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The Impact of Temperature on Critical Power Determined by a Three Minute All‐Out Test
Author(s) -
Kaiser Brendan W.,
Kruse Ka’eo K.,
Gibson Brandon M.,
Santisteban Kelsey J.,
Larson Emily A.,
Wilkins Brad W.,
Jones Andrew M.,
Halliwill John R.,
Minson Christopher T.
Publication year - 2020
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2020.34.s1.09748
Subject(s) - zoology , thermoregulation , crossover study , blood lactate , chemistry , vo2 max , core temperature , oxygen , mathematics , relative humidity , thermodynamics , medicine , physics , heart rate , biology , blood pressure , alternative medicine , pathology , placebo , organic chemistry
Critical Power (CP) separates the heavy and severe exercise domains, and work above CP (defined as W′) results in an inexorable progression to maximal oxygen uptake and rise in blood lactate concentration to fatigue. The thermoregulatory demands accompanying a rise in body core temperature (T c ) compounded with the cardiovascular challenges presented by maximal exercise in a hot environment may impact CP and W′. To date, no study has explored the effects of elevated T c and environmental temperature on CP and W′. The purpose of this study is to determine the effect of high environmental and T c on CP and W′. CP was estimated as end test power (average of the last 30 sec) from a series of three‐min “all out” tests (3MT). Volunteers (n=7, 3F) performed a 3MT during a familiarization visit and two experimental study days (thermoneutral and hot) in a randomized crossover design. Prior to the 3MT in both experimental conditions, subjects were immersed in either thermoneutral (36°C for 30 min) or hot (40.5°C) water until T c was ≥ 38.5°C. All 3MT were performed in an environmental chamber controlling for both temperature and humidity (18°C and 45% RH for thermoneutral; 38°C and 40% RH for hot). A paired t‐test was used for statistical analysis and data are presented as mean ± SE. Although variable, CP was similar between thermoneutral (245 ± 22W) and hot (243 ± 25; p=0.83), while W’ was only mildly reduced from thermoneutral (11 ± 1 kJ) to hot (9 ± 2) p=0.17. Total work performed was similar between thermoneutral (55 ± 5 kJ) and hot (53 ± 5) conditions (p=0.27) and peak power was similar between thermoneutral (827 ± 89W) and hot (809 ± 85) p=0.49. These preliminary data suggest that high T c and environmental temperature, per se , appear to have no significant impact on CP as estimated by a 3‐minute all‐out test.