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PubMed2003

Water immersion and EMLA cause similar digit skin wrinkling and vasoconstriction.

Water immersion skin wrinkling tests limb sympathetic vasoconstrictor function. We have recently shown that water immersion wrinkling is accompanied by digit vasoconstriction and postulated that vasoconstriction is the main underlying mechanism. To test this further, we applied vasoconstrictive cream (EMLA) to the distal digit and compared the degree of skin wrinkling and digit blood flow reduction with those after water immersion. In 25 healthy volunteers (6 male, 19 female; mean age, 35 yr) subjected to EMLA and water immersion, both clinical wrinkling scores and reduction in digit blood flow (mean of 2.01 and 2.29 cm/s, respectively) were nearly identical. Control using aqueous cream resulted in minimal skin wrinkling and nonsignificant reduction in digit artery flow (P = 0.170). These data further support that water immersion skin wrinkling is mediated by vasoconstriction. The EMLA cream patch test may develop into a useful screening test for hand sympathetic vasoconstrictor function.

Adult↗
PubMed1977

Neurological and phychometric studies in children surviving freshwater immersion accidents.

A study of the neurological and intellectual sequelae of childhood near-drowning is reported. Results are from a total population study, without selection, of all freshwater immersion accidents in which consciousness was lost in the water. Such accidents affected 56 children in the city of Brisbane and environs over the period 1971-75. 54 of these children have been re-examined medically and psychometrically. Over 95 per cent of children who survived such accidents were neurologically normal. The median i.q. of survivors was 110 (range 90-137), which is higher than that of the general population. There is a suggestion that visualmotor (performance)) skills are particularly vulnerable to freshwater immersion hypoxia. In 20 per cent of survivors subscale disparities between verbal and performance skills exceeded 15 i.q. points. No correlation between the post-immersion I.Q. and either estimated immersion-time or water temperature was demonstrated in this study. No long-term emotional or personality disorders were encountered. Uncommon gross clinical sequelae of prolonged immersion in fresh water included spastic quadriplegia and gross mental retardation. All children in this study were apparently dead at the moment of rescue; despite this, the prognosis of near-drowning in childhood is excellent

Child↗
PubMed1999

Influence of immersion on respiratory requirements during 30-min cycling exercise.

Immersion is considered to facilitate exercise-based rehabilitation. However, the drag effect of moving limbs in water, likely to increase the respiratory requirements at exercise, is not mentioned in many reports. The energetic and ventilatory requirements of 30 min steady state cycling exercise performed by healthy male subjects in air and during immersion up to the xiphoid in 33 degrees C water were compared. In the first experimental series nine subjects exercised at the same 60% maximal oxygen consumption (V'O2,max) in air and water. In the two ambient conditions, ventilatory variables had similar values, but the ergometric setting had to be reduced during water immersion so that the workload rated only 69+/-20 W (mean+/-SD) in water versus 121+/-32 W (p<0.001) in air. In the second experimental series, the same ergometric work load (122 W) was achieved by nine subjects with an average V'O2 of 2,210+/-300 mL x min(-1) in air versus 2,868+/-268 mL x min(-1) in water (p<0.001). Resting water immersion caused a marked trend for decreasing vital capacity (p=0.06), but no modification of other ventilatory variables. During exercise at similar V'O2, the average values of minute ventilation (V'E), tidal volume (VT), respiratory frequency (fR), tidal inspiratory time (VT/tI) were not different between water and air. However, at similar ergometric workload, V'E, VT, fR, VT/tI and plasma lactate levels were significantly higher in water than in air. Such consequences of the drag effect of water upon limb movements have not been reported in previous studies relying on shorter exercise bouts. Thus, maintaining steady exercise levels in water either led to a decrease in the workload or required a 25% higher oxygen consumption than in air. These findings may be relevant to the prescription of water immersion rehabilitation programmes.

Adult↗
PubMed1986

Factors determining renal response to water immersion in non-excretor cirrhotic patients.

