Ad libitum water consumption off-sets the thermal and cardiovascular strain exacerbated by dehydration during a 3-h simulated heatwave
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Ad libitum water consumption off-sets the thermal and cardiovascular strain exacerbated by dehydration during a 3-h simulated heatwave. / Graham, Connor; Morris, Nathan Bradley; Harwood, Amy E; Jay, Ollie.
I: European Journal of Applied Physiology, Bind 120, Nr. 2, 2020, s. 391-399.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Ad libitum water consumption off-sets the thermal and cardiovascular strain exacerbated by dehydration during a 3-h simulated heatwave
AU - Graham, Connor
AU - Morris, Nathan Bradley
AU - Harwood, Amy E
AU - Jay, Ollie
N1 - (Ekstern)
PY - 2020
Y1 - 2020
N2 - Purpose: To assess whether ad libitum water ingestion of different temperatures is sufficient to prevent dehydration-related exacerbations of thermal and cardiovascular strain, during exposure to conditions representative of a heatwave. Methods: Twelve participants (mean ± SD; 25 ± 4 years) exercised for 180 min at 3 METs in 40.1 ± 0.6 °C, 40.4 ± 2.1%RH four times: (i) consuming 20 °C water ad libitum (AL20); (ii) consuming 4 °C water ad libitum (AL4); (iii) replacing no fluids (NOFR); (iv) replacing sweat losses (FULLFR). Fluid consumption (FC), dehydration (%DEH), rectal temperature (Tre), rate–pressure product (RPP), forearm blood flow (FBF), mean skin temperature (Tsk), and local sweat rate (LSR) were measured/determined. Results: FC was greater in AL20 (1.30 ± 0.41 L) than AL4 (1.03 ± 0.32 L; P = 0.003). %DEH was lower (P < 0.001) in AL20 (0.11 ± 0.76%), AL4 (0.43 ± 0.64%), and FULLFR (0.01 ± 0.12%) compared to NOFR (1.93 ± 0.28%). %DEH was lower in AL20 than AL4 (P = 0.003). In NOFR, end-trial changes in Tre were greater (P < 0.001) (1.05 ± 0.27 °C) compared to all other trials, but similar among AL20 (0.72 ± 0.30 °C), AL4 (0.76 ± 0.25 °C) and FULLFR (0.74 ± 0.35 °C). End-trial RPP was higher (P < 0.001) in NOFR (12,389 ± 1578 mmHg·bpm) compared to all other trials, but similar among FULLFR (11,067 ± 1292 mmHg·bpm), AL20 (11,214 ± 2078 mmHg·bpm) and AL4 (11,089 ± 1795 mmHg·bpm). No differences in Tsk or LSR were observed among trials, but FBF was lower in NOFR compared to FULLFR (2.84 ± 0.69 vs. 3.52 ± 0.96 ml/100 ml/min; P = 0.029).Conclusion: 4 °C or 20 °C ad libitum water ingestion prevented dehydration levels that exacerbate thermal/cardiovascular strain, despite blunted fluid intake with 4 °C water. Higher core temperatures with NOFR are attributed to impaired internal heat distribution secondary to a lower FBF.
AB - Purpose: To assess whether ad libitum water ingestion of different temperatures is sufficient to prevent dehydration-related exacerbations of thermal and cardiovascular strain, during exposure to conditions representative of a heatwave. Methods: Twelve participants (mean ± SD; 25 ± 4 years) exercised for 180 min at 3 METs in 40.1 ± 0.6 °C, 40.4 ± 2.1%RH four times: (i) consuming 20 °C water ad libitum (AL20); (ii) consuming 4 °C water ad libitum (AL4); (iii) replacing no fluids (NOFR); (iv) replacing sweat losses (FULLFR). Fluid consumption (FC), dehydration (%DEH), rectal temperature (Tre), rate–pressure product (RPP), forearm blood flow (FBF), mean skin temperature (Tsk), and local sweat rate (LSR) were measured/determined. Results: FC was greater in AL20 (1.30 ± 0.41 L) than AL4 (1.03 ± 0.32 L; P = 0.003). %DEH was lower (P < 0.001) in AL20 (0.11 ± 0.76%), AL4 (0.43 ± 0.64%), and FULLFR (0.01 ± 0.12%) compared to NOFR (1.93 ± 0.28%). %DEH was lower in AL20 than AL4 (P = 0.003). In NOFR, end-trial changes in Tre were greater (P < 0.001) (1.05 ± 0.27 °C) compared to all other trials, but similar among AL20 (0.72 ± 0.30 °C), AL4 (0.76 ± 0.25 °C) and FULLFR (0.74 ± 0.35 °C). End-trial RPP was higher (P < 0.001) in NOFR (12,389 ± 1578 mmHg·bpm) compared to all other trials, but similar among FULLFR (11,067 ± 1292 mmHg·bpm), AL20 (11,214 ± 2078 mmHg·bpm) and AL4 (11,089 ± 1795 mmHg·bpm). No differences in Tsk or LSR were observed among trials, but FBF was lower in NOFR compared to FULLFR (2.84 ± 0.69 vs. 3.52 ± 0.96 ml/100 ml/min; P = 0.029).Conclusion: 4 °C or 20 °C ad libitum water ingestion prevented dehydration levels that exacerbate thermal/cardiovascular strain, despite blunted fluid intake with 4 °C water. Higher core temperatures with NOFR are attributed to impaired internal heat distribution secondary to a lower FBF.
KW - Fluid consumption
KW - Hydration
KW - Thermoregulation
KW - Thirst
UR - http://www.scopus.com/inward/record.url?scp=85076747260&partnerID=8YFLogxK
U2 - 10.1007/s00421-019-04283-7
DO - 10.1007/s00421-019-04283-7
M3 - Journal article
C2 - 31822996
AN - SCOPUS:85076747260
VL - 120
SP - 391
EP - 399
JO - European Journal of Applied Physiology
JF - European Journal of Applied Physiology
SN - 1439-6319
IS - 2
ER -
ID: 241161246