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Tag: Physical Activity Guidelines for Americans

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Get up every hour from your seat and walk a few minutes, and cut your risk of early death by 33% (by 41% in those with chronic kidney disease). Standing won't do it - have to move. Just make sure that little walk is not to the refrigerator. Other studies have found that sitting for long periods may increase the risk for chronic disease and early death. From Scientific American:

A Little Bit of Walking Can Add up to Improve Your Health

Want to reduce your risk of dying at a young age? Try walking casually for as little as 2 minutes per hour.While it is well known that intense exercise can help you get fitter, a new study has found that even a little exercise can still go a long way. Study participants who traded time on the sofa for a total of 30 minutes of walking during the day reduced their risk of dying over a three-year period by 33 percent.

For the participants with chronic kidney disease, the risk of dying was reduced by more than 40 percent, according to the findings, published today (April 30) in the Clinical Journal of the American Society of Nephrology.

The Physical Activity Guidelines for Americans, a complement to the government's diet guidelines, recommend that people do at least 75 minutes of high-intensity aerobic physical activity (such as running, swimming or biking), or 150 minutes of moderate-intensity activity (such as brisk walking) every week to reduce the risk of obesity, diabetes and other chronic diseases. But the researchers on the new study wanted to know what the minimum threshold was—the lowest amount of physical activity that could still provide health benefits, said Dr. Srinivasan Beddhu, a kidney specialist at the University of Utah School of Medicine in Salt Lake City and lead author of the new study. [How Many Calories Am I Burning? (Infographic)]

"This study specifically looked at what intensity of activity should be used to replace sedentary activity.... being sedentary is an active choice to indulge in activities that barely raise the energy expenditure above basal metabolic rate." That threshold of intensity, Beddhu said, appears to be low. The study found that "light-intensity activities," such as casual walking, are beneficial. In contrast, activities that are "low intensity," such as standing or writing at a desk, aren't enough to provide any meaningful health benefits, the study found.

For this study, Beddhu and his colleagues at the University of Utah and the University of Colorado used information from the National Health and Nutrition Examination Survey, which includes data collected from an accelerometer, a device that measures motion. This enabled the researchers to study the activities of more than 3,600 adults representing the general U.S. population, including 383 adults with chronic kidney disease. Over the course of three years, 137 of these participants died as a result of various causes. In general, those who exercised more were less likely to die during the study period.

Positive effects of exercise could be seen down to the level of 30 minutes per day of any kind of light activity....it could be attained merely by getting up to move around a few minutes every hour. The finding could be particularly beneficial for people with kidney disease, who tend to be sedentary and inactive throughout most of the day, Beddhu added.

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Sounds like exercising in moderation has health benefits for all people, while "to excess" can be problematic. From Science Daily:

Contrary to popular belief, more exercise is not always better

There is strong epidemiological evidence of the importance of regular physical activity, such as brisk walking and jogging, in the management and rehabilitation of cardiovascular disease and in lowering the risk of death from other diseases such as hypertension, stroke, and type 2 diabetes. The Physical Activity Guidelines for Americans recommends about 150 minutes per week of moderate-intensity exercise or about 75 minutes of vigorous-intensity exercise. But there is clear evidence of an increase in cardiovascular deaths in heart attack survivors who exercise to excess.

Paul T. Williams, PhD, of the Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, and Paul D. Thompson, MD, of the Department of Cardiology, Hartford Hospital, Hartford, CT, studied the relationship between exercise and cardiovascular disease-related deaths in about 2,400 physically active heart attack survivors. This study confirmed previous reports indicating that the cardiovascular benefits for walking and running were equivalent, as long as the energy expenditures were the same (although when walking, as compared to running, it will take about twice as long to burn the same number of calories).

Remarkable dose-dependent reductions in deaths from cardiovascular events of up to 65% were seen among patients who were running less than 30 miles or walking less than 46 miles per week. Beyond this point however much of the benefit of exercise was lost, in what is described as a reverse J-curve pattern.

In the same issue, investigators in Spain report on a meta-analysis of ten cohort studies aimed at providing an accurate overview of mortality in elite athletes. The studies included over 42,000 top athletes (707 women) who had participated in a range of sports including football, baseball, track and field, and cycling, including Olympic level athletes and participants in the Tour de France.

"What we found on the evidence available was that elite athletes (mostly men) live longer than the general population, which suggests that the beneficial health effects of exercise, particularly in decreasing cardiovascular disease and cancer risk, are not necessarily confined to moderate doses," comments senior investigator Alejandro Lucia, MD, PhD, of the European University Madrid, Spain. 

"Extrapolation of the data from the current Williams and Thompson study to the general population would suggest that approximately one out of twenty people is overdoing exercise," comments James H. O'Keefe, MD, from the Mid America Heart Institute in Kansas City, MO... Along with co-authors Carl "Chip" Lavie, MD, and Barry Franklin, PhD, he explains that "we have suggested the term 'cardiac overuse injury' for this increasingly common consequence of the 'more exercise is better' strategy." 

O'Keefe, Franklin and Lavie point out that a weekly cumulative dose of vigorous exercise of not more than about five hours has been identified in several studies to be the safe upper range for long-term cardiovascular health and life expectancy, and that it may also be beneficial to take one or two days a week off from vigorous exercise, and to refrain from high-intensity exercise on an everyday basis. They propose that individuals from either end of the exercise spectrum (sedentary people and over-exercisers) would probably reap long-term health benefits by changing their physical activity levels to be in the moderate range.

"For patients with heart disease, almost all should be exercising, and generally most should be exercising 30-40 minutes most days, but from a health stand-point, there is no reason to exercise much longer than that and especially not more than 60 minutes on most days," says Lavie, who is a cardiologist at the John Ochsner Heart and Vascular Institute, New Orleans, LA.