CONTINUOUS VS FRACTIONALIZED EXERCISE ON CALORIC EXPENDITURE IN NON-OBESE AND OBESE FEMALES.

Abstract

PURPOSE We compared the effects of fractionalized vs continuous exercise (Ex) on energy expenditure in obese (O) and non-obese (NO) young females: n=8 NO females, age=25.3 yr; ht=169.3 cm; wt=66.0 kg, BMI=23.2, VO2 peak=31.0 ml/kg/min; n=4 O females, age=30.5yr; ht=158.5 cm; wt=97.8 kg, BMI=38.8, VO2 peak=16.7 ml/kg/min METHODS Subjects were admitted to the General Clinical Research Center on 3 randomly assigned occasions: control (C), one 30 min bout of exercise (Ex) (0900-0930h, 1X30) and three 10 minute bouts of Ex (0920-0930h, 1320–1330h, 1520–1530h, 3X10) (Ex intensity = 50% of the difference between lactate threshold and peak). BMR was measured from 0600–0630h on the mornings prior to and after each condition. Identical meals were served at 1000h, 1400h, and 1800h. Caloric expenditure was monitored using open circuit spirometry from 0900–1000h, 1300–1400h, 1700–1800h (kcal Ex), and from 1030–1100h, 1430–1500h, and 1830–1900h (kcal meals). Kcal fat, kcal carbohydrate (Cho) and total kcal (Ex + meals) were calculated from VO2 and RER values. Data were analyzed by 2 way ANOVA with repeated measures. Multiple comparison adjustment was based on a p < 0.05 Least Square Difference criterion. RESULTS O and NO females expended more kcals during the 1x30 and 3x10 Ex conditions compared to C with no differences observed between Ex conditions. As expected, there was a greater increase in Tkcal expended with Ex in the NO vs. O females. NO females showed greater Cho oxidation with both Ex conditions compared to C than the O females, but there was no increase in fat oxidation in any of the conditions. There were no differences in Kcal expenditure following meals in NO or O females. CONCLUSION Both continuous and fractionalized exercise resulted in similar increases in kcal expenditure for obese and non-obese females. Contrary to previous findings in men, women utilize less fat and more carbohydrate during exercise and prior exercise did not affect post-prandial caloric expenditure.