Non-excretor cirrhotic patients, defined by their inability to normally excrete a standard water load, display variable responses to head-out water immersion. The hemodynamic, hormonal, and renal functional status of fifteen such patients were analyzed relative to water excretion during head-out water immersion. Group 1 patients (N = 7) all excreted less than 40% of the water load during immersion, whereas excretion was greater than 40% in all eight patients in Group 2. Group 1 patients, when compared with Group 2, had more ascites, more diuretic resistance, lower serum sodium concentration (125 +/- 2 vs. 130 +/- 1 mEq/liter, P less than 0.05), and more impaired baseline water excretion (12.9 +/- 1.2 vs. 35.9 +/- 5.9% of water load in 5 hr, P less than 0.005). Systemic hemodynamic responses to water immersion were similar in both groups. Glomerular filtration rate and renal plasma flow were significantly more impaired in Group 1 patients (inulin clearance 28 +/- 6 vs. 62 +/- 9 ml/min/1.73 m2, P less than 0.05; para-aminohippurate clearance 212 +/- 35 vs. 357 +/- 37 ml/min, P less than 0.05). Concentrations of plasma vasopressin (1.7 +/- 0.5 vs. 0.8 +/- 0.1 pg/ml, P less than 0.05), renin (8.6 +/- 1.7 vs. 3.8 +/- 0.9 ng/ml/hr, P less than 0.05), aldosterone (82 +/- 14 vs. 39 +/- 10 ng/dl, P less than 0.05) and norepinephrine (1155 +/- 183 vs. 603 +/- 126 pg/ml, P less than 0.05) were all significantly higher in Group 1 than Group 2 patients during water immersion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1996

Implication of nitric oxide synthase activity in the genesis of water immersion stress-induced gastric lesions in rats: the protective effects of FK506.

BACKGROUND: Nitric oxide (NO) is a potent cytoprotective substance of gastric mucosa. FK506, an immunosuppressive drug, shows anti-gastric ulcer effects equivalent to famotidine, an H2 blocker, in rats. This study was designed to evaluate the cytoprotective mechanism of FK506 on gastric mucosa in relation to the changes in NO synthase activity. METHODS: Gastric lesions were induced in rats by water immersion stress. Changes in NO synthase activity during water immersion stress treatment, and effects of FK506 on NO synthase activity were determined enzymatically. Gastric mucosal interleukin (IL)-1 beta and IL-2 were measured by immunoradiometric assay. Gastric mucosal blood flow was measured by hydrogen gas clearance technique. RESULTS: FK506 mitigated gastric lesions developed by water immersion stress. Stress-induced lesions were exacerbated by NG-monomethyl-L-arginine (L-NMMA), a specific inhibitor of NO synthase, while sodium nitroprusside, a NO donor, mitigated the lesions. Water immersion stress increased NO synthase activity in the early phase (0.5 h after stress treatment) and decreased it in the late phase (6 h after). Decrease in NO synthase activity in the late phase was significantly mitigated by FK506, though it did not affect changes in NO synthase activity in the early phase. Water immersion stress increased gastric mucosal IL-1 beta and IL-2 contents 6 h after stress treatment, and these increases were prevented by FK506. FK506 itself did not affect gastric mucosal blood flow. L-NMMA treatment significantly decreased gastric mucosal blood flow. In contrast, gastric mucosal blood flow was significantly increased by sodium nitroprusside. CONCLUSIONS: Increase in NO synthase activity might contribute to cytoprotection, and a decrease in activity might be a harmful factor for the gastric mucosa. Preservation of NO synthase activity by FK506 might be involved in FK506's protective effects on the gastric mucosa.

Animals↗
PubMed1981

Effect of saline solution immersion on corneal scattering characteristics.

The scattering characteristics of the cornea were measured during immersion in various saline concentrations. Initially, scattering was monitored subjectively by spatial frequency thresholds and contrast thresholds on sine wave grids, and by the border enhancement method. Although all three methods responded to corneal scattering changes produced during immersion, the latter method proved to be the most sensitive. The border enhancement method was subsequently applied during immersion of the cornea in various hypotonic and hypertonic saline solutions. Scattering changes were recorded during an immersion period of 1 hr followed by a recovery period of 1/2 hr. As expected, the scattering increased with hypotonicity. However, certain features of the time characteristics of the scattering changes suggest that the effect of the immersion fluid is modified by the tear flow.

Cornea↗
PubMed1995

Relative contributions of voluntary apnoea, exposure to cold and face immersion in water to diving bradycardia in humans.

