Dietary vitamin E and physical exercise: I. Altered endurance capacity and plasma lipid profile in ageing rats

Abstract

The effect of vitamin E on the exercise performance and plasma lipid profile was studied in male Wistar rats of 4-(young adults), 8-(old adults), 12-(middle-age) and 22-months (old) of age. Animals were orally supplemented with vitamin E and allowed to swim for 30 min/day, 5 days/week and for a total period of 60 days. Swim velocity (S(v)), external work done (W(ext)) and endurance (E) capacity were the parameters that were used to assess the exercise performance of the trained rats that were either supplemented or non-supplemented with the dietary antioxidant. Plasma lipid profile analyses were in terms of low-density lipoprotein (LDL-C), high-density lipoprotein, (HDL-C) cholesterol and total cholesterol (C). Age-related decline in S(v) was noticeable in the 22-months old rats. However, the effect of vitamin E on the S(v) between the trained groups was not evident in any of the age groups. W(ext) increased linearly with age with no significant variations between the trainees. Trainee rats, when allowed to swim to exhaustion, showed a higher endurance capacity when supplemented with vitamin E. However, this capacity declined with age. There was a significant age-associated elevation in plasma C with corresponding increase in LDL-C. Exercise training in conjunction with vitamin E supplementation was most effective in elevating HDL-C levels in all age groups. These changes were accompanied by significant reductions in cholesterol/HDL-C ratios in animals receiving vitamin E, sedentary or otherwise. Our data suggests that it may be important to consider vitamin E while attempting to derive the benefits of swim training, both in terms of favorably altering the plasma lipid profile as well as enhancing the endurance capacity of exercise trainees. Dietary supplementation by vitamin E could attenuate the early onset of fatigue in the old.