Dpc. Van Aggel-leijssen et al., The effect of exercise training on beta-adrenergic stimulation of fat metabolism in obese men, INT J OBES, 25(1), 2001, pp. 16-23
OBJECTIVE: To investigate the in vivo effect of exercise training at high a
nd low intensity on beta -adrenergic stimulated fat metabolism in obese men
at rest.
METHOD: Twenty-three obese, healthy subjects were randomly divided in a low
-intensity exercise training program (40% VO2max, n = 7), a high-intensity
exercise training program (70% VO2max; n = 8), or a non-exercising control
group (n = 8). The exercise training program lasted for 12 weeks with a tra
ining frequency of 3 times per week. Before and after the intervention body
composition and maximal aerobic capacity were measured as well as fat meta
bolism at rest and during beta -adrenergic stimulation by isoprenaline. For
comparison, six lean subjects served as a control group. They participated
in a low-intensity exercise training program and underwent the same measur
ements as the obese subjects.
RESULTS: Relative fat oxidation decreased significantly during infusion of
an increasing dose of isoprenaline in the obese low-intensity and high-inte
nsity exercise training groups as well as in the lean group (P < 0.01). Exe
rcise training failed to influence the effect of <beta>-adrenergic stimulat
ion on relative fat oxidation in obese men at both intensities and in lean
men. In addition, beta -adrenergic-mediated lipolysis did not seem to be di
fferent after low intensity exercise training in lean and obese men. Lipoly
sis might be increased after high-intensity exercise training in obese men.
CONCLUSION: Low- and high-intensity exercise training in obese men failed t
o affect beta -adrenergic mediated relative fat oxidation in vivo. beta -Ad
renergic-mediated lipolysis might be increased in obese men after HI exerci
se training only. The effect of low-intensity exercise training on beta -ad
renergic-mediated fat metabolism was similar in lean and obese men.