Dietary Effects on Exercising Muscle Metabolism and Performance by 31P-MRS.
Abstract
To determine how diet modulates short-term exercise capacity, skeletal muscle pH, and bioenergetic state were examined by 31P-magnetic resonance spectroscopy (MRS) in nine healthy volunteers. Subjects performed incremental quadriceps exercise to exhaustion following 5 day of high-CHO (HCHO) or high-fat (HFAT) diet which were randomly assigned in cross-over fashion and separated by a 2.5 day period of ad libitum mixed diet. Simultaneous measurements were made of pulmonary gas exchange, minute ventilation, and quadriceps muscle pH and phosphorylation potential. At rest and peak exercise, respiratory exchange ratio and VE were higher following HCHO vs. HFAT (p<O.O5) reflecting greater CHO utilization. VO2 peak was not increased after HCHO (p>O.O5), but exercise duration was (339 + or - 34 vs. 3O8 + or -25 sec, HCHO vs. HFAT; p<0.05). HCHO was associated with a blunted early fall Of PC/Pi vs. VO2 (-4.1 10-2 + or - 0.7 102 vs, 5.6.10-2 + or - 10-2 min/cc, HCHO vs. HFAT; p<0.05). On both study days, the slope of PC/P vs. V02, before and after the PC threshold, was correlated with exercise time. The results suggest that a diet rich CHO improves exercise efficiency through beneficial effects on intracellular phosphorylation potential.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 28, 1994
- Accession Number
- ADA291539
Entities
People
- D. E. Larson
- Mirko I. Hrovat
- Robert L. Hesslink
- Robert S. Pozos
- Rudolf A. Wiley
Organizations
- Naval Health Research Center