Physical activity and regular exercise have many health benefits including physical fitness, increased cardiovascular endurance, and improved muscle and bone strength. Regular exercise also contributes to a more restful night’s sleep, and has been shown to decrease stress hormones in the body. In addition, regular exercise has been shown to delay the onset of chronic medical conditions such as the metabolic syndrome till later in life. The metabolic syndrome is a condition that is characterized by a group of cardiovascular risk factors that include central obesity, high blood pressure, insulin resistance, impaired glucose tolerance, and dyslipidemia. Recently there has been some debate as to whether the duration of exercise or the intensity is the key factor in its beneficial effects. Recently, it has been found that the intensity of physical activity is more important that the duration for improved health. In other words, brisk walking confers health benefits while prolonged light walking does not.
Researchers, led by Dr. Eva Prescott of Bispebjerg University Hospital in Copenhagen, have found that brisk walking and jogging, but not light walking decreases the risk of developing metabolic syndrome. The results of their study were published online in journal BMJ Open. The researchers conducted a prospective cohort study involving 10,135 men and women aged 21 to 98 years of age enrolled in the Copenhagen City Heart Study. The study participants were evaluated for an association between leisure time physical activity, jogging, walking speed and walking volume with metabolic syndrome. The study participants were evaluated at baseline and at 10 year follow up using statistical analysis. It was found that brisk walking and jogging, but not light walking can decrease the risk of developing metabolic syndrome by up to 50%.
The authors wrote, “We found a decreased risk of developing [metabolic syndrome] with higher walking speed, jogging and high levels of [leisure time physical activity] in both men and women whereas walking volume and light physical activity were not associated with [metabolic syndrome] development. Our data indicated that the risk of developing [metabolic syndrome] may be reduced as much as 35–50% in subjects who are more physically active”.
The authors also wrote, “Our analyses did not indicate any evidence of a beneficial effect of increasing walking volume whereas walking speed and jogging both reduced [metabolic syndrome] risk after adjusting for volume of physical activity (leisure time physical activity), thus supporting the perception that intensity plays a key role in [metabolic syndrome] prevention”.
The authors concluded, “Significantly lower risk of [metabolic syndrome] was found in the moderately and highly physically active groups compared to their sedentary counterparts whereas light physical activity and even more than 1 h of walking daily did not confer protection against [metabolic syndrome]”.
The findings of this study show that the intensity of physical activity and exercise is more important than the duration, particularly with respect to walking. In fact, long durations of light walking did not confer any decreased risk of developing the metabolic syndrome upon the study participants. Thus, it is important to realize that high intensity exercise should be the goal if we are to obtain the health benefits of physical activity and exercise. The World Health Organization recommends 150 minutes of moderate intensity exercise per week for healthy adults. We should all strive to meet this recommendation in order to realize the health benefits observed in this study.
Adam Hoegsbro Laursen et al. “Intensity versus duration of physical activity: implications for the metabolic syndrome. A prospective cohort study” BMJ Open 2012; 2:e001711 doi:10.1136/bmjopen-2012-001711