EFFECTS OF COCA CHEWING ON HORMONAL AND METABOLIC RESPONSES DURING PROLONGED SUBMAXIMAL EXERCISE

The effects of coca chewing on prolonged submaximal exercise responses were investigated in chronic coca chewers and compared with a group o f nonchewers. At rest, coca chewing during a 1-h period was followed b y a significant increase in blood glucose, free fatty acid, and norepi nephrine concentrations and a significant reduction in insulin plasma level. During prolonged (1-h) submaximal (65-70% peak O-2 uptake) exer cise, chewers displayed a significantly greater adrenergic activation (as evidenced by a higher level of plasma epinephrine) and an increase d use of fat (as evidenced by a lower respiratory exchange ratio). The gradual increase in oxygen uptake (O-2 drift) commonly observed durin g prolonged exercise was blunted in coca chewers. This blunting in O-2 drift is not related to coca-induced changes in ventilatory or lactat e responses to exercise but could possibly be related to an enhanced g lucose utilization by chewers during the late phase of exercise. The p resent results provide experimental evidence of the physiological effe cts of coca chewing that could explain the better ability of coca user s to sustain strenuous work for an extended period of time.