The influence of diet on the short-term lipid response to acute exercise

Abstract

In order to test the effect of diet on the short-term lipid response to exercise, fourteen moderately trained (VO2max: 50.2 []6.7 ml-kg-1min-1), apparently healthy men (mean age: 27.8 [] 4.3 years) consumed both a high fat (FAT) (60 []6.7 % fat, 22 []4.4 % carbohydrate, 17 []2.4 % protein) and a high carbohydrate (CHO) (I 7 ︢1.9 % fat, 63 ︢3.2 % carbohydrate, 19 []1.0 % protein ) diet for two weeks in a randomized crossover design. On the seventh day of each dietary period, V02max was measured during a treadmill run. During the last four days of the diets, plasma total cholesterol (TC), triglyceride (TG), HDL-cholesterol (HDL-C), and HDL3-cholesterol were measured the day before (PRE), and again immediately (IPE), 24 h (+24), and 48 h (+48) after one exercise bout (1000 kcal, 70% VO2max.). LDL-cholesterol and HDL2-cholesterol were calculated. Subjects abstained from all other exercise 48 h prior to and throughout this period. Concentrations were adjusted for significant plasma volume changes after exercise (p < 0.0001). A 2 (diet) X 4 (time) ANOVA with repeated measures on diet and time revealed no significant interaction between the diet and exercise treatments for any lipid variable measured. No differences were seen in any lipid variable between the two diets. However, the single session of exercise stimulated significant increases in HDL-C at both the 24 and 48 hour time points. Triglyceride showed a delayed response with a concentration 25% (p < 0.03) lower than baseline by 48 hour after exercise. Total cholesterol was 8 mg/dl lower (p < 0.001) immediately after exercise, returned to baseline levels 24 hours later, and decreased 4 mg/dl (p <0.001) by the 48 hour time point. In conclusion, a single bout of aerobic exercise was shown to stimulate short-term changes in the lipid profile. Diet was ineffective in this population as a lipid modifier.