Journal of Applied Physiology, Vol 72, Issue 5 1754-1763, Copyright © 1992 by American Physiological Society
Effects of exercise mode and intensity on postprandial thermogenesis in lean and obese men
K. R. Segal, A. Chun, P. Coronel and V. Valdez
Department of Pediatrics, Mount Sinai School of Medicine, New York, New York 10029.
To characterize further the impact of exercise before a meal on
thermogenesis, the effects of exercise intensity and mode and the duration
of the effect of exercise on the thermic effect (TEF) of a 720-kcal mixed
meal were compared in 10 lean and 10 obese men (16 +/- 1 vs. 34 +/- 2%
fat). In study A, TEF (kcal/3 h) was significantly greater for the lean
than the obese men during rest and immediately after 1 h of cycling at 50
and 100 W. TEF was significantly greater after both exercise intensities
than during rest for the obese men, but exercise had no effect on TEF in
the lean men. In study B, TEF was significantly greater for the lean than
the obese men during rest and immediately after 1 h of leg cycling at an O2
consumption of 1.09 l/min but only marginally different after 1 h of arm
exercise at the same O2 consumption (P = 0.15). For the obese men, TEF was
greater after arm than leg cycling and greater after leg cycling than at
rest (P less than 0.01), but TEF was not different among the three
conditions for the lean men. In study C, TEF was compared at rest and
immediately and 24 h after 1 h of cycling at 100 W. TEF was greater for the
lean than the obese men under all conditions (P less than 0.05). For the
obese but not the lean men, TEF was greater both immediately after and on
the day after exercise than at rest (P less than 0.01). Thus, acute
exercise improves but does not normalize the blunted TEF in obesity; a
minimally intense bout of exercise is needed to improve TEF; exercise mode
alters thermogenesis in the obese men, even at a fixed intensity; and TEF
in the obese men is enhanced for as long as 24 h after exercise.
