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Heat acclimation improves exercise performance.
J Appl Physiol (1985). 2010 Oct; 109(4):1140-7.JA

Abstract

This study examined the impact of heat acclimation on improving exercise performance in cool and hot environments. Twelve trained cyclists performed tests of maximal aerobic power (VO2max), time-trial performance, and lactate threshold, in both cool [13°C, 30% relative humidity (RH)] and hot (38°C, 30% RH) environments before and after a 10-day heat acclimation (∼50% VO2max in 40°C) program. The hot and cool condition VO2max and lactate threshold tests were both preceded by either warm (41°C) water or thermoneutral (34°C) water immersion to induce hyperthermia (0.8-1.0°C) or sustain normothermia, respectively. Eight matched control subjects completed the same exercise tests in the same environments before and after 10 days of identical exercise in a cool (13°C) environment. Heat acclimation increased VO2max by 5% in cool (66.8 ± 2.1 vs. 70.2 ± 2.3 ml·kg(-1)·min(-1), P = 0.004) and by 8% in hot (55.1 ± 2.5 vs. 59.6 ± 2.0 ml·kg(-1)·min(-1), P = 0.007) conditions. Heat acclimation improved time-trial performance by 6% in cool (879.8 ± 48.5 vs. 934.7 ± 50.9 kJ, P = 0.005) and by 8% in hot (718.7 ± 42.3 vs. 776.2 ± 50.9 kJ, P = 0.014) conditions. Heat acclimation increased power output at lactate threshold by 5% in cool (3.88 ± 0.82 vs. 4.09 ± 0.76 W/kg, P = 0.002) and by 5% in hot (3.45 ± 0.80 vs. 3.60 ± 0.79 W/kg, P < 0.001) conditions. Heat acclimation increased plasma volume (6.5 ± 1.5%) and maximal cardiac output in cool and hot conditions (9.1 ± 3.4% and 4.5 ± 4.6%, respectively). The control group had no changes in VO2max, time-trial performance, lactate threshold, or any physiological parameters. These data demonstrate that heat acclimation improves aerobic exercise performance in temperate-cool conditions and provide the scientific basis for employing heat acclimation to augment physical training programs.

Authors+Show Affiliations

Dept. of Human Physiology, Univ. of Oregon, Eugene, OR 97403-1240, USA.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Randomized Controlled Trial
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

20724560

Citation

Lorenzo, Santiago, et al. "Heat Acclimation Improves Exercise Performance." Journal of Applied Physiology (Bethesda, Md. : 1985), vol. 109, no. 4, 2010, pp. 1140-7.
Lorenzo S, Halliwill JR, Sawka MN, et al. Heat acclimation improves exercise performance. J Appl Physiol. 2010;109(4):1140-7.
Lorenzo, S., Halliwill, J. R., Sawka, M. N., & Minson, C. T. (2010). Heat acclimation improves exercise performance. Journal of Applied Physiology (Bethesda, Md. : 1985), 109(4), 1140-7. https://doi.org/10.1152/japplphysiol.00495.2010
Lorenzo S, et al. Heat Acclimation Improves Exercise Performance. J Appl Physiol. 2010;109(4):1140-7. PubMed PMID: 20724560.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Heat acclimation improves exercise performance. AU - Lorenzo,Santiago, AU - Halliwill,John R, AU - Sawka,Michael N, AU - Minson,Christopher T, Y1 - 2010/08/19/ PY - 2010/8/21/entrez PY - 2010/8/21/pubmed PY - 2011/5/24/medline SP - 1140 EP - 7 JF - Journal of applied physiology (Bethesda, Md. : 1985) JO - J. Appl. Physiol. VL - 109 IS - 4 N2 - This study examined the impact of heat acclimation on improving exercise performance in cool and hot environments. Twelve trained cyclists performed tests of maximal aerobic power (VO2max), time-trial performance, and lactate threshold, in both cool [13°C, 30% relative humidity (RH)] and hot (38°C, 30% RH) environments before and after a 10-day heat acclimation (∼50% VO2max in 40°C) program. The hot and cool condition VO2max and lactate threshold tests were both preceded by either warm (41°C) water or thermoneutral (34°C) water immersion to induce hyperthermia (0.8-1.0°C) or sustain normothermia, respectively. Eight matched control subjects completed the same exercise tests in the same environments before and after 10 days of identical exercise in a cool (13°C) environment. Heat acclimation increased VO2max by 5% in cool (66.8 ± 2.1 vs. 70.2 ± 2.3 ml·kg(-1)·min(-1), P = 0.004) and by 8% in hot (55.1 ± 2.5 vs. 59.6 ± 2.0 ml·kg(-1)·min(-1), P = 0.007) conditions. Heat acclimation improved time-trial performance by 6% in cool (879.8 ± 48.5 vs. 934.7 ± 50.9 kJ, P = 0.005) and by 8% in hot (718.7 ± 42.3 vs. 776.2 ± 50.9 kJ, P = 0.014) conditions. Heat acclimation increased power output at lactate threshold by 5% in cool (3.88 ± 0.82 vs. 4.09 ± 0.76 W/kg, P = 0.002) and by 5% in hot (3.45 ± 0.80 vs. 3.60 ± 0.79 W/kg, P < 0.001) conditions. Heat acclimation increased plasma volume (6.5 ± 1.5%) and maximal cardiac output in cool and hot conditions (9.1 ± 3.4% and 4.5 ± 4.6%, respectively). The control group had no changes in VO2max, time-trial performance, lactate threshold, or any physiological parameters. These data demonstrate that heat acclimation improves aerobic exercise performance in temperate-cool conditions and provide the scientific basis for employing heat acclimation to augment physical training programs. SN - 1522-1601 UR - https://www.unboundmedicine.com/medline/citation/20724560/Heat_acclimation_improves_exercise_performance_ L2 - http://www.physiology.org/doi/full/10.1152/japplphysiol.00495.2010?url_ver=Z39.88-2003&amp;rfr_id=ori:rid:crossref.org&amp;rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -