Effects of aging on the cerebrovascular orthostatic response

Kim, Yu-Sok; Bogert, Lysander W. J.; Immink, Rogier V.; Harms, Mark P M; Colier, Willy N.J.M.; Lieshout, Johannes J. van

doi:10.1016/j.neurobiolaging.2009.02.019

Cited by 26 publications

(28 citation statements)

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“…Indeed, fixing a line through several singular subject MAP/CBF relationships ignores the potential of chronic resetting, e.g., in the case with sustained hypertension [7]. Upon closer examination of the response for CBF (or a related index of CBF) to a change in MAP, recent studies have revealed that this relationship appears to be more pressure passive [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] than previously described. However, the limitations to drawing inferences from the majority of recent studies are threefold.…”

Section: Introductionmentioning

confidence: 99%

“…However, the limitations to drawing inferences from the majority of recent studies are threefold. First, transcranial Doppler ultrasound (TCD) has been widely used to evaluate CBF velocity (CBFV) [8][9][10][11]18,[20][21][22], which accurately represents CBF exclusively in the event that diameter of the insonated vessel remains constant. Whether this is the case with severe decreases or increases in MAP is unclear [23,24].…”

Section: Introductionmentioning

confidence: 99%

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Static autoregulation in humans: a review and reanalysis

Numan

Bain

Hoiland

et al. 2014

Medical Engineering & Physics

102

120

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Static autoregulation in humans: a review and reanalysis

Numan

Bain

Hoiland

et al. 2014

Medical Engineering & Physics

102

120

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“…A previous study (9) indicated that the response of V MCA during orthostatic stress simulated by LBNP was not different between fit and unfit older adults, because there was no change in V MCA observed in either group during steady-state LBNP (9). Based on previous observations (4,5,13,18,23,26,50), we postulated that there would be a cerebral hypoperfusion during upright or LBNP-simulated orthostatic stress in older subjects as a result of central hypovolemia and hyperventilation-elicited hypocapnia.The present study was designed to compare cerebral hemodynamic responses in relation to the change of systemic cardiovascular function during the challenge of mild to moderate LBNP between healthy sedentary elderly adults (SED group) and physically active elderly adults (ACT group). Although LBNP only simulates orthostasis, it allows graded changes in central blood volume without alteration of the hemodynamic reference point and isolates the cardiovascular responses without additional stimulus of the balance function or vestibular mechanism.…”

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confidence: 97%

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confidence: 97%

“…CEREBRAL HYPOPERFUSION, indicated by a decrease in middle cerebral arterial blood flow velocity (V MCA ), occurs with orthostasis-induced central hypovolemia during upright standing (10,11,14,18,20,23,40), head-up tilt (21,29,30,38), or lower body negative pressure (LBNP) (13,15,26,53). Deterioration of cerebral autoregulation or cerebral perfusion may be associated with orthostatic intolerance with or without pathophysiological conditions (14,15,20,29,53).…”

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confidence: 99%

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Chronic physical activity mitigates cerebral hypoperfusion during central hypovolemia in elderly humans

Formes

Zhang

Tierney

et al. 2010

American Journal of Physiology-Heart and Circulatory Physiology

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This study sought to test the hypothesis that orthostasis-induced cerebral hypoperfusion would be less severe in physically active elderly humans (ACT group) than in sedentary elderly humans (SED group). The peak O(2) uptake of 10 SED (67.1 +/- 1.4 yr) and 9 ACT (68.0 +/- 1.1 yr) volunteers was determined by a graded cycling exercise test (22.1 +/- 1.2 vs 35.8 +/- 1.3 ml.min(-1).kg(-1), P < 0.01). Baseline mean arterial pressure (MAP; tonometry) and middle cerebral arterial blood flow velocity (V(MCA); transcranial Doppler) were similar between the groups (SED vs. ACT group: 91 +/- 3 vs. 87 +/- 3 mmHg and 54.9 +/- 2.3 vs. 57.8 +/- 3.2 cm/s, respectively), whereas heart rate was higher and stroke volume (bioimpedance) was smaller in the SED group than in the ACT group. Central hypovolemia during graded lower body negative pressure (LBNP) was larger (P < 0.01) in the ACT group than in the SED group. However, the slope of V(MCA)/LBNP was smaller (P < 0.05) in the ACT group (0.159 +/- 0.016 cm/s/Torr) than in the SED group (0.211 +/- 0.008 cm/s/Torr). During LBNP, the SED group had a greater augmentation of cerebral vasomotor tone (P < 0.05) and hypocapnia (P < 0.001) compared with the ACT group. Baseline MAP variability and V(MCA) variability were significantly smaller in the SED group than in the ACT group, i.e., 0.49 +/- 0.07 vs. 1.04 +/- 0.16 (mmHg)(2) and 1.06 +/- 0.19 vs. 4.24 +/- 1.59 (cm/s)(2), respectively. However, transfer function gain, coherence, and phase between MAP and V(MCA) signals (Welch spectral estimator) from 0.08-0.18 Hz were not different between SED (1.41 +/- 0.18 cm.s(-1).mmHg(-1), 0.63 +/- 0.06 units, and 38.03 +/- 6.57 degrees ) and ACT (1.65 +/- 0.44 cm.s(-1).mmHg(-1), 0.56 +/- 0.05 units, and 48.55 +/- 11.84 degrees ) groups. We conclude that a physically active lifestyle improves the intrinsic mechanism of cerebral autoregulation and helps mitigate cerebral hypoperfusion during central hypovolemia in healthy elderly adults.

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Peripheral Circulation

Laughlin

Davis

Secher

et al. 2012

Comprehensive Physiology

211

234

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Blood flow (BF) increases with increasing exercise intensity in skeletal, respiratory, and cardiac muscle. In humans during maximal exercise intensities, 85% to 90% of total cardiac output is distributed to skeletal and cardiac muscle. During exercise BF increases modestly and heterogeneously to brain and decreases in gastrointestinal, reproductive, and renal tissues and shows little to no change in skin. If the duration of exercise is sufficient to increase body/core temperature, skin BF is also increased in humans. Because blood pressure changes little during exercise, changes in distribution of BF with incremental exercise result from changes in vascular conductance. These changes in distribution of BF throughout the body contribute to decreases in mixed venous oxygen content, serve to supply adequate oxygen to the active skeletal muscles, and support metabolism of other tissues while maintaining homeostasis. This review discusses the response of the peripheral circulation of humans to acute and chronic dynamic exercise and mechanisms responsible for these responses. This is accomplished in the context of leading the reader on a tour through the peripheral circulation during dynamic exercise. During this tour, we consider what is known about how each vascular bed controls BF during exercise and how these control mechanisms are modified by chronic physical activity/exercise training. The tour ends by comparing responses of the systemic circulation to those of the pulmonary circulation relative to the effects of exercise on the regional distribution of BF and mechanisms responsible for control of resistance/conductance in the systemic and pulmonary circulations.

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Effects of aging on the cerebrovascular orthostatic response

Cited by 26 publications

References 50 publications

Static autoregulation in humans: a review and reanalysis

Static autoregulation in humans: a review and reanalysis

Chronic physical activity mitigates cerebral hypoperfusion during central hypovolemia in elderly humans

Peripheral Circulation

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