Exercise-associated muscle cramp (EAMC) is painful, involuntary muscle contraction that occurs during or following exercise; dehydration and electrolytes deficits are associated factors.

A new study published in Journal of the International Society of Sports Nutrition aimed to test the hypothesis that post-exercise muscle cramp susceptibility would be increased with spring water ingestion, but reduced by oral rehydration solution (ORS) ingestion, during exercise.

This cross-over study included ten men, who performed downhill running (DHR) in hot climate (35-36 °C) for 40-60 mins, to reduce 1.5-2% of their body mass—in two conditions—spring water versus ORS. The body mass was measured at 20 mins and every 10 mins thereafter, during DHR, and 30 min post-DHR.

The findings showed that the average (±SD) baseline threshold frequency (TF) of calf muscle cramp (25.6 ± 0.7 Hz) was the same between conditions. The TF decreased 3.8 ± 2.7 to 4.5 ± 1.7 Hz from the baseline value, immediately, to 65 mins post-DHR for the spring water condition, but increased 6.5 ± 4.9 to 13.6 ± 6.0 Hz in the same time-period for the ORS condition. Whereas, hematocrit (Hct) and hemoglobin (Hb) did not change significantly for both conditions,; however, the osmolarity decreased for the spring water condition. Meanwhile, serum- sodium and chloride concentrations decreased, immediately post-DHR for the spring water condition.

Hence, ORS intake during exercise decreased muscle cramp susceptibility. In inference, it was stated that ingesting ORS appeared to be effective for preventing EAMC.

Source: 2021 Mar 15;18(1):22.doi: 10.1186/s12970-021-00414-8.