Effect of physical fitness and training on physiological responses to hypogravity

Saiki, H.; Nakaya, M; Sudoh, Masamichi; Abé, Masakazu; Taketomi, Yoshio; Ohishi, Kenji; Saiki, Yoshikatsu; Saiki, Ayako

doi:10.1016/0094-5765(81)90066-7

Cited by 3 publications

(1 citation statement)

References 4 publications

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“…Physiological responses to WI may reduce physical performance and orthostatic tolerance after egress from the water (22,54,58). Indeed, the release of hydrostatic pressure following WI elicits acute hypovolemia (46,48), and post-WI physiological responses in several reports indicate modulation of autonomic function (38,46,54) and changes in cardiac or vascular function (3,4,11). After WI, resting HR and BP remain unchanged compared with pre-WI values (4,46) and Q is unchanged (46,57) or reduced (4).…”

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Cardiovascular and autonomic responses to physiological stressors before and after six hours of water immersion

Florian

Simmons

Chon

et al. 2013

Journal of Applied Physiology

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The physiological responses to water immersion (WI) are known; however, the responses to stress following WI are poorly characterized. Ten healthy men were exposed to three physiological stressors before and after a 6-h resting WI (32-33°C): 1) a 2-min cold pressor test, 2) a static handgrip test to fatigue at 40% of maximum strength followed by postexercise muscle ischemia in the exercising forearm, and 3) a 15-min 70° head-up-tilt (HUT) test. Heart rate (HR), systolic and diastolic blood pressure (SBP and DBP), cardiac output (Q), limb blood flow (BF), stroke volume (SV), systemic and calf or forearm vascular resistance (SVR and CVR or FVR), baroreflex sensitivity (BRS), and HR variability (HRV) frequency-domain variables [low-frequency (LF), high-frequency (HF), and normalized (n)] were measured. Cold pressor test showed lower HR, SBP, SV, Q, calf BF, LFnHRV, and LF/HFHRV and higher CVR and HFnHRV after than before WI (P < 0.05). Handgrip test showed no effect of WI on maximum strength and endurance and lower HR, SBP, SV, Q, and calf BF and higher SVR and CVR after than before WI (P < 0.05). During postexercise muscle ischemia, HFnHRV increased from baseline after WI only, and LFnHRV was lower after than before WI (P < 0.05). HUT test showed lower SBP, DBP, SV, forearm BF, and BRS and higher HR, FVR, LF/HFHRV, and LFnHRV after than before WI (P < 0.05). The changes suggest differential activation/depression during cold pressor and handgrip (reduced sympathetic/elevated parasympathetic) and HUT (elevated sympathetic/reduced parasympathetic) following 6 h of WI.

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confidence: 99%

Cardiovascular and autonomic responses to physiological stressors before and after six hours of water immersion

Florian

Simmons

Chon

et al. 2013

Journal of Applied Physiology

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Site Specificity of Changes in Cortical Oxyhaemoglobin Concentration Induced by Water Immersion

Sato

Yamashiro

Yamazaki

et al. 2017

Advances in Experimental Medicine and Biology

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Our previous studies have shown that water immersion (WI) changes sensorimotor processing and cortical excitability in the sensorimotor regions of the brain. The present study examined the site specificity of the brain activation during WI using functional near infrared spectroscopy (fNIRS). Cortical oxyhaemoglobin (OHb) levels in the anterior and posterior parts of the supplementary motor area (pre-SMA and SMA), primary motor cortex (M1), primary somatosensory cortex (S1), and posterior parietal cortex (PPC) were recorded using fNIRS (OMM-3000; Shimadzu Co.) before, during, and after WI in nine healthy participants. The cortical OHb levels in SMA, M1, S1, and PPC significantly increased during the WI and increased gradually along with the filling of the WI tank. These changes were not seen in the pre-SMA. The results show that WI-induced increases in cortical OHb levels are at least somewhat site specific: there was little brain activation in response to somatosensory input in the pre-SMA, but robust activation in other areas.

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Polyimides

Sroog

1991

Progress in Polymer Science

802

249

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Effect of physical fitness and training on physiological responses to hypogravity

Cited by 3 publications

References 4 publications

Cardiovascular and autonomic responses to physiological stressors before and after six hours of water immersion

Cardiovascular and autonomic responses to physiological stressors before and after six hours of water immersion

Site Specificity of Changes in Cortical Oxyhaemoglobin Concentration Induced by Water Immersion

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