Exercise key to health, even in short burst
People who are concerned about the amount of exercise they get can take heart. Short bursts of exercise done throughout the day can provide similar benefits to blocking out time at the gym, according to a new Duke University School of Medicine Study.
A variety of exercises, even when done in short bursts throughout the day, could help reduce Americans’ risk of disease and death, according to research appearing in the Journal of the American Heart Association.
“For about 30 years, guidelines have suggested that moderate-to-vigorous activity could provide health benefits, but only if you sustained the activity for 10 minutes or more,” said study author William E. Kraus of the Duke University School of Medicine. “That flies in the face of public health recommendations, like taking the stairs instead of the elevator, and parking farther from your destination. Those don’t take 10 minutes, so why were they recommended?”
The study is not the first to examine effects related to length of exercise, but it is the first to address " 'hard outcomes' — death or real health events, like heart attack," Kraus said.
Kraus said he recently served on the Physical Activity Guidelines Advisory Committee developing the report that will be used by the U.S. Department of Health and Human Services (DHHS) to update exercise guidelines.
Current guidelines, issued in 2008 by the U.S. Department of Health and Human Services, recommend at least 150 minutes of moderate exercise or 75 minutes of vigorous activity per week, ideally spread out over several days. Updates are due later this year.
Kraus’ study found that even brief trips up and down stairs would count toward accumulated exercise minutes as long as the intensity reaches a moderate or vigorous level of exertion. Moderate exertion was defined as brisk walking at a pace that makes it hard to carry on a conversation. Boosting that pace to a jog would be vigorous exercise for most people, he said.
The study findings are good news for most Americans, Kraus said, because they typically get their moderate or vigorous exercise in short bouts, and accumulating 30 minutes per day may be more convenient than setting a half-hour block.
For the study, Kraus and investigators from the National Cancer Institute analyzed data from 4,840 people 40 and older who participated in the National Health and Nutrition Examination Survey between 2003 and 2006. Participants wore accelerometers to quantify their physical activity and exertion. Using a national database, the researchers determined 4,140 participants were still living in 2011.
The most dramatic improvements in the overall risk for death and disease can occur with a relatively small amount of effort, and the more you do, the better the benefits, Kraus said.
In the study, people who got less than 20 minutes of moderate or vigorous activity each day had the highest risk of death. Those who got 60 minutes per day cut their risk of death by more than half — 57 percent. Getting at least 100 minutes of moderate or vigorous activity per day cut risk of death by 76 percent, the data showed.
In addition to Kraus, study authors include Pedro F. Saint-Maurice, Richard P. Troiano, and Charles E. Matthews of the National Cancer Institute.
Although this study examined subjects 40 and older, exercise is important for everyone, Kraus stated.
"My recommendation is for people to continue to do the things we have always suggested to incorporate activity throughout the day," he stated in his email. "Set a goal to move every hour. Take the stairs. Park farther from your office and get in a quick walk. I have hopes that when the [revised] Guidelines appear, these latter activities will now count toward the goal of achieving 150-300 minutes of moderate to vigorous physical activity per week."