Accession Number : ADA291539

Title :   Dietary Effects on Exercising Muscle Metabolism and Performance by 31P-MRS.

Descriptive Note : Final rept. for 1993,

Corporate Author : NAVAL HEALTH RESEARCH CENTER SAN DIEGO CA

Personal Author(s) : Larson, D. E. ; Hesslink, Robert L. ; Pozos, Robert S. ; Wiley, Rudolf A. ; Hrovat, Mirko I.

PDF Url : ADA291539

Report Date : 28 JUL 1994

Pagination or Media Count : 29

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.

Descriptors :   *MILITARY PERSONNEL, *PHYSICAL FITNESS, *MUSCLES, *EXERCISE(PHYSIOLOGY), MEASUREMENT, PEAK VALUES, RATIOS, CAPACITY(QUANTITY), VENTILATION, EFFICIENCY, TIME, SHORT RANGE(TIME), LUNG, RESPIRATORY SYSTEM, MIXING, SYNCHRONISM, MUSCULOSKELETAL SYSTEM, CELLS(BIOLOGY), DIET, PH FACTOR, GAS EXCHANGE(BIOLOGY), PHOSPHORYLATION.

Subject Categories : Food, Food Service and Nutrition
      Personnel Management and Labor Relations
      Stress Physiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE