Does capsaicin affect physiologic and thermal responses of males during immersion in 22 degrees C?
BACKGROUND
Capsaicin alters thermoregulation in adult rats by producing a dose-dependent fall in body temperature and metabolism. The present investigation examined the thermal and metabolic responses in males who were fed capsaicin (CAP: 2 mg.kg(-1) body weight) vs. a placebo (PL: a maltodextrin capsule) prior to immersion in cold water.


METHODS
Seven Caucasian males aged 20-28 yr were immersed in 22 degrees C twice (PL vs. CAP), for 120 min. The following were examined: metabolism (M; W.m(-2)), rectal temperature (Tre; degrees C), mean skin temperature (Tsk; degrees C), tissue insulation (I; degrees C.m(-2).W(-1) and proportion of energy derived from carbohydrate (%CHO).


RESULTS
For M, Tre, I, and Tsk there was no significant differences between treatments (PL vs. CAP) when the variables were pooled jointly over time. However, significant differences across time was detected for Tre (p = 0.0003), Tsk (p = 0.0147), and M (p = 0.0036). Values for %CHO demonstrate a main effect for treatment (p = 0.0210) suggesting the CAP (46.7-/+25.9%) treatment demonstrated a decreased reliance on carbohydrate utilization for energy provision as compared to the PL (75.0+/-21.9%) treatment. Additionally, the treatment x time interaction was significant (p = 0.0096) whereby, PL differed from CAP at 5 min only.


CONCLUSIONS
From these data it appears that while M, Tre, and Tsk differed across time, a CAP (which differentially affected percent of energy derived from carbohydrate) feeding did not differentially affect the thermal and metabolic responses of males during acute cold water immersion.
Glickman-Weiss
E L
EL
Kent State University, Exercise Science Laboratory, OH 44242-0001, USA.
Hearon
C M
CM
Nelson
A G
AG
Day
R
R
D000328:Adult; D000818:Animals; D001833:Body Temperature Regulation / Q000187:drug effects* / Q000502:physiology; D002211:Capsaicin / Q000627:therapeutic use*; D003080:Cold Temperature / Q000009:adverse effects*; D004305:Dose-Response Relationship, Drug; D004734:Energy Metabolism / Q000502:physiology; D006801:Humans; D007035:Hypothermia / Q000188:drug therapy* / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology; D007101:Immersion / Q000009:adverse effects* / Q000503:physiopathology; D008297:Male; D008571:Men; D010101:Oxygen Consumption / Q000502:physiology; D051381:Rats; D013997:Time Factors
D002211:Capsaicin