Paracetamol ingestion and its influence on exercise performance: a meta-analysis of randomized controlled trial

Paracetamol, a widely used analgesic, has garnered attention for its potential role in modulating exercise performance. Despite its established efficacy in pain relief, its ergogenic effects remain unclear, with conflicting evidence across various exercise modalities. The influence of paracetamol on performance markers, particularly in aerobic and anaerobic domains, is not fully understood. This meta-analysis aims to systematically assess the effects of paracetamol ingestion on exercise performance, with a specific focus on distinguishing its impact across different exercise types and intensities. A comprehensive literature search was conducted across multiple electronic databases, including PubMed, Web of Science, Cinahl, and SPORTDiscus, up to October 2022. Studies were selected based on predefmed inclusion criteria, focusing on randomized controlled trials (RCTs) assessing paracetamol's effects on aerobic and anaerobic exercise outcomes. Mean differences were pooled using fixed- or randomeffects models, depending on heterogeneity levels, and subgroup analyses were performed to evaluate the moderating effects of exercise type and intensity. A total of 18 studies involving 231 participants met the eligibility criteria and were included in the meta-analysis. The pooled data revealed a trending but non-significant enhancement in overall exercise performance following paracetamol ingestion (SMD = 0.12; 95% Cl: -0.01, 0.26; p = 0.07). Subgroup analysis suggested a more pronounced, though still non-significant, effect in aerobic endurance tasks (SMD = 0.12; 95% Cl: -0.07, 0.28; p = 0.23) compared to anaerobic activities (SMD = 0.15; 95% Cl: -0.06, 0.37; p = 0.17). Notably, paracetamol appeared more effective in moderate-intensity exercise conditions, while high-intensity tasks exhibited minimal improvements. The findings suggest that the analgesic properties of paracetamol may reduce perceived exertion and delay fatigue, particularly in endurance-based activities. However, no significant impact was observed on maximal oxygen uptake (VÓ2max). While paracetamol ingestion exhibits potential as an ergogenic aid, particularly in endurance-based exercise, the evidence remains inconclusive. The findings highlight the need for further research to clarify paracetamol's role in optimizing performance under different training conditions. Future studies should focus on the dose-response relationship, long-term effects, and potential variations across diverse athletic populations to better understand its practical application in sports performance.