1. Diving or face immersion bradycardia is a well recognized but incompletely understood reflux which occurs in man and other mammals. 2. In order to investigate the contributions made by voluntary apnoea, face immersion in water and cold exposure, 18 normal subjects were exposed to these challenges separately and in various combination. 3. Tested individually, cold and apnoea caused significant reductions in heart beat (P < 0.01 and 0.002, respectively). Face immersion in thermoneutral water had no effect on heart rate. 4. The bradycardic effect of apnoea at maximal inspiration may be due to stimulation of pulmonary stretch receptors. 5. Cold exposure and voluntary apnoea applied simultaneously caused a summative effect but when tested with face immersion in water there was a synergistic response greater than the sum of individual responses. 6. The results confirm the bradycardic effect of apnoea and cold exposure, whereas immersion in thermoneutral water had little effect, a finding which has been disputed in the literature.

Adult↗
PubMed2006

Human face-only immersion in cold water reduces maximal apnoeic times and stimulates ventilation.

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.

Adult↗
PubMedDate not supplied

Observations on the effect of immersion in Bath spa water.

Immersion in water in spas has been practised for centuries and has many proponents. Despite fierce debate about its efficacy there has been little scientific evaluation of the effect of immersion in mineral waters. Eight normal subjects were immersed in Bath spa water for two hours and the renal, haematological, and cardiovascular responses were compared with those in the control periods before and after immersion. Significant, twofold diuresis and natriuresis, 5% haemodilution, and a 50% increase in cardiac index were observed in subjects immersed, sitting, in Bath spa water at 35 degrees C. These changes may constitute part of the scientific rationale for spa treatment in many states of disease.

Adult↗
PubMed1986

Thermal and metabolic adaptation to first cold-water immersion in juvenile penguins.

Juvenile king and macaroni penguins are terrestrial seabirds and must face an intensive and prolonged energetic demand during their passage from shore to marine life in cold subantarctic seawater. Evidence for progressive thermal adaptation was sought by measurement of metabolic rate (MR) and body (Tb) and skin (Tsk) temperatures in unrestrained, fully immersed penguins. Steady-state responses obtained after the 3rd h of immersion in never-immersed (NI) penguins were compared with those of penguins acclimatized to seawater temperature (A). NI macaroni penguins, unlike NI king penguins, showed a fall in Tb on their first immersion but, once acclimatized, were able to maintain their homeothermy due to an increase (greater than 3.2 W/kg) in regulatory thermogenesis. In NI king penguins, during a simulation of seawater adaptation by 10 successive immersions, MR at 7 degrees C water temperature (Tw) rose from 6.0 to 9.4 W/kg (becoming 3-5 times higher than in air), whereas Tb rose from 37.6 to 38.4 degrees C. In both species occurrence of peak MR at much lower Tw, progressive increase in thermogenesis capacity, and lower conductance in water after adaptation to marine life (28 and 36% less in A king and macaroni penguins, respectively) showed that the passage from shore to marine life consisted of a true cold acclimatization.

Acclimatization↗
PubMed1992

Human thermoregulatory responses during cold water immersion after artificially induced sunburn.

Thermoregulatory responses during cold-water immersion (water temperature 22 degrees C) were compared in 10 young men before as well as 24 h and 1 wk after twice the minimal erythemal dose of ultraviolet-B radiation that covered approximately 85% of the body surface area. After 10 min of seated rest in cold water, the mean exercised for 50 min on a cycle ergometer (approximately 51% of maximal aerobic power). Rectal temperature, regional and mean heat flow (hc), mean skin temperature from five sites, and hearrt rate were measured continuously for all volunteers while esophageal temperature was measured for six subjects. Venous blood samples were collected before and after cold water immersion. The mean skin temperature was higher (P less than 0.05) throughout the 60-min cold water exposure both 24 h and 1 wk after sunburn compared with before sunburn. Mean hc was higher (P less than 0.05) after 10 min resting immersion and during the first 10 min of exercise when 24 h postsunburn was compared with presunburn, with the difference attributed primarily to higher hc from the back and chest. While rectal temperature and heart rate did not differ between conditions, esophageal temperature before immersion and throughout the 60 min of cold water immersion was higher (P less than 0.05) when 24 h postsunburn was compared with presunburn. Plasma volume increased (P less than 0.05) after 1 wk postsunburn compared with presunburn, whereas plasma protein concentration was reduced (P less than 0.05). After exercise cortisol was greater (P less than 0.05) 24 h postsunburn compared with either presunburn or 1 wk postsunburn.(ABSTRACT TRUNCATED AT 250 WORDS)

Body Temperature↗
PubMed1975

Expiratory reserve volume and vital capacity of the lungs during immersion in water.

