Cardiovascular responses to water immersion in humans: impact on cerebral perfusion

Carter, Howard; Spence, Angela L.; Pugh, Christopher J. A.; Ainslie, Philip N.; Naylor, Louise H.; Green, Daniel

doi:10.1152/ajpregu.00516.2013

Cited by 66 publications

(90 citation statements)

References 40 publications

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“…), changes in conduit vessel diameter (Carter et al . b ), and increased arterial compliance (Boussuges, ). As such, we thought a true sham group which underwent chronic thermoneutral water immersion was necessary to isolate the effects of repeated rises in core temperature in the experimental group.…”

Section: Discussionmentioning

confidence: 99%

Passive heat therapy improves endothelial function, arterial stiffness and blood pressure in sedentary humans

Brunt

Howard

Francisco

et al. 2016

The Journal of Physiology

212

264

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Key pointsr A recent 30 year prospective study showed that lifelong sauna use reduces cardiovascular-related and all-cause mortality; however, the specific cardiovascular adaptations that cause this chronic protection are currently unknown.r We investigated the effects of 8 weeks of repeated hot water immersion ('heat therapy') on various biomarkers of cardiovascular health in young, sedentary humans.r We showed that, relative to a sham group which participated in thermoneutral water immersion, heat therapy increased flow-mediated dilatation, reduced arterial stiffness, reduced mean arterial and diastolic blood pressure, and reduced carotid intima media thickness, with changes all on par or greater than what is typically observed in sedentary subjects with exercise training.r Our results show for the first time that heat therapy has widespread and robust effects on vascular function, and as such, could be a viable treatment option for improving cardiovascular health in a variety of patient populations, particularly those with limited exercise tolerance and/or capabilities. AbstractThe majority of cardiovascular diseases are characterized by disorders of the arteries, predominantly caused by endothelial dysfunction and arterial stiffening. Intermittent hot water immersion ('heat therapy') results in elevations in core temperature and changes in cardiovascular haemodynamics, such as cardiac output and vascular shear stress, that are similar to exercise, and thus may provide an alternative means of improving health which could be utilized by patients with low exercise tolerance and/or capabilities. We sought to comprehensively assess the effects of 8 weeks of heat therapy on biomarkers of vascular function in young, sedentary subjects. Twenty young, sedentary subjects were assigned to participate in 8 weeks (4-5 times per week) of heat therapy (n = 10; immersion in a 40.5°C bath sufficient to maintain rectal temperature ࣙ 38.5°C for 60 min per session) or thermoneutral water immersion (n = 10; sham). Eight weeks of heat therapy increased flow-mediated dilatation from 5.6 ± 0.3 to 10.9 ± 1.0% (P < 0.01) and superficial femoral dynamic arterial compliance from 0.06 ± 0.01 to 0.09 ±0.01 mm 2 mmHg −1(P = 0.03), and reduced (i.e. improved) aortic pulse wave velocity from 7.1 ± 0.3 to 6.1 ± 0.3 m s −1(P = 0.03), carotid intima media thickness from 0.43 ± 0.01 to 0.37 ± 0.01 mm (P < 0.001), and mean arterial blood pressure from 83 ± 1 to 78 ± 2 mmHg (P = 0.02). No changes were observed in the sham group or for carotid arterial compliance, superficial femoral intima media thickness or endothelium-independent dilatation. Heat therapy improved endothelium-dependent dilatation, arterial stiffness, intima media thickness and blood pressure, indicating improved cardiovascular health. These data suggest heat therapy may provide a simple and effective tool for improving cardiovascular health in various populations.

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Section: Discussionmentioning

confidence: 99%

Passive heat therapy improves endothelial function, arterial stiffness and blood pressure in sedentary humans

Brunt

Howard

Francisco

et al. 2016

The Journal of Physiology

212

264

View full text Add to dashboard Cite

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“…suggested that an increase in middle cerebral artery blood velocity during water immersion is due to increases in blood pressure (Carter et al. ). However, they used a colder water temperature than we did (~30°C vs. ~35°C), which would likely cause differences in total peripheral resistance between studies.…”

Section: Discussionmentioning

confidence: 99%

“…The concomitant increase in PETCO 2 and cerebral perfusion suggests that a link between the two could exist during HOWI (Carter et al. ). However, it is not clear if the rise in cerebral perfusion during HOWI is due to acute hypercapnia or the combined effects of HOWI, including elevated PETCO 2 .…”

