EFFECTS OF COCA CHEWING ON METABOLIC AND HORMONAL CHANGES DURING GRADED INCREMENTAL EXERCISE TO MAXIMUM

We examined the effects of 1 h of coca chewing on metabolic and hormon al responses during incremental exercise to exhaustion in traditional coca chewers (C; n = 8), and the results were compared with a group of nonchewers (n = 13). For 1 h, C chewed similar to 12 g of coca leaves that resulted in the apparition of cocaine in blood that reached 72 /- 9 ng/ml. In resting conditions, even though sympathoadrenergic acti vity (as assessed by norepinephrine and epinephrine plasma levels) was similar in both groups, C displayed a higher level of plasma free fat ty acids. Oxygen uptake measured at exhaustion and delta work efficien cy during exercise were similar in both groups. During the incremental exercise, C displayed a significantly lower arterial oxygen saturatio n that cannot be explained by a reduced ventilatory response after coc a chewing. In fact, even at maximal exercise, both ventilatory output and ventilatory equivalent were higher in C compared with nonchewers. It is concluded that the beneficial effects of coca chewing on exercis e tolerance reported frequently by traditional coca users is not relat ed to either an improved maximal exercise capacity or an increased wor k efficiency. However, during incremental exercise, coca chewing appea red to result in an increased free fatty acid availability that could be beneficial for prolonged submaximal exercise.