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1.
Head-out immersion in hot water increases serum BDNF in healthy males.
Kojima, D, Nakamura, T, Banno, M, Umemoto, Y, Kinoshita, T, Ishida, Y, Tajima, F
International journal of hyperthermia : the official journal of European Society for Hyperthermic Oncology, North American Hyperthermia Group. 2018;(6):834-839
Abstract
PURPOSE Brain-derived neurotrophic factor (BDNF) is an important neurotrophin. The present study investigated the effects of head-out water immersion (HOI) on serum BDNF concentrations. METHODS Eight healthy men performed 20 min head-out water immersion at 42 °C (hot-HOI) and 35 °C (neutral-HOI). These experimental trials were administered in a randomised order separated by at least 7 days. Venous blood samples were withdrawn at rest, immediately after the 20-min HOI, as well as at 15 and 30 min after the end of the HOI. Serum BDNF and S100β, plasma cortisol, platelet and monocyte counts, and core body temperature (Tcb) were measured. RESULTS Tcb was higher at the end of the hot-HOI and 15 min after hot-HOI (p < 0.01), but recovered to pre-HOI level at 30 min after hot-HOI. No change in Tcb was recorded during neutral-HOI. BDNF level was higher (p < 0.05) at the end of the hot-HOI and at 15 min after the end of hot-HOI, and returned to the baseline at 30 min after hot-HOI. S100β, platelet count and monocyte count remained stable throughout the study. Cortisol level was lower at the end of the hot-HOI and returned to pre-HOI level during the recovery period. BDNF and S100β, cortisol, and platelet and monocyte counts did not change throughout the neutral-HOI study. CONCLUSIONS The present findings suggested that the increase in BDNF during 20-min hot-HOI was induced by hyperthermia through enhanced production, rather than by changes in permeability of the blood-brain barrier (BBB), platelet clotting mechanisms or secretion from monocytes.
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Treadmill walking in water induces greater respiratory muscle fatigue than treadmill walking on land in healthy young men.
Yamashina, Y, Yokoyama, H, Naghavi, N, Hirasawa, Y, Takeda, R, Ota, A, Imai, D, Miyagawa, T, Okazaki, K
The journal of physiological sciences : JPS. 2016;(3):257-64
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Abstract
The purpose of the present study was to investigate the effect of walking in water on respiratory muscle fatigue compared with that of walking on land at the same exercise intensity. Ten healthy males participated in 40-min treadmill walking trials on land and in water at an intensity of 60% of peak oxygen consumption. Respiratory function and respiratory muscle strength were evaluated before and after walking trials. Inspiratory muscle strength and forced expiratory volume in 1 s were significantly decreased immediately after walking in water, and expiratory muscle strength was significantly decreased immediately and 5 min after walking in water compared with the baseline. The decreases of inspiratory and expiratory muscle strength were significantly greater compared with that after walking on land. In conclusion, greater inspiratory and expiratory muscle fatigue was induced by walking in water than by walking on land at the same exercise intensity in healthy young men.
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Use of Cold-Water Immersion to Reduce Muscle Damage and Delayed-Onset Muscle Soreness and Preserve Muscle Power in Jiu-Jitsu Athletes.