Section: Introductionmentioning

confidence: 99%

The effect of water immersion and acute hypercapnia on ventilatory sensitivity and cerebrovascular reactivity

et al. 2018

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The partial pressure of end tidal carbon dioxide (PETCO 2), ventilatory sensitivity to CO 2, and cerebral perfusion are augmented during thermoneutral head out water immersion (HOWI). We tested the hypotheses that HOWI and acute hypercapnia augments minute ventilation, ventilatory sensitivity to CO 2, cerebral perfusion, and cerebrovascular reactivity to CO 2. Twelve subjects (age: 24 ± 3 years, BMI: 25.3 ± 2.9 kg/m2, 6 women) participated in two experimental visits: a HOWI visit (HOWI) and a matched hypercapnia visit (Dry + CO 2). A rebreathing test was conducted at baseline, 10, 30, 60 min, and post HOWI and Dry + CO 2. PETCO 2, minute ventilation, expired gases, blood pressure, heart rate, and middle cerebral artery blood velocity were recorded continuously. PETCO 2 increased throughout HOWI (baseline: 42 ± 2 mmHg; maximum at 10 min: 44 ± 2 mmHg, P ≤ 0.013) and Dry + CO 2 (baseline: 42 ± 2 mmHg; maximum at 10 min: 44 ± 2 mmHg, P ≤ 0.013) and was matched between conditions (condition main effect: P = 0.494). Minute ventilation was lower during HOWI versus Dry + CO 2 (maximum difference at 60 min: 13.2 ± 1.9 vs. 16.2 ± 2.7 L/min, P < 0.001). Ventilatory sensitivity to CO 2 and middle cerebral artery blood velocity were greater during HOWI versus Dry + CO 2 (maximum difference at 10 min: 2.60 ± 1.09 vs. 2.20 ± 1.05 L/min/mmHg, P < 0.001, and 63 ± 18 vs. 53 ± 14 cm/sec, P < 0.001 respectively). Cerebrovascular reactivity to CO 2 decreased throughout HOWI and Dry + CO 2 and was not different between conditions (condition main effect: P = 0.777). These data indicate that acute hypercapnia, matched to what occurs during HOWI, augments minute ventilation but not ventilatory sensitivity to CO 2 or middle cerebral artery blood velocity despite an attenuated cerebrovascular reactivity to CO 2.

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“…Recently this concept has been illustrated via water immersion, where CBF increases in a similar magnitude to that obtained during landbased exercise, 128 and more so when water immersion was combined with exercise. 129 How this then translates to longerterm effects (i.e., after a training intervention) has not yet been reported, but the combined strategy may result in greater improvements in cerebrovascular function than previously reported from a standard land-and aerobic-based training study.…”

Section: Optimizing Cerebrovascular Adaptation Through Brain-targetedmentioning

confidence: 93%

High-Intensity Interval Exercise and Cerebrovascular Health: Curiosity, Cause, and Consequence

Lucas

Cotter

Brassard

et al. 2015

J Cereb Blood Flow Metab

162

179

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Exercise is a uniquely effective and pluripotent medicine against several noncommunicable diseases of westernised lifestyles, including protection against neurodegenerative disorders. High-intensity interval exercise training (HIT) is emerging as an effective alternative to current health-related exercise guidelines. Compared with traditional moderate-intensity continuous exercise training, HIT confers equivalent if not indeed superior metabolic, cardiac, and systemic vascular adaptation. Consequently, HIT is being promoted as a more time-efficient and practical approach to optimize health thereby reducing the burden of disease associated with physical inactivity. However, no studies to date have examined the impact of HIT on the cerebrovasculature and corresponding implications for cognitive function. This review critiques the implications of HIT for cerebrovascular function, with a focus on the mechanisms and translational impact for patient health and well-being. It also introduces similarly novel interventions currently under investigation as alternative means of accelerating exercise-induced cerebrovascular adaptation. We highlight a need for studies of the mechanisms and thereby also the optimal dose-response strategies to guide exercise prescription, and for studies to explore alternative approaches to optimize exercise outcomes in brain-related health and disease prevention. From a clinical perspective, interventions that selectively target the aging brain have the potential to prevent stroke and associated neurovascular diseases.

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Cardiovascular responses to water immersion in humans: impact on cerebral perfusion

Cited by 66 publications

References 40 publications

Passive heat therapy improves endothelial function, arterial stiffness and blood pressure in sedentary humans

Passive heat therapy improves endothelial function, arterial stiffness and blood pressure in sedentary humans

The effect of water immersion and acute hypercapnia on ventilatory sensitivity and cerebrovascular reactivity

High-Intensity Interval Exercise and Cerebrovascular Health: Curiosity, Cause, and Consequence

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