Is melatonin as an ergogenic hormone a myth? a systematic review and meta-analysis.

PURPOSE: Melatonin supplementation has been disclosed as an ergogenic substance. However, the effectiveness of melatonin supplementation in healthy subjects has not been systematically investigated. The present study analyzed the effects of melatonin supplementation on physical performance and recovery. In addition, it was investigated whether exercise bout or training alter melatonin secretion in athletes and exercise practitioners. METHODS: This systematic review and meta-analysis were conducted and reported according to the guidelines outlined in the PRISMA statement. Based on the search and inclusion criteria, 21 studies were included in the systematic review, and 19 were included in the meta-analysis. RESULTS: Melatonin supplementation did not affect aerobic performance relative to time trial (-0.04; 95% CI: -0.51 to 0.44) and relative to VO2 (0.00; 95% CI: -0.57 to 0.57). Also, melatonin supplementation did not affect strength performance (0.19; 95% CI: -0.28 to 0.65). Only Glutathione Peroxidase (GPx) secretion increased after melatonin supplementation (1.40; 95% CI: 0.29 to 2.51). Post-exercise melatonin secretion was not changed immediately after an exercise session (0.56; 95% CI: -0.29 to 1.41) and 60 min after exercise (0.56; 95% CI: -0.29 to 1.41). CONCLUSION: The data indicate that melatonin is not an ergogenic hormone. In contrast, melatonin supplementation improves post-exercise recovery, even without altering its secretion.

Is physical performance affected by non-steroidal anti-inflammatory drugs use? A systematic review and meta-analysis.

OBJECTIVE: This systematic review and meta-analysis aim to analyze the effects of ingesting non-steroidal anti-inflammatory drugs (NSAIDs) on physical performance, muscle strength, and muscle damage in three different moments: immediately, 24 and 48 h after resistance exercise practice. METHODS: Relevant studies were researched in three databases (PubMed, Web of Science and SPORTDiscus) in April 2023. After excluding duplicates, the decision to include or exclude studies was made by two independent investigators in the following steps: (I) the study title; (II) the study abstract; and (III) the complete study manuscript. The following characteristics were recorded: (I) first author, (II) year of publication, (III) sample size, (IV) method of NSAIDs administration, (V) exercise protocol, and (VI) analyzed variable results. The studies selected were divided into trials that evaluated the effects of NSAIDs ingestion on performance indices of resistance exercise, endurance exercise and resistance training. RESULTS: The meta-analysis, based only on resistance exercises, revealed that both performance and muscle strength were similar between placebo or NSAID treatment immediately and 24 h after resistance exercise practice. An ergolytic effect was found 48 hours after resistance exercise (mean effect size (ES) = -0.42; 95% CI: -0.71, -0.12; p = 0.132), as well as reduced muscle strength (ES = -0.50; 95% CI: -0.83, -0.16; p = 0.072). Additionally, NSAID use did not prevent muscle waste as seen by the unchanged CK plasma concentration at all timetables. CONCLUSION: The data of the present meta-analysis indicate that NSAID use is ineffective in improving resistance performance and muscle strength, as well as exercise recovery. When considering the practical application of using NSAIDs to improve exercise capacity and strength gains, the present data supports that consumption of analgesic drugs as an endurance performance enhancer or as a muscle anabolic must not be recommended.