TY - JOUR
T1 - Short-term water deprivation attenuates the exercise pressor reflex in older female adults
AU - Watso, Joseph C.
AU - Robinson, Austin T.
AU - Babcock, Matthew C.
AU - Migdal, Kamila U.
AU - Witman, Melissa A.H.
AU - Wenner, Megan M.
AU - Stocker, Sean D.
AU - Farquhar, William B.
N1 - Funding Information:
This research was supported by National Institutes of Health R01HL128388 (WBF, SDS), American Heart Association 18POST34060020 (ATR), and University of Delaware Doctoral Fellowship (JCW). This publication was made possible by the Delaware COBRE program, supported by a grant from the National Institute of General Medical Sciences – NIGMS (5 P20 GM113125) from the National Institutes of Health.
Publisher Copyright:
© 2020 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society
PY - 2020/9/1
Y1 - 2020/9/1
N2 - Older adults have reduced fluid intake and impaired body fluid and electrolyte regulation. Older female adults exhibit exaggerated exercise blood pressure (BP) responses, which is associated with an increased risk of adverse cardiovascular events. However, it is unclear if dysregulated body fluid homeostasis contributes to altered exercise BP responses in older female adults. We tested the hypothesis that short-term water deprivation (WD) increases exercise BP responses in older female adults. Fifteen female adults (eight young [25 ± 6 years] and seven older [65 ± 6 years]) completed two experimental conditions in random crossover fashion; a euhydration control condition and a stepwise reduction in water intake over three days concluding with a 16-hr WD period. During both trials, beat-to-beat BP (photoplethysmography) and heart rate (electrocardiogram) were continuously assessed during rest, handgrip exercise (30% MVC), and post-exercise ischemia (metaboreflex isolation). At screening, older compared to young female adults had greater systolic and diastolic BP (p ≤.02). Accelerometer-assessed habitual physical activity was not different between groups (p =.65). Following WD, 24-hr urine flow rate decreased, whereas thirst, urine specific gravity, and plasma osmolality increased (condition: p <.05 for all), but these WD-induced changes were not different between age groups (interaction: p ≥.31 for all). Resting systolic and diastolic BP values were higher in older compared to young adults (p <.01 for both), but were not different between experimental conditions (p ≥.20). In contrast to our hypothesis, WD was associated with attenuated systolic BP responses during handgrip exercise (post hoc: p <.01) and post-exercise ischemia (post hoc: p =.03) in older, but not young, female adults. These data suggest that reduced water intake-induced challenges to body fluid homeostasis do not contribute to exaggerated exercise BP responses in post-menopausal female adults.
AB - Older adults have reduced fluid intake and impaired body fluid and electrolyte regulation. Older female adults exhibit exaggerated exercise blood pressure (BP) responses, which is associated with an increased risk of adverse cardiovascular events. However, it is unclear if dysregulated body fluid homeostasis contributes to altered exercise BP responses in older female adults. We tested the hypothesis that short-term water deprivation (WD) increases exercise BP responses in older female adults. Fifteen female adults (eight young [25 ± 6 years] and seven older [65 ± 6 years]) completed two experimental conditions in random crossover fashion; a euhydration control condition and a stepwise reduction in water intake over three days concluding with a 16-hr WD period. During both trials, beat-to-beat BP (photoplethysmography) and heart rate (electrocardiogram) were continuously assessed during rest, handgrip exercise (30% MVC), and post-exercise ischemia (metaboreflex isolation). At screening, older compared to young female adults had greater systolic and diastolic BP (p ≤.02). Accelerometer-assessed habitual physical activity was not different between groups (p =.65). Following WD, 24-hr urine flow rate decreased, whereas thirst, urine specific gravity, and plasma osmolality increased (condition: p <.05 for all), but these WD-induced changes were not different between age groups (interaction: p ≥.31 for all). Resting systolic and diastolic BP values were higher in older compared to young adults (p <.01 for both), but were not different between experimental conditions (p ≥.20). In contrast to our hypothesis, WD was associated with attenuated systolic BP responses during handgrip exercise (post hoc: p <.01) and post-exercise ischemia (post hoc: p =.03) in older, but not young, female adults. These data suggest that reduced water intake-induced challenges to body fluid homeostasis do not contribute to exaggerated exercise BP responses in post-menopausal female adults.
KW - aging
KW - exercise pressor reflex
KW - hypohydration
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U2 - 10.14814/phy2.14581
DO - 10.14814/phy2.14581
M3 - Article
C2 - 32965797
AN - SCOPUS:85091564599
SN - 2051-817X
VL - 8
JO - Physiological Reports
JF - Physiological Reports
IS - 18
M1 - e14581
ER -