Effect of prior exercise on postprandial triglycerides in overweight young women after ingesting a high-carbohydrate meal.

To examine the effect of prior exercise on the postprandial lipid response to a high-carbohydrate meal in normal-weight (NW=BMI <25) and overweight (OW=BMI >or= 25) women (age 18-25), 10 NW and 10 OW participants completed 2 conditions separated by 1 month. In the morning, the day after control (CT=no exercise) or exercise conditions (EX=60 min cycling at 60% VO(2peak)), participants consumed a high-carbohydrate meal (80% CHO, 15% protein, 5% fat; 75 kJ/kg BM) followed by 6 hr of hourly blood sampling. Blood was analyzed for triglycerides (TG), blood glucose (BG), and insulin (IN). TG levels over the 6-hr period were lower in NW than OW (p= .021) and lower in EX than in CT (p= .006). Area under the curve (AUC) for TG was lower in NW than OW (p= .016) and EX than CT (p= .003). There were nonsignificant tendencies for reduced BG over time (p= .053) and AUC (p= .083), and IN AUC was lower in EX than in CT (p= .040) for both groups and lower in NW than in OW (p= .039). Prior exercise improved TG levels after a high-carbohydrate meal in both groups, and OW women demonstrated a greater postprandial lipemic response than NW regardless of condition. There were tendencies for improved glucose removal with prior exercise in NW vs. OW. Acute exercise can improve postprandial TG responses and might also improve postprandial BG and IN after a large meal in NW and OW young women.

Heat shock protein (HSP-72) levels in skeletal muscle following work in heat.

INTRODUCTION: Acute bouts of heat stress and exercise have been shown to independently increase heat shock protein levels; however, the combination of these two stressors on HSP-72 expression in human skeletal muscle has not been established. The purpose of this study was to determine the effect of a bout of exercise in the heat on HSP-72 expression. METHODS: There were eight recreationally active men (Age = 26.4 +/- 3.1 yr, V(O2)peak = 4.01 +/- 0.25 L min(- 1)) who completed two 30-min bouts of cycle ergometry at 75% of V(O2)peak in a hot (39 degrees C; RH 30%) and cold (9 degrees C; RH 61%) environment. Muscle biopsies were obtained from the vastus lateralis prior to, 6 h post, and 24 h post-exercise to measure HSP-72 protein. Core rectal temperature (Tc), average skin temperature (T(SK)), intramuscular temperature (T(IM)), heart rate (HR), oxygen uptake (V(O2)), sweat rate (SR), and plasma cortisol were measured to determine thermal loads. RESULTS: No significant interactions were present between V(O2) (2.80 +/- 0.2 vs. 2.65 +/- 0.1 L min(-1)) or plasma cortisol (27.1 +/- 2 vs. 19.2 +/- 4 microg dl(-1)) when comparing HT and CD. HR (184 +/- 5 vs. 159 +/- 7 bpm), T(IM) (40.7 +/- 0.2 vs. 40.0 +/- 0.2 degrees C), Tc (38.3 +/- 0.2 vs. 37.9 +/- 0.1 degrees C), T(SK) (36.7 +/- 0.2 vs. 29.6 +/- 0.8 degrees C), and SR (2.0 +/- 0.2 vs. 1.2 +/- 0.2 L h(-1)) were significantly greater when comparing HT and CD. HSP-72 was not altered as a result of either treatment (4.04 +/- 0.87 vs. 2.91 +/- 1.58 ng microg(-1) protein for HT and CD at 6 h post-exercise). DISCUSSION: Exercise in the heat produced a greater thermal load than exercise in the cold; however, no significant increases in HSP-72 were seen when comparing hot and cold conditions.