PMID- 34746777
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20211110
IS  - 2624-9367 (Electronic)
IS  - 2624-9367 (Linking)
VI  - 3
DP  - 2021
TI  - Hydration Is More Important Than Exogenous Carbohydrate Intake During 
      Push-to-the-Finish Cycle Exercise in the Heat.
PG  - 742710
LID - 10.3389/fspor.2021.742710 [doi]
LID - 742710
AB  - Dehydration >/=2% loss of body mass is associated with reductions in performance 
      capacity, and carbohydrate (CHO)-electrolyte solutions (CES) are often 
      recommended to prevent dehydration and provide a source of exogenous carbohydrate 
      during exercise. It is also well established that performance capacity in the 
      heat is diminished compared to cooler conditions, a response attributable to 
      greater cardiovascular strain caused by high skin and core temperatures. Because 
      hydration status, environmental conditions, and carbohydrate availability 
      interact to influence performance capacity, we sought to determine how these 
      factors affect push-to-the-finish cycling performance. Ten young trained cyclists 
      exercised at a moderate intensity (2.5 W.kg(-1)) in a hot-dry condition [40 degrees C, 
      20% relative humidity (RH)] until dehydration of ~2% body mass. Subjects then 
      consumed either no fluid (NF) or enough fluid (water, WAT; Gatorade(R), GAT; or 
      GoodSport, GS) to replace 75% of lost body mass over 30 min. After a 30-min 
      light-intensity warm-up (1.5 W.kg(-1)) in a 35 degrees C, 20% RH environment, subjects 
      then completed a 120-kJ time trial (TT). TT time-to-completion, absolute power, 
      and relative power were significantly improved in WAT (535 +/- 214 s, 259 +/- 99 W, 
      3.3 +/- 0.9 W.kg(-1)), GAT (539 +/- 226 s, 260 +/- 110 W, 3.3 +/- 1.0 W.kg(-1)), and GS 
      (534 +/- 238 s, 262 +/- 105 W, 3.4 +/- 1.0 W.kg(-1)) compared to NF (631 +/- 310 s, 229 +/- 
      96 W, 3.0 +/- 0.9 W.kg(-1)) all (p < 0.01) with no differences between WAT, GAT, 
      and GS, suggesting that hydration is more important than carbohydrate 
      availability during exercise in the heat. A subset of four subjects returned to 
      the laboratory to repeat the WAT, GAT, and GS treatments to determine if 
      between-beverage differences in time-trial performance were evident with a longer 
      TT in thermoneutral conditions. Following dehydration, the ambient conditions in 
      the environmental chamber were reduced to 21 degrees C and 20% RH and subjects completed 
      a 250-kJ TT. All four subjects improved TT performance in the GS trial (919 +/- 353 
      s, 300 +/- 100 W, 3.61 +/- 0.86 W.kg(-1)) compared to WAT (960 +/- 376 s, 283 +/- 91 W, 
      3.43 +/- 0.83 W.kg(-1)), while three subjects improved TT performance in the GAT 
      trial (946 +/- 365 s, 293 +/- 103 W, 3.60 +/- 0.97 W.kg(-1)) compared to WAT, 
      highlighting the importance of carbohydrate availability in cooler conditions as 
      the length of a push-to-the-finish cycling task increases.
CI  - Copyright (c) 2021 Berry, Wolf, Cottle and Kenney.
FAU - Berry, Craig W
AU  - Berry CW
AD  - Noll Laboratory, Department of Kinesiology, The Pennsylvania State University, 
      University Park, PA, United States.
FAU - Wolf, S Tony
AU  - Wolf ST
AD  - Noll Laboratory, Department of Kinesiology, The Pennsylvania State University, 
      University Park, PA, United States.
FAU - Cottle, Rachel M
AU  - Cottle RM
AD  - Noll Laboratory, Department of Kinesiology, The Pennsylvania State University, 
      University Park, PA, United States.
FAU - Kenney, W Larry
AU  - Kenney WL
AD  - Noll Laboratory, Department of Kinesiology, The Pennsylvania State University, 
      University Park, PA, United States.
AD  - Graduate Program in Physiology, The Pennsylvania State University, University 
      Park, PA, United States.
LA  - eng
PT  - Journal Article
DEP - 20211021
PL  - Switzerland
TA  - Front Sports Act Living
JT  - Frontiers in sports and active living
JID - 101765780
PMC - PMC8568039
OTO - NOTNLM
OT  - carbohydrates
OT  - cycling
OT  - dairy
OT  - electrolytes
OT  - heat
OT  - hydration
OT  - sports drink
OT  - time-trial
COIS- The authors declare that the research was conducted in the absence of any 
      commercial or financial relationships that could be construed as a potential 
      conflict of interest.
EDAT- 2021/11/09 06:00
MHDA- 2021/11/09 06:01
PMCR- 2021/10/21
CRDT- 2021/11/08 06:56
PHST- 2021/07/16 00:00 [received]
PHST- 2021/09/23 00:00 [accepted]
PHST- 2021/11/08 06:56 [entrez]
PHST- 2021/11/09 06:00 [pubmed]
PHST- 2021/11/09 06:01 [medline]
PHST- 2021/10/21 00:00 [pmc-release]
AID - 10.3389/fspor.2021.742710 [doi]
PST - epublish
SO  - Front Sports Act Living. 2021 Oct 21;3:742710. doi: 10.3389/fspor.2021.742710. 
      eCollection 2021.