Effect of alpha-lipoic acid and time-of-day on interleukin-6 response to exhaustive exercise in humans

Abstract

Circadian rhythms have an influence on human performance. Interleukin-6 is a cytokine which plays a role in muscle energy homeostasis during physical exercise. This study tested the effect of diurnal variation and alpha-lipoic acid, a natural thiol antioxidant, on skeletal muscle contractile properties, interleukin-6 response and oxidative damage. Male subjects (n=26) performed isokinetic exercise in different time-of-day. Next, the subjects were supplemented with alpha-lipoic acid for two weeks and the exercise tests were repeated. Blood samples were analyzed at baseline and immediately after exercise. Leg extensor muscle parameters were compared with time-of-day. Maximal work per single repetition and total work values were higher in the afternoon time, suggesting a time-of-day effect. Serum interleukin-6 levels increased in response to exercise, but were not associated with time-of-day. Alpha-lipoic acid did not have a significant effect on any of the measured parameters. Diurnal variations during exhaustive eccentric exercise seem to reflect muscle contractile work capacity. Exercise increases serum interleukin-6 levels irrespective of diurnal variation.

Exercise-Induced Oxidative Stress and Dietary Antoxidative

“…However its effects on isokinetic exercise performance are unknown. A recent study suggests that vitamin E and α-lipoic acid supplementation may in fact suppress skeletal muscle mitochondrial biogenesis, regardless of training status ( 70 ). Some studies have shown the benefits of lipoic acid or vitamin E supplementations in endurance trained horses ( 71 ).…”

Effects of Supplementation with Glutathione and its Precursors on Athlete Performance

“…IL-6 is a cytokine which plays a role in muscle energy homeostasis during physical exercise. Lappalainen [88] investigated the effect of LA administration on IL-6. IL-6 is an immunomodulatory cytokine produced mainly by the cells of the immune system and is considered as a marker of inflammation.…”

“…IL-6 can improve skeletal muscle energy supply and assist in the maintenance of stable blood glucose levels by stimulating lipolysis in the adipose tissue and augmenting hepatic glycogenolysis [90,91]. Lappalainen [88] has indicated that exercise increases serum IL-6 levels irrespective of diurnal variation and showed that supplementation with LA had no beneficial effect on exercise performance and exercise-induced IL-6 response. Some publications also presents a beneficial effect of supply LA in the haematological context.…”