The Lab: “Effects of Environmental, Local Sweat Rate (LSR), and Body Size on Core Heat Storage in Collegiate Football Players”

ABSTRACT

PURPOSE: To determine the relationship between core body temperature heat storage (HSc) and local sweat rates (LSR), heat stress, and body size in football players during 2 weeks of practices.

METHODS: Forty collegiate football players (age=20±1y, BSA=2.4±0.3m2; mean±SD) were assessed for core temperatures (Tc) using an ingestible telemetric pill and LSR with cotton gauze placed under a waterproof dermal patch on the lower back during 6 practices. HSc was estimated from change in Tc using Armstrong’s equations and LSR was calculated as the change in gauze weight adjusted for total patch surface area (0.40±0.22g/cm2 hr).

RESULTS: Maximal HSc was 134.2±100.0W/m2 (range 13.2-513.0W/m2) and maximal change in Tc was 2.3±1.0°C. The maximal change in Tc and HSc was not influenced by wet bulb globe temperature (WBGT; 26.2±3.1°C; range 20.4-29.2°C), BSA, LSR, body weight, or starting position (P>0.15 for all). Tc and HSc from start of practice to the initial measurement (mean time 39.6±31.3min) were not associated with WBGT, BSA, LSR, body weight or position (P>0.25 for all).

DISCUSSION: Under the high heat stress and with clothing that does not promote evaporative heat loss, HSc was most likely related to absolute work rate. This suggests that the focus should be on adequate rest periods in a cooler environment in order to prevent over heating. Supported by Robert and Patricia Hines Endowment for Kinesiology.

RESEARCHERS

AB Simoneaux1, NP Lemoine Jr.1, M Scott1, KS Early1, S Mullenix2, J Marucci2, TS Church3, R Castle1, NM Johannsen1.  1School of Kinesiology and 2Athletics Department, Louisiana State University, and 3Pennington Biomedical Research Center, Baton Rouge, LA

REFERENCE

Simoneaux AB, Lemoine NP Jr., Scott MC, Early KS, Mullenix S, Marucci J, Barker A, Church TS, Castle R, Johannsen NM. Effects of Environment, Local Sweat Rate (LSR), and Body Size on Core Heat Storage in Collegiate Football Players. Poster at SEACSM 2016