TY - JOUR
T1 - Reduced cerebrovascular and cardioventilatory responses to intermittent hypoxia in elderly
AU - Liu, Xiaoli
AU - Chen, Xiaoan
AU - Kline, Geoffrey
AU - Ross, Sarah E.
AU - Hall, James R.
AU - Ding, Yanfeng
AU - Mallet, Robert T.
AU - Shi, Xiangrong
N1 - Funding Information:
We thank our volunteer subjects for their cheerful cooperation during the study. Funding for XS was provided by an Investigator Grant from the Texas Alzheimer's Research and Care Consortium and a UNTHSC's intramural grant of Applied Research Program. RTM was supported by intramural research awards from UNTHSC's Institute for Cardiovascular and Metabolic Diseases and Office of Research Development and Commercialization. XL was supported by China Hubei Province Science Research ProjectD20191901 . XC was supported by China National Social Science Project15BTY088.
Funding Information:
We thank our volunteer subjects for their cheerful cooperation during the study. Funding for XS was provided by an Investigator Grant from the Texas Alzheimer’s Research and Care Consortium and a UNTHSC’s intramural grant of Applied Research Program. RTM was supported by intramural research awards from UNTHSC’s Institute for Cardiovascular and Metabolic Diseases and Office of Research Development and Commercialization . XL was supported by China Hubei Province Science Research Project D20191901 . XC was supported by China National Social Science Project 15BTY088 .
Publisher Copyright:
© 2019 Elsevier B.V.
PY - 2020/1
Y1 - 2020/1
N2 - Background: The impact of aging on cerebrovascular function and tissue oxygenation during graded hypoxemia is incompletely known. This study compared the age effect on these variables during cyclic hypoxemia-reoxygenation. Methods: Hypoxia-induced changes in arterial (SaO2) and cerebral tissue (ScO2) O2 saturation, middle cerebral arterial flow velocity (VMCA), estimated cerebral vascular conductance (CVC), heart rate (HR) and ventilation were compared between 12 elderly (71 ± 2 yr, 7 women) and 13 young (24 ± 3 yr, 5 women) adults during the first and fifth 5-min exposures to 10% O2. Results: Although pre-hypoxia SaO2 did not differ between the groups, ScO2 was lower (P < 0.05) in the elderly (68.4 ± 1.2%) than young (73.8 ± 0.9%) adults, commensurate with a lower resting VMCA (P < 0.05). SaO2 fell less sharply (P < 0.05) in the elderly subjects during the first and fifth hypoxia exposures. Moreover, the responses of ScO2, VMCA, CVC, HR and breathing frequency to hypoxia were attenuated in the elderly subjects. Systolic and diastolic arterial pressures fell by 2–6 mmHg during hypoxia in both young and elderly. Thus, hypoxemia developed more gradually in elderly than young adults during normobaric hypoxia, concordant with a reduced metabolic demand in the elderly. Conclusions: The elderly adults safely tolerated cyclic, moderate hypoxemia which lowered SaO2 by 20–25%, despite dampening of cerebrovascular and cardiac responses to hypoxemia.
AB - Background: The impact of aging on cerebrovascular function and tissue oxygenation during graded hypoxemia is incompletely known. This study compared the age effect on these variables during cyclic hypoxemia-reoxygenation. Methods: Hypoxia-induced changes in arterial (SaO2) and cerebral tissue (ScO2) O2 saturation, middle cerebral arterial flow velocity (VMCA), estimated cerebral vascular conductance (CVC), heart rate (HR) and ventilation were compared between 12 elderly (71 ± 2 yr, 7 women) and 13 young (24 ± 3 yr, 5 women) adults during the first and fifth 5-min exposures to 10% O2. Results: Although pre-hypoxia SaO2 did not differ between the groups, ScO2 was lower (P < 0.05) in the elderly (68.4 ± 1.2%) than young (73.8 ± 0.9%) adults, commensurate with a lower resting VMCA (P < 0.05). SaO2 fell less sharply (P < 0.05) in the elderly subjects during the first and fifth hypoxia exposures. Moreover, the responses of ScO2, VMCA, CVC, HR and breathing frequency to hypoxia were attenuated in the elderly subjects. Systolic and diastolic arterial pressures fell by 2–6 mmHg during hypoxia in both young and elderly. Thus, hypoxemia developed more gradually in elderly than young adults during normobaric hypoxia, concordant with a reduced metabolic demand in the elderly. Conclusions: The elderly adults safely tolerated cyclic, moderate hypoxemia which lowered SaO2 by 20–25%, despite dampening of cerebrovascular and cardiac responses to hypoxemia.
KW - Aging
KW - Arterial oxygen saturation
KW - Cerebral blood flow
KW - Cerebral tissue oxygenation
KW - Heart rate
KW - Hypoxemia
KW - Ventilation
UR - http://www.scopus.com/inward/record.url?scp=85072711419&partnerID=8YFLogxK
U2 - 10.1016/j.resp.2019.103306
DO - 10.1016/j.resp.2019.103306
M3 - Article
C2 - 31557538
AN - SCOPUS:85072711419
SN - 1569-9048
VL - 271
JO - Respiratory Physiology and Neurobiology
JF - Respiratory Physiology and Neurobiology
M1 - 103306
ER -