The relationship between level of sodium intake and exercise-associated muscle cramp among university athletes

There is limited information on the optimum amount of sodium intake for athletes to prevent muscle cramps during sports activities. Thus, this study aimed to determine the relationship between the level of sodium intake and muscle cramps among athletes. Twelve young male athletes performed uphill running (UHR; +3° incline) until their body mass was reduced by 2%. Ten minutes after UHR completion, water containing a specific level of sodium was ingested. There were two visits with two different sodium concentrations (0.3 g/L and 0.7 g/L), with a one-week washout period. Muscle cramp susceptibility was measured using threshold frequency (TF) of electrical stimulation (TENS) that induces cramps, assessed before, immediately after (0 min), and 30 and 50 minutes after ingestion. TF did not change significantly immediately after UHR for either condition (0.3 g/L: 24.8 ± 1.1 Hz; 0.7 g/L: 25.0 ± 1.2 Hz). However, 30 minutes after sodium ingestion (50 min post-UHR), TF significantly increased in both conditions: for 0.3 g/L sodium by 3.1 Hz from baseline (p < 0.05), and for 0.7 g/L by 3.9 Hz (p < 0.05). At 70 minutes after UHR, TF remained significantly higher than baseline for both sodium concentrations (0.3 g/L: 30.0 ± 1.5 Hz; 0.7 g/L: 30.9 ± 1.9 Hz, p < 0.05). In addition, no significant differences were found between the two sodium conditions at any time point. Conclusion. These findings show that both sodium levels had a similar effect in preventing exercise-associated muscle cramps (EAMCs). Further research is needed to explore the role of sodium in EAMC prevention among athletes.