The acute and long-term benefits of physical activity have long been recognized. Through improvements in glucose-insulin homeostasis, lipoprotein-lipid profile and many other metabolic pathways, physical activity promotes health and reduces the risk for the development of chronic societal cardiometabolic diseases such as type 2 diabetes and cardiovascular disease, with beneficial consequences on mortality.
Moreover, it is now well recognized that abdominal obesity, irrespective of total adiposity, is the deleterious form of overweight/obesity associated with a myriad of cardiometabolic complications. On the other hand, overweight/obesity in the absence of excess visceral adipose tissue and ectopic fat is not associated with an increased risk of developing metabolic disorders. To what extent physical activity modulates the relationship of abdominal obesity to related morbidity and mortality remains a highly relevant question.
A recent meta-analysis produced by a group of international experts has examined the respective contributions of physical activity and waist circumference, as a marker of abdominal obesity, to mortality risk. To achieve this goal, the authors have gathered data from several cohorts where level of physical activity was measured by accelerometry. A total of 19,216 participants (with 1,443 deaths observed over the follow-up) were classified according to a low or a high waist circumference and further subgrouped into three categories of moderate-to-vigorous physical activity (MVPA). When compared to individuals with an elevated waist circumference and low MVPA, a reduced mortality rate was observed among participants with medium and high MVPA, irrespective of waist circumference. However, there was no reduction of mortality risk in individuals with a low waist circumference and low MVPA. Similar results were observed when analyses were restricted to never smokers.
These results reiterate the importance of adopting a physically active lifestyle to reduce mortality risk. Even a low waist circumference is not associated with optimally low mortality risk if people are not physically active. Having a normal body weight or waist circumference is not enough: physical activity is a must for all!