Total amount of exercise important, not frequency, research shows

Ian Janssen and his graduate student Janine Clarke studied 2,324 adults from across Canada to determine whether the frequency of physical activity throughout the week is associated with risk factors for diabetes, heart disease and stroke.

"The findings indicate that it does not matter how adults choose to accumulate their 150 weekly minutes of physical activity," says Dr. Janssen. "For instance, someone who did not perform any physical activity on Monday to Friday but was active for 150 minutes over the weekend would obtain the same health benefits from their activity as someone who accumulated 150 minutes of activity over the week by doing 20-25 minutes of activity on a daily basis."

Physical activity was measured continuously throughout the week by having research participants wear accelerometers on their waists. Accelerometers are tiny electrical devices (about the size of a small package of matches) that record how much a person moves every minute.

Dr. Janssen divided the adults who met the physical activity guidelines (more than 150 minutes per week of aerobic activity) into those who were frequently active (active five to seven days of the week) and infrequently active (active one to four days of the week).

"The important message is that adults should aim to accumulate at least 150 minutes of weekly physical activity in whatever pattern that works for their schedule."