Tags

Type your tag names separated by a space and hit enter

Effects of hydration status during heat acclimation on plasma volume and performance.
Scand J Med Sci Sports. 2019 Feb; 29(2):189-199.SJ

Abstract

The impact of hydration status was investigated during a 5-day heat acclimation (HA) training protocol vs mild/cool control conditions on plasma volume (PV) and performance (20 km time-trial [TT]). Sub-elite athletes were allocated to one of two heat training groups (90 min/day): (a) dehydrated to ~2% body weight (BW) loss in heat (35°C; DEH; n = 14); (b) euhydrated heat (35°C; EUH; n = 10), where training was isothermally clamped to 38.5°C core temperature (Tc). A euhydrated mild control group (22°C; CON; n = 9) was later added, with training clamped to the same relative heart rate (~75% HRmax) as elicited during DEH and EUH; thus all groups experienced the same internal training stress (%HRmax). Five-day total thermal load was 30% greater (P < 0.001) in DEH and EUH vs CON. There were significant differences in the average percentage of maximal work rate (%Wmax) across all groups (DEH: 24 ± 6%; EUH: 34 ± 9%; CON: 48 ± 8%Wmax) during training required to elicit the same %HRmax (77 ± 4% HRmax). There were no significant differences pre-to post-HA between groups for PV (DEH: +1.7 ± 10.1%; EUH: +4.8 ± 10.2%; CON: +5.2 ± 4.0%), but there was a significant pooled group PV increase, as well as a 97% likely pooled improvement in TT performance (DEH: -1.8 ± 2.8%; EUH: -1.9 ± 2.1%, CON; -1.8 ± 2.8%; P = 0.136). Due to a lack of between-group differences for PV and TT, but pooled group increases in PV and 97% likely group increase in TT performance, over 5 days of intense training at the same average relative cardiac load suggests that overall training stress may also impact significant adaptations beyond heat and hydration stress.

Authors+Show Affiliations

Canadian Sport Institute Pacific, Victoria, British Columbia, Canada.Canadian Sport Institute Pacific, Victoria, British Columbia, Canada. School of Exercise Science, Physical and Health Education, University of Victoria, Victoria, British Columbia, Canada.Canadian Sport Institute Pacific, Victoria, British Columbia, Canada.Canadian Sport Institute Pacific, Victoria, British Columbia, Canada.School of Exercise Science, Physical and Health Education, University of Victoria, Victoria, British Columbia, Canada.Canadian Sport Institute Pacific, Victoria, British Columbia, Canada. School of Exercise Science, Physical and Health Education, University of Victoria, Victoria, British Columbia, Canada.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

30317666

Citation

Pethick, Wendy A., et al. "Effects of Hydration Status During Heat Acclimation On Plasma Volume and Performance." Scandinavian Journal of Medicine & Science in Sports, vol. 29, no. 2, 2019, pp. 189-199.
Pethick WA, Murray HJ, McFadyen P, et al. Effects of hydration status during heat acclimation on plasma volume and performance. Scand J Med Sci Sports. 2019;29(2):189-199.
Pethick, W. A., Murray, H. J., McFadyen, P., Brodie, R., Gaul, C. A., & Stellingwerff, T. (2019). Effects of hydration status during heat acclimation on plasma volume and performance. Scandinavian Journal of Medicine & Science in Sports, 29(2), 189-199. https://doi.org/10.1111/sms.13319
Pethick WA, et al. Effects of Hydration Status During Heat Acclimation On Plasma Volume and Performance. Scand J Med Sci Sports. 2019;29(2):189-199. PubMed PMID: 30317666.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Effects of hydration status during heat acclimation on plasma volume and performance. AU - Pethick,Wendy A, AU - Murray,Holly J, AU - McFadyen,Paula, AU - Brodie,Ryan, AU - Gaul,Catherine A, AU - Stellingwerff,Trent, Y1 - 2018/10/30/ PY - 2018/03/09/received PY - 2018/10/04/accepted PY - 2018/10/15/pubmed PY - 2019/4/4/medline PY - 2018/10/15/entrez KW - blood volume KW - cycling KW - dehydration KW - environment KW - hot vs mild temperatures SP - 189 EP - 199 JF - Scandinavian journal of medicine & science in sports JO - Scand J Med Sci Sports VL - 29 IS - 2 N2 - The impact of hydration status was investigated during a 5-day heat acclimation (HA) training protocol vs mild/cool control conditions on plasma volume (PV) and performance (20 km time-trial [TT]). Sub-elite athletes were allocated to one of two heat training groups (90 min/day): (a) dehydrated to ~2% body weight (BW) loss in heat (35°C; DEH; n = 14); (b) euhydrated heat (35°C; EUH; n = 10), where training was isothermally clamped to 38.5°C core temperature (Tc). A euhydrated mild control group (22°C; CON; n = 9) was later added, with training clamped to the same relative heart rate (~75% HRmax) as elicited during DEH and EUH; thus all groups experienced the same internal training stress (%HRmax). Five-day total thermal load was 30% greater (P < 0.001) in DEH and EUH vs CON. There were significant differences in the average percentage of maximal work rate (%Wmax) across all groups (DEH: 24 ± 6%; EUH: 34 ± 9%; CON: 48 ± 8%Wmax) during training required to elicit the same %HRmax (77 ± 4% HRmax). There were no significant differences pre-to post-HA between groups for PV (DEH: +1.7 ± 10.1%; EUH: +4.8 ± 10.2%; CON: +5.2 ± 4.0%), but there was a significant pooled group PV increase, as well as a 97% likely pooled improvement in TT performance (DEH: -1.8 ± 2.8%; EUH: -1.9 ± 2.1%, CON; -1.8 ± 2.8%; P = 0.136). Due to a lack of between-group differences for PV and TT, but pooled group increases in PV and 97% likely group increase in TT performance, over 5 days of intense training at the same average relative cardiac load suggests that overall training stress may also impact significant adaptations beyond heat and hydration stress. SN - 1600-0838 UR - https://www.unboundmedicine.com/medline/citation/30317666/Effects_of_hydration_status_during_heat_acclimation_on_plasma_volume_and_performance_ L2 - https://doi.org/10.1111/sms.13319 DB - PRIME DP - Unbound Medicine ER -