The effects of immersion by 5-cm increments on the expiratory reserve volume of the lungs (ERV) and on the vital capacity were studied in the sitting and supine positions. These effects were compared to those produced by continuous negative-pressure breathing when the subjects were in air and were counteracted by positive pressure breathing during immersion. The depth of immersion was also related to definable anatomic landmarks. In the sitting position about one-fourth of the decrease in the ERV was accounted for by the hydrostatic pressure of the water on the abdomen and the remainder by the pressure on the thorax. Immersion to the level of the spinous process of the seventh cervical vertebra was equivalent to 28 cmH2o continuous negative pressure breathing in air. In the supine position, a comparable value was 8 cmH2o. These observations agree well with those of others if differences in the levels of immersion are accounted for.

Abdomen↗
PubMed1977

Alcohol, respiration, skin and body temperature during cold water immersion.

Subjects who had not been exercising, were immersed for 20 min in water at 13 degrees C after ingestion of alcohol. During the immersion period, total ventilation, end-tidal PCO2, rectal temperature, aural temperature, and mean skin temperature were recorded. Control experiments were carried out at the same water temperature. Blood samples (3 ml), taken immediately before the immersion period, were analyzed by gas liquid chromatography. The mean blood alcohol level was 90+/-11.2 mg-(100 ml)-1. There was no significant difference in ventilatory responses, rectal temperatures, aural temperatures, or mean skin temperatures achieved during the two cold water immersions. It would appear that for a 20-min immersion at 13 degrees C, relatively high blood alcohol levels do not affect ventilatory responses or increase body heat losses.

Alcohol Drinking↗
PubMed1979

Fluid shifts during initial phase of immersion diuresis in man.

The object was to study fluid shifts in man during the 1st h of immersion diuresis. Control experiments were done on subjects lying down in air for 4 h with and without vasopressin. During immersion up to the neck, seven of nine subjects had significant diuresis and natriuresis. In the first 20 min of sitting in 33 degress C water, a hemodilution of 2% of blood volume was observed. As diuresis progressed, hemoconcentration began. When vasopressin was given just before immersion to prevent the diuresis, the hemodilution observed was greater and lasted longer. Thus the hematocrit fell by 1.7 U, plasma osmolality by 6.0 mosmol/kg, plasma proteins by 0.33 g/100 ml, and plasma sodium by 5.0 meq/l. We conclude that a hemodilution of about 4% of blood volume occurs during the early plasma of immersion and the degree of hyposmolality observed suggests that the fluid shifted was more hyposmotic than the interstitial fluid alone, possibly because some intracellular water may have shifted into the bloodstream during immersion.

Diuresis↗
PubMed1983

Hypervolemia and plasma vasopressin response during water immersion in men.

To investigate changes in plasma volume (PV) and osmolality as stimuli for plasma vasopressin (PVP) suppression and diuresis, seven normal healthy men (22-48 yr) were immersed to the neck for 4 h in a sitting position in tap water (34.5 degrees C) after overnight food and fluid restriction. Mean +/- SE urine volume was 823 +/- 123 ml/4 h; fluid intake was 400 ml/4 h, and mean negative water balance was 944 ml/4 h. Urinary sodium excretion increased from 0.77 to 1.25 mosmol/min (P less than 0.05) and UNaV from 0.14 to 0.37 meq/min (P less than 0.05). During immersion, PV (T-1824) increased by 8.8% (P less than 0.05) during the first 30 min and declined linearly thereafter. Mean +/- SD serum osmolality (294 +/- 1.2 mosmol/kg H2O) and sodium (143.2 +/- 0.4 meq/l) were constant throughout immersion; PVP (2.3 +/- 0.5 pg/ml) and plasma renin activity [0.3 +/- 0.2 ng ANG I/(ml X h]) were not significantly changed. Thus, the composition of the fluid entering the vascular space maintained constant serum osmolality and PVP throughout immersion. These findings do not support the hypothesis that acute expansion of central volume and PV cause suppression of PVP. The results suggest a mechanism other than or in addition to PVP suppression as a contributory cause of the immersion diuresis.

