Effects of exercise training intensity on nocturnal growth hormone secretion in obese adults with the metabolic syndrome.
BACKGROUND
Abdominal adiposity is associated with reduced spontaneous GH secretion, and an increased incidence of the metabolic syndrome, type 2 diabetes, and cardiovascular disease. Exercise training increases GH secretion, induces abdominal visceral fat loss, and has been shown to improve the cardiometabolic risk factor profile. However, little is known about the effects of endurance training intensity on spontaneous GH release in obese individuals.


OBJECTIVE
Our objective was to examine the effects of 16 wk endurance training on spontaneous 12-h overnight GH secretion in adults with the metabolic syndrome.


METHODS
This randomized, controlled exercise intervention was conducted at the University of Virginia.


METHODS
A total of 34 adults with the metabolic syndrome (mean +/- sem: age: 49.1 +/- 1.8 yr) participated.


METHODS
Participants were randomized to one of three groups for 16 wk: no exercise training (control), low-intensity exercise training, or high-intensity training.


METHODS
Change in nocturnal integrated GH area under the curve (AUC) was calculated.


RESULTS
Both exercise training conditions augmented within-group nocturnal GH AUC pretrain to post-training (low-intensity exercise training approximately (upward arrow) 49%, P < 0.05; and high-intensity training approximately (upward arrow) 65%, P < 0.01), and these changes were also greater than the changes in the control group (P < 0.01). The change in nocturnal GH AUC was inversely associated with the change in fat mass across the entire sample (r = -0.34; P = 0.051; n=34) but was not significantly associated with the change in abdominal visceral fat (r = 0.02; P = 0.920; n = 34).


CONCLUSIONS
Sixteen wk of supervised exercise training in adults with the metabolic syndrome increases spontaneous nocturnal GH secretion independent of exercise training intensity.
Irving
Brian A
BA
Department of Human Services, Center for the Study of Complementary and Alternative Therapies, University of Virginia, Charlottesville, Virginia 22908, USA.
Weltman
J Y
JY
Patrie
James T
JT
Davis
Christopher K
CK
Brock
David W
DW
Swift
Damon
D
Barrett
Eugene J
EJ
Gaesser
Glenn A
GA
Weltman
Arthur
A