The purpose of this project was to
examine the effects of a 20-week training study, which included varied aerobic
exercise intensity and identical resistance and flexibility training, on circumference,
body mass, hormonal, health/fitness and psychophysical measures. Methods:
Thirty-two of 40 recruited overweight middle-aged women were randomized into
two training groups: low-intensity (LOW: -40% VO2peak and
high-intensity (HIGH: -80% VO2peak), for a 20-week training program.
Participants were weighed, measured, underwent VO2peak graded
exercise tests, and had blood drawn pre-training and at 10- and 20-weeks. Results:
Both groups experienced significant body mass loss at 10- and 20-weeks (LOW: p < 0.05; p < 0.01 and HIGH:
p < 0.001 and p < 0.01 respectively) and circumference loss (10-weeks—LOW: waist, hip, and thigh regions (p <
0.001); HIGH: arm (p < 0.05), waist (p < 0.05), hip (p < 0.01), thigh
(p < 0.05); 20-weeks—LOW: arm, waist, hip, thigh (p < 0.001); HIGH: arm,
hip, thigh (p < 0.001) and waist (p < 0.01)). Ghrelin levels were
elevated in the LOW group (p < 0.05) by the end of the 20-weeks of training,
whereas the HIGH group had a significant decrease (p < 0.01) at that time. Over
the training period, leptin concentrations diminished significantly in both groups
(LOW p < 0.01; HIGH p < 0.05) and were correlated to the body mass/ anthropometric
changes. Discussion: Both low- and high-intensity produced significant loss in
body mass and circumference measurements suggesting that it is not the
intensity of exercise, but rather overall energy expenditure that should be
considered. The advantage of high-intensity aerobic exercise is that it
requires less time to produce the desired energy expenditure. The changes in
ghrelin and leptin may have contributed to the energy intake during
laboratory trials.