Journal of Applied Physiology, Vol 77, Issue 2 828-833, Copyright © 1994 by American Physiological Society
Performance and metabolic effects of benzodiazepine during submaximal exercise
K. Collomp, M. Fortier, S. Cooper, A. Long, S. Ahmaidi, C. Prefaut, F. Wright, M. Picot and M. G. Cote
Institut National de la Recherche Scientifique Sante, Pointe Claire, Canada.
The present study examined whether benzodiazepine (BZ) intake alters
performance and selected hormonal and metabolic variables during submaximal
exercise. Seven triathletes completed two cycling trials at 85% maximum O2
uptake starting 3 h after an ingestion of either a placebo (PLA) of gelatin
or BZ (1.5 mg lorazepam) and continuing until exhaustion, according to a
double-blind randomized protocol. Blood samples were collected at rest; 5,
10, and 15 min; and exhaustion for dopamine (DA), norepinephrine (NE),
epinephrine (Epi), adrenocorticotropic hormone (ACTH), cortisol (CORT),
insulin (INS), free fatty acid, blood glucose, and lactate (La)
determinations. Time of cycling was not significantly changed after BZ or
PLA administration (22.9 +/- 2.5 vs. 23.5 +/- 3.8 min, respectively). A
decrease in CORT and an increase in INS (P < 0.05) were observed with BZ
before cycling. In comparison with rest, exercise resulted in a decrease in
INS and an increase in all the other variables investigated (P < 0.001),
but DA, NE, Epi, ACTH, CORT, La, and free fatty acid were significantly
less elevated under BZ (P < 0.05). No change was found in glucose and
INS levels between the two treatments at the end of the test. There was a
strong correlation under both PLA and BZ conditions between DA, NE, Epi,
and ACTH and also between Epi and La levels. From these data, BZ intake did
appear to alter metabolism but did not influence performance during intense
submaximal exercise.
