Antioxidant Supplementation Does not Attenuate the Rise in IL-6 and C-Reactive Protein at 4300M Elevation

Abstract

0763 Exposure to high altitude (HA) and increased energy expenditure (EE) at sea level (SL) both have been shown to elevate plasma cytokines and C-reactive protein (CRP). Increased EE by military soldiers deployed to HA may cause an additive effect on the cytokine and CRP response. Antioxidants decrease the cytokine response to exercise at SL and thus may have a suppressive effect at HA. PURPOSE: To test the hypothesis that an antioxidant supplement will attenuate the cytokine (IL-6 and TNFα) and CRP response during exercise and recovery at SL and HA. METHODS: Sixteen trained males (mean ± SEM, 25 ± 1 yr, 77.7 ± 1.9 kg, 55.8 ± 1.6 ml·kg−1·min−1 VO2peak) were matched on VO2peak, ventilatory chemosensitivity, body mass, age, and body composition, and were assigned to either a placebo (PL) or antioxidant supplement (AS) group, in a double-blinded fashion. During SL testing, EE was controlled and subjects were fed a weight-stabilizing diet, but at HA subjects increased their daily EE to achieve a caloric deficit of 1500 kcal·d−1. Three weeks prior to HA, an AS (10,000 IU ß-carotene, 200 IU alpha-tocopherol acetate, 250 mg ascorbic acid, 50 μg selenium,15 mg zinc) or PL was given twice daily and continued throughout the study. At SL and HA days 1 and 13, subjects exercised at 55% of VO2peak until an EE of 1500 kcal was achieved. Blood samples were taken pre-exercise, at the end of exercise, and 2h, 4h, and 20h post exercise. RESULTS: There were no group differences between AS and PL in IL-6, CRP, or TNFα. IL-6 was significantly higher at the end of exercise, 2h, and 4h post exercise at HA day 1 compared to SL and HA day 13 (p<0.05). CRP was significantly elevated 20h post exercise at HA day 1 compared to SL and HA day 13 (p<0.05). TNFα did not differ under any condition. CONCLUSION: IL-6 and CRP are elevated following exercise during acute HA exposure and AS does not reduce this response. Supported the Department of Veterans Affairs and Department of Defense