cycle ergometry exercise. Testing was done at altitudes of 1525 m (5000 feet) and 4570 m (15,000 feet). Submaximal oxygen intake, oxygen debt, and blood lactate levels were significantly lower in the vitamin E-supplemented group compared with the placebo group. At the higher altitudes, the decreased availability of oxygen may increase lipid peroxidation of the red blood cell and muscle cell membranes and thereby enhance their destruction. Williams (1989) suggested that increased levels of vitamin E could counteract this effect. A recent study by Simon-Schnass and Pabst (1988) showed that lipid peroxidation was lower in a group of mountain climbers supplemented with vitamin E.
Vitamin E may play an antioxidant role in reducing muscle damage from strenuous exercise (Ebbeling and Clarkson, 1989). Exhaustive exercise that produces muscle damage also results in an increase in free radical activity (Kanter et al., 1988; Maughan et al., 1989). However, results are equivocal on whether muscle damage is reduced by vitamin E supplementation. Helgheim et al. (1979) found that vitamin E (447 IU per day) supplementation for 6 weeks did not reduce the leakage of muscle enzymes into the blood following strenuous exercise. Also, muscle soreness, a general indicator of muscle damage, was not reduced in subjects taking vitamin E supplements (600 IU per day) for 2 days before performing a strenuous exercise (Francis and Hoobler, 1986). Although Sumida et al. (1989) found that 4 weeks of vitamin E supplementation (447 IU per day) resulted in a reduced serum enzyme response to exercise, a balanced design was not used. Rather, subjects performed the same exercise before supplementation and then again after supplementation. It has been well documented that serum enzyme response is substantially reduced the second time an exercise regimen is performed (Clarkson and Tremblay, 1988; Ebbeling and Clarkson, 1989) However, Goldfarb et al. (1989) examined the effect of 800 IU of vitamin E per day for 4 weeks on lipid peroxidation in blood samples taken after a run at 80 percent . Compared to the placebo group, the vitamin E-supplemented group showed reduced levels of lipid peroxidation at rest and after running
There is currently no information concerning vitamin E supplementation for exercise in the heat. Vitamins A, C, and E are all antioxidants and may have significant roles in reducing muscle damage (via lipid peroxidation) induced by strenuous exercise. It has been suggested that work in the heat could create a hypoxic condition in the muscle due to the redistribution of blood from the muscle to the skin, although there is some question whether this occurs (Young, 1990)· While no studies have examined lipid peroxidation during exercise in the heat, it is possible that hypoxia, dehydration, or other changes induced by heat stress could exacerbate lipid peroxidation in exercising muscle. If so, the antioxidant vitamins may be useful in the reduction of heat stress. Further research in this area seems warranted.