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Effect of short‐term heat acclimation with permissive dehydration on thermoregulation and temperate exercise performance
Author(s) -
Neal R. A.,
Corbett J.,
Massey H. C.,
Tipton M. J.
Publication year - 2016
Publication title -
scandinavian journal of medicine and science in sports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.575
H-Index - 115
eISSN - 1600-0838
pISSN - 0905-7188
DOI - 10.1111/sms.12526
Subject(s) - thermoregulation , temperate climate , dehydration , cycling , zoology , acclimatization , vo2 max , intensity (physics) , medicine , exercise intensity , chemistry , biology , ecology , heart rate , biochemistry , physics , archaeology , history , quantum mechanics , blood pressure
We examined the effect of short‐term heat acclimation with permissive dehydration ( STHADe ) on heat acclimation ( HA ) and cycling performance in a temperate environment. Ten trained male cyclists [mean ( SD ) maximal oxygen uptake: 63.3(4.0) mL/kg/min; peak power output ( PPO ): 385(40) W ; training: 10 (3) h/week] underwent a STHADe program consisting of 5 days of exercise (maximum 90 min/day) in a hot environment (40 °C, 50% RH ) to elicit isothermic heat strain [rectal temperature 38.64(0.27) °C]. Participants abstained from fluids during, and 30 min after, HA sessions. Pre‐ and post‐ STHADe HA was evaluated during euhydrated fixed‐intensity exercise (60 min) in hot conditions; the effect of STHADe on thermoregulation was also examined under temperate conditions (20 min fixed‐intensity exercise; 22 °C, 60% RH ). Temperate cycling performance was assessed by a graded exercise test ( GXT ) and 20‐km time trial ( TT ). STHADe reduced thermal and cardiovascular strain in hot and temperate environments. Lactate threshold [Δ = 16 (17) W ] and GXT PPO [Δ = 6 (7) W ] were improved following STHADe ( P < 0.05), but TT performance was not affected ( P > 0.05), although there was a trend for a higher mean power ( P = 0.06). In conclusion, STHADE can reduce thermal and cardiovascular strain under hot and temperate conditions and there is some evidence of ergogenic potential for temperate exercise, but longer HA regimens may be necessary for this to meaningfully influence performance.