Although weight loss before 4 weeks was similar among the three study groups, the neurohormonal changes and BP reduction pattern were different.
It should be noted that the diminution in plasma NE was observed before weight loss or BP reduction in the three study
groups, and hence may be attributed to the effects of negative energy balance in all groups, suggesting that suppression of sympathetic activation by weight-loss programs, either caloric restriction or exercise, may have an important role in weight loss-induced BP reduction.
In our previous study in obese Caucasian subjects with the metabolic syndrome, weight loss over 12 weeks with D+EX was
associated with significantly greater decreases in total body fat mass, abdominal fat mass and waist-to-hip ratios than the D alone group, but reduction in plasma NE and NE spillover were greater in the D alone group compared with the combination group with D+EX.
The groups, including those in the EX program, had earlier and stronger improvements on HOMA-IR.52 Taken together, a calorie restricted diet, but not aerobic exercise, is a prime mover in sympathetic nervous adaptation, and aerobic exercise may have a major role in the improvement of insulin resistance. A calorie restricted diet and exercise may exert different mechanisms on weight loss, weight lossinduced BP reduction and insulin resistance.