Sweat Characteristics in Individuals With Varying Susceptibilities of Exercise-Associated Muscle Cramps

Michael Szymanski, Kevin C. Miller, Paul O'connor, Leslie Hildebrandt, Leah Umberger

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Szymanski, M, Miller, KC, O'Connor, P, Hildebrandt, L, and Umberger, L. Sweat characteristics in individuals with varying susceptibilities of exercise-associated muscle cramps. J Strength Cond Res 36(5): 1171-1176, 2022 - Many medical professionals believe dehydration and electrolyte losses cause exercise-associated muscle cramping (EAMC). Unlike prior field studies, we compared sweat characteristics in crampers and noncrampers but accounted for numerous factors that affect sweat characteristics including initial hydration status, diet and fluid intake, exercise conditions, and environmental conditions. Sixteen women and 14 men (mean ± SD; age = 21 ± 2 year, body mass = 69.1 ± 11.6 kg, height = 171.4 ± 9.9 cm) self-reported either no EAMC history (n = 8), low EAMC history (n = 10), or high EAMC history (n = 12). We measured Vo2max, and subjects recorded their diet. At least 3 days later, subjects ran at 70% of their Vo2max for 30 minutes in the heat (39.9 ± 0.6° C, 36 ± 2% relative humidity). Dorsal forearm sweat was collected and analyzed for sweat sodium concentration ([Na+]sw), sweat potassium concentration ([K+]sw), and sweat chloride concentration ([Cl-]sw). Sweat rate (SWR) was estimated from body mass and normalized using body surface area (BSA). Dietary fluid, Na+, and K+ingestion was estimated from a 3-day diet log. We observed no differences for any variable among the original 3 groups (p = 0.05-p = 0.73). Thus, we combined the high and low cramp groups and reanalyzed the data against the noncramping group. Again, there were no differences for [Na+]sw(p = 0.68), [K+]sw(p = 0.86), [Cl-]sw(p = 0.69), SWR/BSA (p = 0.11), dietary Na+(p = 0.14), dietary K+(p = 0.66), and fluid intake (p = 0.28). Fluid and electrolyte losses may play a more minor role in EAMC genesis than previously thought.

Original languageEnglish
Pages (from-to)1171-1176
Number of pages6
JournalJournal of Strength and Conditioning Research
Volume36
Issue number5
DOIs
StatePublished - May 1 2022

Keywords

  • chloride
  • electrolytes
  • potassium
  • sodium

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