The benefit of a supplement with the antioxidant melatonin on redox status and muscle damage in resistance-trained athletes

Abstract

Previous data showed that the administration of high doses of melatonin improved the circadian system in athletes. Here, we investigated in the same experimental paradigm whether the antioxidant properties of melatonin has also beneficial effects against exercise-induced oxidative stress and muscle damage in athletes. Twenty-four athletes were treated with 100 mg·day of melatonin or placebo 30 min before bedtime during 4 weeks in a randomized double-blind scheme. Exercise intensity was higher during the study that before starting it. Blood samples were collected before and after treatment, and plasma was used for oxygen radical absorption capacity (ORAC), lipid peroxidation (LPO), nitrite plus nitrate (NOx), and advanced oxidation protein products (AOPP) determinations. Glutathione (GSH), glutathione disulphide (GSSG) levels, and glutathione peroxidase (GPx) and reductase (GRd) activities, were measured in erythrocytes. Melatonin intake increased ORAC, reduced LPO and NOx levels, and prevented the increase of AOPP, compared to placebo group. Melatonin was also more efficient than placebo in reducing GSSG·GSH and GPx·GRd ratios. Melatonin, but not placebo, reduced creatine kinase, lactate dehydrogenase, creatinine, and total cholesterol levels. Overall, the data reflect a beneficial effect of melatonin treatment in resistance-training athletes, preventing extra- and intracellular oxidative stress induced by exercise, and yielding further skeletal muscle protection against exercise-induced oxidative damage.

Impact of Melatonin on Skeletal Muscle and Exercise

“…In any case, exogenous melatonin is useful as an antioxidant and an anti-inflammatory nutrient for prolonging muscle strength and adaptation during strenuous exercise in rodents and men in adulthood and aging [177][178][179][180]. Melatonin intake before and during exercise reduces glucose resistance and ameliorates antioxidant status in various situations, such as during preparatory training, in a soccer training camp, in resistance, or in high-trained athletes [181][182][183][184]. In particular, during strenuous training and muscular trauma induced in rodents, melatonin supplementation via different routes improved muscle recovery, inhibiting NF-kB activation and inflammatory cytokines and downregulating atrophy pathways [185].…”

Melatonin and Exercise: Their Effects on Malondialdehyde and Lipid Peroxidation

“…Low levels of ROS regulate muscle force through calcium release mechanism, and influencing myofilament structure creates adaptive response to training. However, high levels of ROS reduce force production and result in muscular fatigue [25].…”

“…Melatonin due to its scavenging ability could directly interact with a variety of oxygen-and nitrogen-based radicals. It is an antioxidant that regulates the activities of other antioxidant enzymes [6,25]. Strenuous sport activities lead to acute muscle injuries that are indicated by muscle soreness, prolong loss of muscle function, and leakage of muscle proteins.…”

“…Melatonin not only decreases the exercise-induced oxidative stress in the muscles but also enhances muscle antioxidant enzymes such as superoxide dismutase. Moreover, melatonin reduces muscle inflammatory factors such as IL-6 and TNF-alpha [25][26][27]. Melatonin could successfully manage the strenuous exerciseinduced muscle damage through several ways.…”

“…It was reported that the low-intensity aerobic training has better adaptation and lipid peroxidation prevention in sedentary individuals. Melatonin supplementation for about 2 months improves dyslipidemia, decreases LDL, and improves lipid metabolism [25].…”