Exercising with less intensity but for longer periods may be best for health

THE QUESTION In today’s world, many people are spending increasing amounts of time sitting. Might short bouts of intense physical exercise help stave off ailments such as diabetes that have been linked to excessive sitting?

THIS STUDY involved 18 adults (with average age of 21) who had a basically sedentary lifestyle, were of normal weight and had normal levels of glucose (blood sugar) and lipids (cholesterol and other fats in the blood). They followed each of three regimens for four days, with at least 10 days between them. For the so-called “sitting” regimen, the participants sat for about 14 hours, walked for one hour, stood for one hour and slept (lying down) for eight hours. For the “exercise” regimen, they replaced one hour of sitting with an hour of vigorous bicycling; otherwise, the schedule for each day was the same as the sitting routine. For the third regimen, called “minimal intensity physical activity,” six of the 14 hours of sitting were replaced with four hours spent walking leisurely and two hours standing. No other exercise was permitted, and participants maintained their normal eating habits.

Activity monitors were affixed to their skin, with the results used to tabulate the energy they expended each day. The prescribed activities in each regimen were designed to have comparable daily energy expenditures.

Blood indicators of diabetes and metabolic syndrome improved somewhat when participants exercised vigorously for an hour a day, compared with when they mainly sat, but the indicators improved more when the activity was less intense (leisurely walking and standing) but longer-lasting.

WHO MAY BE AFFECTED? Sedentary adults, including those who spend many hours daily at a desk or in front of a computer screen or television. A common belief has been that health benefits of exercise increase as physical activity becomes more vigorous.

Keep it moving

CAVEATS Some of the data came from daily logs kept by the participants and from their responses on questionnaires. The study involved a small number of participants and a short period of time.

FIND THIS STUDY Feb. 13 online issue of PLoS One (dx.plos.org/10.1371/joural.pone.0055542) .

LEARN MORE ABOUT the health risks of sitting at www.mayoclinic.com. Learn how physical activity can improve your quality of life at www.heart.org (search for “physical activity”).

Linda Searing

The research described in Quick Study comes from credible, peer-reviewed journals. Nonetheless, conclusive evidence about a treatment's effectiveness is rarely found in a single study. Anyone considering changing or beginning treatment of any kind should consult with a physician.