Fonseca, LB, Brito, CJ, Silva, RJ, Silva-Grigoletto, ME, da Silva, WM, Franchini, E
Journal of athletic training. 2016;(7):540-9
Abstract
CONTEXT Cold-water immersion (CWI) has been applied widely as a recovery method, but little evidence is available to support its effectiveness. OBJECTIVE To investigate the effects of CWI on muscle damage, perceived muscle soreness, and muscle power recovery of the upper and lower limbs after jiu-jitsu training. DESIGN Crossover study. SETTING Laboratory and field. PATIENTS OR OTHER PARTICIPANTS A total of 8 highly trained male athletes (age = 24.0 ± 3.6 years, mass = 78.4 ± 2.4 kg, percentage of body fat = 13.1% ± 3.6%) completed all study phases. INTERVENTION(S): We randomly selected half of the sample for recovery using CWI (6.0°C ± 0.5°C) for 19 minutes; the other participants were allocated to the control condition (passive recovery). Treatments were reversed in the second session (after 1 week). MAIN OUTCOME MEASURE(S): We measured serum levels of creatine phosphokinase, lactate dehydrogenase (LDH), aspartate aminotransferase, and alanine aminotransferase enzymes; perceived muscle soreness; and recovery through visual analogue scales and muscle power of the upper and lower limbs at pretraining, postrecovery, 24 hours, and 48 hours. RESULTS Athletes who underwent CWI showed better posttraining recovery measures because circulating LDH levels were lower at 24 hours postrecovery in the CWI condition (441.9 ± 81.4 IU/L) than in the control condition (493.6 ± 97.4 IU/L; P = .03). Estimated muscle power was higher in the CWI than in the control condition for both upper limbs (757.9 ± 125.1 W versus 695.9 ± 56.1 W) and lower limbs (53.7 ± 3.7 cm versus 35.5 ± 8.2 cm; both P values = .001). In addition, we observed less perceived muscle soreness (1.5 ± 1.1 arbitrary units [au] versus 3.1 ± 1.0 au; P = .004) and higher perceived recovery (8.8 ± 1.9 au versus 6.9 ± 1.7 au; P = .005) in the CWI than in the control condition at 24 hours postrecovery. CONCLUSIONS Use of CWI can be beneficial to jiu-jitsu athletes because it reduces circulating LDH levels, results in less perceived muscle soreness, and helps muscle power recovery at 24 hours postrecovery.
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The effect of different water immersion temperatures on post-exercise parasympathetic reactivation.
de Oliveira Ottone, V, de Castro Magalhães, F, de Paula, F, Avelar, NC, Aguiar, PF, da Matta Sampaio, PF, Duarte, TC, Costa, KB, Araújo, TL, Coimbra, CC, et al
PloS one. 2014;(12):e113730
Abstract
PURPOSE We evaluated the effect of different water immersion (WI) temperatures on post-exercise cardiac parasympathetic reactivation. METHODS Eight young, physically active men participated in four experimental conditions composed of resting (REST), exercise session (resistance and endurance exercises), post-exercise recovery strategies, including 15 min of WI at 15°C (CWI), 28°C (TWI), 38°C (HWI) or control (CTRL, seated at room temperature), followed by passive resting. The following indices were assessed before and during WI, 30 min post-WI and 4 hours post-exercise: mean R-R (mR-R), the natural logarithm (ln) of the square root of the mean of the sum of the squares of differences between adjacent normal R-R (ln rMSSD) and the ln of instantaneous beat-to-beat variability (ln SD1). RESULTS The results showed that during WI mRR was reduced for CTRL, TWI and HWI versus REST, and ln rMSSD and ln SD1 were reduced for TWI and HWI versus REST. During post-WI, mRR, ln rMSSD and ln SD1 were reduced for HWI versus REST, and mRR values for CWI were higher versus CTRL. Four hours post exercise, mRR was reduced for HWI versus REST, although no difference was observed among conditions. CONCLUSIONS We conclude that CWI accelerates, while HWI blunts post-exercise parasympathetic reactivation, but these recovery strategies are short-lasting and not evident 4 hours after the exercise session.
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Cardiovascular and autonomic responses to physiological stressors before and after six hours of water immersion.
Florian, JP, Simmons, EE, Chon, KH, Faes, L, Shykoff, BE
Journal of applied physiology (Bethesda, Md. : 1985). 2013;(9):1275-89
Abstract
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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Human face-only immersion in cold water reduces maximal apnoeic times and stimulates ventilation.
