The effect of magnesium supplementation on exercise-related muscle cramp, recovery,performance and sleep in athletes: A systematic review

Background: Athletes often turn to supplements due to beliefs of performance advantages, with magnesium being a popular choice. Research suggests potential ergogenic effects of magnesium on exercise performance and recovery, although conclusive evidence is lacking in athletic populations. Aim: To assess the effects of magnesium supplementation on athletic performance, recovery, muscle cramps and sleep in athletes.Methods: MEDLINE, EMBASE, SPORTDiscus and CINAHL were searched in October 2023. Inclusion criteria were athletes, oral magnesium supplementation and athletic performance outcomes. Data were extracted from eligible studies including study design, length of intervention, number of participants, age, gender, level of athleticism and comparator, as well as specific athletic performance, recovery and biomarker outcome measures.Results: While some studies reported no significant differences for endurance, others found positive effects like faster swim time and lower systolic blood pressure. Acute supplementation increased bench press 1RM, but chronic supplementation had no effect. Recovery outcomes varied, with some studies showing reduced muscle soreness with supplementation. Indirect biochemical outcomes like creatine kinase and blood glucose levels also displayed mixed responses to supplementation. Conclusion: While magnesium is widely promoted to athletes, current research supporting use is limited. This review indicated minimal impact on athletic performance, recovery, and muscle cramps, with no evidence on sleep. Optimal dosage and form of magnesium remains uncertain, aligning with the Australian Institute of Sport's categorisation as a Category-C supplement. Future studies should standardise methodology to address confounding factors that may have influenced previous findings.