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Effectiveness of short-term heat acclimation for highly trained athletes.
Eur J Appl Physiol. 2012 May; 112(5):1827-37.EJ

Abstract

Effectiveness of short-term acclimation has generally been undertaken using untrained and moderately-trained participants. The purpose of this study was to determine the impact of short-term (5-day) heat acclimation on highly trained athletes. Eight males (mean ± SD age 21.8 ± 2.1 years, mass 75.2 ± 4.6 kg, VO(2peak) 4.9 ± 0.2 L min(-1) and power output 400 ± 27 W) were heat acclimated under controlled hyperthermia (rectal temperature 38.5 °C), for 90-min on five consecutive days (T(a) = 39.5 °C, 60% relative humidity). Acclimation was undertaken with dehydration (no fluid-intake) during daily bouts. Participants completed a rowing-specific, heat stress test (HST) 1 day before and after acclimation (T(a) = 35 °C, 60% relative humidity). HST consisted 10-min rowing at 30% peak power output (PPO), 10 min at 60% PPO and 5-min rest before a 2-km performance test, without feedback cues. Participants received 250 mL fluid (4% carbohydrate; osmolality 240-270 mmol kg(-1)) before the HST. Body mass loss during acclimation bouts was 1.6 ± 0.3 kg (2.1%) on day 1 and 2.3 ± 0.4 kg (3.0%) on day 5. In contrast, resting plasma volume increased by 4.5 ± 4.5% from day 1 to 5 (estimated from [Hb] & Hct). Plasma aldosterone increased at rest (52.6 pg mL(-1); p = 0.03) and end-exercise (162.4 pg mL(-1); p = 0.00) from day 1 to 5 acclimation. During the HST T(re) and f(c) were lowered 0.3 °C (p = 0.00) and 14 b min(-1) (p = 0.00) after 20-min exercise. The 2-km performance time (6.52.7 min) improved by 4 s (p = 0.00). Meaningful physiological and performance improvements occurred for highly trained athletes using a short-term (5-day) heat acclimation under hyperthermia control, with dehydration.

Authors+Show Affiliations

School of Physical Education, University of Otago, Dunedin, New Zealand. andrewgarrett45@yahoo.co.ukNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

21915701

Citation

Garrett, Andrew T., et al. "Effectiveness of Short-term Heat Acclimation for Highly Trained Athletes." European Journal of Applied Physiology, vol. 112, no. 5, 2012, pp. 1827-37.
Garrett AT, Creasy R, Rehrer NJ, et al. Effectiveness of short-term heat acclimation for highly trained athletes. Eur J Appl Physiol. 2012;112(5):1827-37.
Garrett, A. T., Creasy, R., Rehrer, N. J., Patterson, M. J., & Cotter, J. D. (2012). Effectiveness of short-term heat acclimation for highly trained athletes. European Journal of Applied Physiology, 112(5), 1827-37. https://doi.org/10.1007/s00421-011-2153-3
Garrett AT, et al. Effectiveness of Short-term Heat Acclimation for Highly Trained Athletes. Eur J Appl Physiol. 2012;112(5):1827-37. PubMed PMID: 21915701.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Effectiveness of short-term heat acclimation for highly trained athletes. AU - Garrett,Andrew T, AU - Creasy,Rob, AU - Rehrer,Nancy J, AU - Patterson,Mark J, AU - Cotter,James D, Y1 - 2011/09/14/ PY - 2010/08/02/received PY - 2011/08/26/accepted PY - 2011/9/15/entrez PY - 2011/9/15/pubmed PY - 2013/5/2/medline SP - 1827 EP - 37 JF - European journal of applied physiology JO - Eur. J. Appl. Physiol. VL - 112 IS - 5 N2 - Effectiveness of short-term acclimation has generally been undertaken using untrained and moderately-trained participants. The purpose of this study was to determine the impact of short-term (5-day) heat acclimation on highly trained athletes. Eight males (mean ± SD age 21.8 ± 2.1 years, mass 75.2 ± 4.6 kg, VO(2peak) 4.9 ± 0.2 L min(-1) and power output 400 ± 27 W) were heat acclimated under controlled hyperthermia (rectal temperature 38.5 °C), for 90-min on five consecutive days (T(a) = 39.5 °C, 60% relative humidity). Acclimation was undertaken with dehydration (no fluid-intake) during daily bouts. Participants completed a rowing-specific, heat stress test (HST) 1 day before and after acclimation (T(a) = 35 °C, 60% relative humidity). HST consisted 10-min rowing at 30% peak power output (PPO), 10 min at 60% PPO and 5-min rest before a 2-km performance test, without feedback cues. Participants received 250 mL fluid (4% carbohydrate; osmolality 240-270 mmol kg(-1)) before the HST. Body mass loss during acclimation bouts was 1.6 ± 0.3 kg (2.1%) on day 1 and 2.3 ± 0.4 kg (3.0%) on day 5. In contrast, resting plasma volume increased by 4.5 ± 4.5% from day 1 to 5 (estimated from [Hb] & Hct). Plasma aldosterone increased at rest (52.6 pg mL(-1); p = 0.03) and end-exercise (162.4 pg mL(-1); p = 0.00) from day 1 to 5 acclimation. During the HST T(re) and f(c) were lowered 0.3 °C (p = 0.00) and 14 b min(-1) (p = 0.00) after 20-min exercise. The 2-km performance time (6.52.7 min) improved by 4 s (p = 0.00). Meaningful physiological and performance improvements occurred for highly trained athletes using a short-term (5-day) heat acclimation under hyperthermia control, with dehydration. SN - 1439-6327 UR - https://www.unboundmedicine.com/medline/citation/21915701/Effectiveness_of_short_term_heat_acclimation_for_highly_trained_athletes_ L2 - https://dx.doi.org/10.1007/s00421-011-2153-3 DB - PRIME DP - Unbound Medicine ER -