Effect of L-carnitine supplementation on endurance exercise in normobaric/normoxic and hypobaric/hypoxic conditions.
OBJECTIVE
To evaluate the effect of L-carnitine supplementation on improving endurance exercise in normobaric/normoxic and hypobaric/hypoxic environments.


METHODS
Six-week-endurance-trained male Sprague-Dawley rats (n = 24) were randomly divided into 2 groups: control and experimental; the latter group was supplemented with L-carnitine, administered orally in a dose of 100 mg x kg(-1) body weight. The animals were supplemented for 25 days under ambient normobaric/normoxic conditions and thereafter were exposed to 72 hours of hypobaric hypoxia equivalent to 6100 m. The supplementation was continued during the exposure. "Run to exhaustion" was recorded on day 1 (R1) (presupplementation) and on days 7 (R2), 14 (R3), 21 (R4), and 28 (R5, which followed the last 72 hours of hypoxic exposure) of supplementation. Food intake, body weight, and the biochemical measures of plasma glucose, total cholesterol, and high-density lipoprotein (HDL) cholesterol were recorded.


RESULTS
There was a significant improvement in endurance exercise, as indicated by an increase in run to exhaustion following L-carnitine supplementation under normobaric normoxia (36%-39%) and hypobaric hypoxia (50%). L-carnitine supplementation had no effect on plasma glucose levels either at sea level or after hypoxic exposure. Total cholesterol was decreased in normoxic and HDL cholesterol was increased in normoxic and hypoxic conditions, indicating a beneficial effect of exercise.


CONCLUSIONS
L-carnitine supplementation improved exercise endurance in rats exposed to normobaric normoxic and hypobaric hypoxic conditions. Such supplementation would be beneficial in delaying the onset of fatigue during prolonged exercise in both conditions, indicating its potentially beneficial use at high altitude.
Panjwani
Usha
U
Defence Institute of Physiology and Allied Sciences (DIPAS), Timarpur, Delhi, India. usha-dipas@rediffmail.com
Thakur
Lalan
L
Anand
Jag Parvesh
JP
Singh
Som Nath
SN
Amitabh
Singh
Shashi Bala
SB
Banerjee
Pratul Kumar
PK
D000284:Administration, Oral; D000818:Animals; D001274:Atmospheric Pressure; D001786:Blood Glucose; D002331:Carnitine / Q000008:administration & dosage*; D002784:Cholesterol / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D019587:Dietary Supplements; D000860:Hypoxia / Q000503:physiopathology*; D008297:Male; D010805:Physical Conditioning, Animal / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D001786:Blood Glucose; D008076:Cholesterol, HDL; D002784:Cholesterol; D002331:Carnitine