Jay, O, Christensen, JP, White, MD
Experimental physiology. 2007;(1):197-206
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Abstract
In two studies, the cold shock and diving responses were investigated after human face immersion without prior hyperventilation to explore the mechanism(s) accounting for reductions in maximal apnoeic times (ATmax) at low water temperatures. In study 1, ATmax, heart rate (HR) and cutaneous blood cell velocity were measured in 13 non-apnoea-trained males during apnoeic face immersion in 0, 10, 20 and 33 degrees C water and room air (AIR). In study 2, six males were measured during non-apnoeic face immersion in 0, 10 and 33 degrees C water for ventilation (VE), respiratory exchange ratio (RER), HR and oxygen consumption (VO2), as well for end-tidal partial pressures of oxygen (PET,O2) and carbon dioxide (PET,CO2). Results indicated that the ATmax of 30.7 s (S.D. 7.1 s) at 0 degrees C (P < 0.001) and 48.2 s (S.D. 16.0 s) at 10 degrees C (P < 0.05) were significantly shorter than that of 58 s in AIR or 33 degrees C. During apnoea at 0, 10, 20 and 33 degrees C, both the deceleration of HR (P < 0.05) and peripheral vasoconstriction (P < 0.05), as well as the peak HR at 0 degrees C (P = 0.002) were significantly greater than in AIR. At 0 degrees C in comparison with 33 degrees C, non-apnoeic face immersions gave peaks in (P = 0.039), RER (P = 0.025), (P = 0.032) and HR (P = 0.011), as well as lower minimum values for (P = 0.033) and HR (P = 0.002). With as the covariate, ANCOVA showed that remained significantly greater (P = 0.003) at lower water temperatures. In conclusion, during face immersion at 10 degrees C and below, there is a non-metabolic, neurally mediated cold shock-like response that shortens apnoea, stimulates ventilation and predominates over the oxygen conserving effects of the dive response.
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Effects of hyperoxia on thermoregulatory responses during feet immersion to hot water in humans.
Yamashita, K, Tochihara, Y
Journal of physiological anthropology and applied human science. 2003;(4):181-5
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Abstract
This study examined effects of hyperoxia on thermoregulatory responses. Eight healthy male students (23.5+/-1.8 yrs) were involved in this study. They immersed their legs in a hot water bath (42 degrees C) for 60 minutes in a climate chamber. The conditions of oxygen concentration of a chamber were set at 21% (control), 25% (25%O(2)), and 30% (30%O(2)). Ambient temperature and relative humidity was maintained at 25 degrees C and 50% in every condition, respectively. Measurements included rectal temperature (Tre), skin temperature at 7 sites, laser Doppler flowmeter (LDF) on the back and forearm as an index of skin blood flow, heart rate, local sweat rate (Msw) on the back and forearm, and total body weight loss (BWL). Increases of Tre at 25%O(2) and 30%O(2) tended to be lower during the immersion than in the control. Mean skin temperature (Tsk) of the control increased gradually after the onset of sweating, while the Tsks at 25%O(2) and 30%O(2) maintained a constant level during sweating. LDFs on the forearm at 25%O(2) and 30%O(2) showed lower increases compared with the control. No significant differences in Msw on the back and the forearm and BWL were seen among the conditions. These results suggested that hyperoxia could not affect sweating responses but elicit an inhibitory effect on thermoregulatory skin blood flow.
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Does gender influence human cardiovascular and renal responses to water immersion?
Watenpaugh, DE, Pump, B, Bie, P, Norsk, P
Journal of applied physiology (Bethesda, Md. : 1985). 2000;(2):621-8
Abstract
We hypothesized that women and men exhibit similar cardiovascular and renal responses to thermoneutral water immersion (WI) to the neck. Ten women and nine men underwent two sessions in random order: 1) seated nonimmersed for 5.5 h (control) and 2) WI for 3 h, with subjects seated nonimmersed for 1.5 h pre- and 1 h postimmersion. We measured left atrial diameter, heart rate, arterial pressure, urine volume and osmolality, and urinary endothelin, urodilatin, sodium, and potassium excretion. No significant difference existed between groups in cardiovascular responses. The groups also exhibited mostly similar renal responses to immersion after adjustment for body mass. However, female urodilatin excretion per kilogram during immersion was over twofold that of men, and the female kaliuretic response to immersion was delayed and less pronounced relative to that in men. Men may excrete more potassium than women during immersion because men possess greater lean body mass (potassium per kilogram). Results obtained in men during WI may be cautiously extrapolated to women, yet urodilatin and potassium responses exhibit gender differences.