Exercise Benefits in Abdominally-Obese Older AdultsMonday, February 9, 2009
On my last day at the Asia-Oceanic Conference on Obesity, I listened to Steve Smith from the Pennington Biomedical Research Centre, Baton Rouge, LA, talk about the myriad benefits of exercise on skeletal muscle and other tissues (including adipose tissue itself).
Relevant in this context is a new study by Queen’s University researchers from Kingston, Ontario published last week in the Archives of Internal Medicine.
In this study, Lance Davidson and colleagues studied 136 sedentary, abdominally obese older men and women who were randomized to 6 months of resistance exercise (3 x 20 min bouts for a total of 60 min/week), aerobic exercise (5 x 30 min on a treadmill for a total of 150 min/week), aerobic and resistance exercise (3 x 30 min on a treadmill + 20 min of resistance exercise for a total of 150 min/week ), or a nonexercise control group.
Great care was taken to maintain dietary caloric intake at baseline levels in order to ensure that any caloric deficit was produced by the exercise regimen alone.
After controlling for age, sex, and baseline value, insulin resistance (as measured by euglycemic glucose clamp) improved compared with controls in the aerobic exercise and the combined exercise groups but not in the resistance exercise group. The greatest improvements were seen in the combined exercise group (~30%).
While there were significant improvements in functional limitations in in all exercise groups compared with the control group, improvements were greatest in the combined exercise group and were most pronounced in those who both lost abdominal fat and gained muscle mass.
In both the aerobic exercise and combined exercise groups total fat decreased by around 3.5 Kg and visceral fat decreased by about 1 Kg, but neither total nor visceral fat levels changed significantly in the resistance exercise or control group.
Not surprisingly, the researchers conclude that the combination of resistance and aerobic exercise is the optimal exercise strategy for simultaneous reduction in abdominal fat, insulin resistance and improving functional limitations in sedentary, abdominally obese older adults.
Thus, this study provides clear evidence for what I (and others) have long recommended to patients (not just the elderly): regular aerobic exercise combined with resistance training are an essential part of weight management.