefits can become questionable.
“I’m a fan of distance running,” he adds. “I run. But after about 45 to 60 minutes a day, you reach a point of diminishing returns, and at some point, you risk toxicity.”
His advice? The study by Dr. Lavie and his colleagues offers excellent guidelines for safe and effective exercise, Dr. O’Keefe says. “Twenty miles a week or less of jogging at a 10- or 11-minute-mile pace can add years to your life span. That’s very good news.” Indeed it is — especially since that routine happens to replicate almost exactly my own weekly exercise regimen.
“I wouldn’t automatically discourage people from doing more if they really want to” and are not experiencing side effects, like extreme fatigue or repeated injuries, Dr. O’Keefe continued. “But the message from the latest data is that the sweet spot for exercise seems to come with less.”
Gretchen Reynolds is the author of “The First 20 Minutes: Surprising Science Reveals How We Can Exercise Better, Train Smarter, Live Longer” (Hudson Street Press, 2012).
We hope you’ll “Like” the new Well on Facebook, where you’ll find news and conversations about fitness, food and family health.
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