Electrolyte beverage consumption alters electrically induced cramping threshold

Abstract

Background Recent investigations have questioned the role of hydration and electrolytes in cramp susceptibility and thus the efficacy of consuming electrolyte‐rich carbohydrate beverages (EB) to control/prevent cramping. Methods Nine euhydrated, cramp‐prone participants had their cramp susceptibility assessed by measuring the nerve stimulation threshold frequency at which cramping occurs (TF) before and after consumption of an EB (kCal: 120, Na: 840 mg, K: 320 mg, Mg: 5 mg) and placebo beverage (PB: kCal: 5, Na: 35 mg). Cramp intensity was assessed using a verbal pain scale and poststimulation electromyography (EMG). Results TF was greater in EB (14.86 ± 7.47 Hz) than PB (14.00 ± 5.03 Hz; P = .038) and reported pain was lower in EB (2.0 ± 0.6) than PB (2.7 ± 0.8; P = .025) while EMG was similar (P = .646). Discussion EB consumption decreased cramp susceptibility and pain but did not prevent cramping in any participants. These results suggest that electrolyte consumption independent of hydration can influence cramp susceptibility in young people.

Sports Dietitians Australia Position Statement: Nutrition for Exercise in Hot Environments

“…Athletes often consume Na + during exercise in the belief that it can prevent or treat some scenarios of exercise-associated muscle cramping (McCubbin et al, 2019b). Although evidence from observational studies is somewhat equivocal (Bergeron, 2003;Schwellnus, 2009), recent publications suggest that Na + intake may play a role in altering the frequency threshold in an electrically induced cramping model (Earp et al, 2019;Lau et al, 2019), which warrants further investigation. Finally, specific commentary on the practice of Na + replacement to prevent the development of hyponatremia during prolonged events (McCubbin et al, 2019b) recognizes that although hypovolemic hyponatremia (low [Na + ] plasma in concert with hypohydration) does occur in scenarios of prolonged exercise in hot conditions, the most common cause of exercise-associated hyponatremia is excessive fluid intake (Hew-Butler et al, 2015).…”

Testing electrolyte supplementation for muscle cramp

“…In a report in this issue of the Journal, cramp susceptibility was studied using the nerve stimulation cramp threshold frequency (TF) test . In this test, 2‐s trains of biphasic 80 mV electrical stimuli were applied to the tibial nerve at increasing frequencies (8–30 Hz) until cramp was induced in the flexor hallucis brevis (FHB) muscle, as reported by the subject and measured by great toe flexion load.…”

“…The authors recognize that the electrolyte‐reinforced drink also contained a large carbohydrate load and were unable to exclude this as a factor affecting their results. They discounted flavor differences and excluded failed test blinding of the study by questionnaire at the conclusion of the study …”

“…In a report in this issue of the Journal, 10 cramp susceptibility was studied using the nerve stimulation cramp threshold frequency (TF) test. 10 In this test, 2-s trains of biphasic 80 mV electrical stimuli were applied to the tibial nerve at increasing frequencies (8- induced cramp in only 9 of these 12 subjects. Urine specific gravity (< 1.020) and total and compartmental body water studies were similar before testing, and there were no significant dietary differences in electrolyte intake.…”

“…They discounted flavor differences and excluded failed test blinding of the study by questionnaire at the conclusion of the study. 10 This study 10 represents an attempt to address the value of electrolyte supplements in preventing exercise-induced cramp, as mimicked by the TF test, although it is notable that the study did not directly test the effect of exercise. Electrolyte supplements are widely held to be effective by athletes, who currently often consume "pickle juice" as a preventive remedy, a substance that contains a mix of organic substances and electrolytes, varying between manufacturers.…”