Ubiquinone supplementation and exercise capacity in trained young and older men.

It has been suggested that ubiquinone improves exercise performance and antioxidant capacity. We studied the effects of ubiquinone supplementation (120 mg.day-1 for 6 weeks) on aerobic capacity and lipid peroxidation during exercise in 11 young (aged 22-38 years) and 8 older (aged 60-74 years), trained men. The cross-over study was double-blind and placebo-controlled. Serum ubiquinone concentration increased after supplementation (P < 0.0001 for treatment) in both age groups. The maximal oxygen uptake (VO2max) was measured using a direct incremental ergometer test. In the young subjects, the VO2max after placebo and ubiquinone treatment was 58.5 (95% confidence interval: 53.0-64.0) and 59.0 ml.min-1.kg-1 (52.2-66.8), respectively. The corresponding results in the older subjects were: 37.2 (31.7-42.7) and 33.7 ml.min-1.kg-1 (26.2-41.7) (P < 0.0001 for age group, P > 0.05 for treatment). In a prolonged test (60-min submaximal, then incremental load until exhaustion) time to exhaustion was longer after the placebo [young men: 85.7 (82.4-89.0), older men: 82.9 min (75.8-89.9)] than after ubiquinone [young men: 82.1 (78.5-85.8), older men: 77.2 min (70.1-83.7); P = 0.0003 for treatment]. Neither ubiquinone supplementation nor exercise affected serum malondialdehyde concentration. Oral ubiquinone was ineffective as an ergogenic aid in both the young and older, trained men.