Adult↗
PubMed1987

Detailed characterization of a tank used for head-out water immersion in humans.

Water immersion has long been known to produce marked diuresis, natriuresis, and kaliuresis and suppression of the renin-aldosterone system. These effects are mediated primarily by an increase in central blood volume. Immersion has therefore gained increased acceptance in human physiology for the investigation of the effects of central volume expansion on renal function and hormonal responsiveness without altering the composition of the extracellular fluid. An immersion tank used for studies in humans is described. Requisite features to ensure study reproducibility include a constant temperature, capability to alter the depth of immersion by adjusting water height, and the ability to maintain hygienic quality by means of constant circulation of the water through a sand filter. A constant temperature of 34.5 +/- 0.2 degrees C is maintained by thermostatically controlling the heat exchange to a unidirectional closed-circuit water system in the bottom of the immersion tank coursing through a stream source. The level of the water may be adjusted to any desired level by means of a waste line or an inlet of tap water.

Equipment Design↗
PubMed1989

Pulmonary and ventilatory responses to pregnancy, immersion, and exercise.

To examine the effects of pregnancy, immersion, and exercise during immersion on pulmonary function and ventilation, 12 women were studied at 15, 25, and 35 wk of pregnancy and 8-10 wk postpartum. Pulmonary function and ventilation were measured under three experimental conditions: after 20 min of rest on land (LR), after 20 min of rest during immersion to the level of the xiphoid (IR), and after 20 min of exercise during immersion at 60% of predicted maximal capacity (IE). Forced vital capacity remained relatively constant, except for a decrease at 15 wk, for the duration of pregnancy. Expiratory reserve volume decreased with a change in the pregnancy status and with the duration of pregnancy. However, the forced vital capacity was maintained by an increase in the inspiratory capacity during pregnancy. Forced expiratory volume for 1 s, expressed as percent of forced vital capacity, did not differ significantly between conditions or as a result of pregnancy. Forced vital capacity was lower during the IR trial compared with LR and IE trials. The decreased forced vital capacity of the IR trials was mediated by a decrease in the expiratory reserve volume. Whereas the inspiratory capacity increased during IR and IE compared with LR, the increase was not large enough to offset the decrease in the expiratory reserve volume. Resting immersion resulted in a significant decrease in maximal voluntary ventilation as did pregnancy. Pregnancy resulted in significant increases in minute ventilation (VE), which were related to increases in the O2 consumption.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Thermoregulation during cold water immersion is unimpaired by low muscle glycogen levels.

This investigation studied the importance of muscle glycogen levels for body temperature regulation during cold stress. Physiological responses of eight euglycemic males were measured while they rested in cold (18 degrees C, stirred) water on two separate occasions. The trials followed a 3-day program of diet and exercise manipulation designed to produce either high (HMG) or low (LMG) preimmersion glycogen levels in the muscles of the legs, arms, and upper torso. Preimmersion vastus lateralis muscle glycogen concentrations were lower during the LMG trial (144 +/- 14 mmol glucose/kg dry tissue) than the HMG trial (543 +/- 53 mmol glucose/kg dry tissue). There were no significant differences between the two trials in shivering as reflected by aerobic metabolic rate or in the amount of body cooling as reflected by changes in rectal temperature during the immersions. Postimmersion muscle glycogen levels remained unchanged from preimmersion levels in both trials. Small but significant increases in plasma glucose and lactate concentration occurred during both immersions. Plasma glycerol increased during immersion in the LMG trial but not in the HMG trial. Plasma free fatty acid concentration increased during both immersion trials, but the change was apparent sooner in the LMG immersion. It was concluded that thermoregulatory responses of moderately lean and fatter individuals exposed to cold stress were not impaired by a substantial reduction in the muscle glycogen levels of several major skeletal muscle groups. Furthermore, the data suggest that, depending on the intensity of shivering, other metabolic substrates are available to enable muscle glycogen to be spared.

Adult↗