Wasser-Elektrolyt-Elimination und renale H�modynamik bei Erh�hung der Umgebungstemperatur

Kaufmann, Walter A.; Nieth, H; Schlitter, J. G.

doi:10.1007/bf00680939

“…During a 3 h exposure to a low humidity 46"-55"C environment in another study, renal blood flow fell 15% as internal temperature rose O.5"-1.l0C (1). When humans were exposed to a 40°C environment with greater than 50% relative humidity in two separate studies (122,131), renal blood flow fell 25%-30% due to renal vasoconstriction. In one of these studies (122), internal temperature increased by 1°C.…”

Section: Renal Circulationmentioning

confidence: 99%

“…When humans were exposed to a 40°C environment with greater than 50% relative humidity in two separate studies (122,131), renal blood flow fell 25%-30% due to renal vasoconstriction. In one of these studies (122), internal temperature increased by 1°C. In one subject heated by a waterperfused suit until internal temperature rose 1.8"C, renal blood flow fell 27% (219) (Fig.…”

Section: Renal Circulationmentioning

confidence: 99%

Cardiovascular Adjustments to Heat Stress

Johnson

¹

,

Proppe

²

1996

Comprehensive Physiology

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“…However, a paradoxical reduction in urine‐concentrating ability occurs in parallel to reductions in glomerular filtration rate (Wade & Claybaugh, 1980; Wade, Freund, & Claybaugh, 1989). Based on previous studies that used passive heat stress (Kaufmann et al., 1960; Kenney, 1952; Radigan & Robinson, 1949; Smith et al., 1952), we hypothesized that glomerular filtration rate would be reduced by acute heat stress, but this was not observed. Instead, glomerular filtration rate was maintained, and heat acclimation did not alter this response (Figure 1a).…”

Section: Discussionmentioning

confidence: 97%

“…Heat stress generally reduces renal blood flow (Chapman et al., 2019; Minson, Wladkowski, Cardell, Pawelczyk, & Kenney, 1998, 1999; Radigan & Robinson, 1949; Rowell, Brengelmann, Blackmon, & Murray, 1970, 1971) owing to increases in circulating vasopressin concentrations (Wade & Claybaugh, 1980) and increased sympathetic nerve activity (Gisolfi, Matthes, Kregel, & Oppliger, 1991; Vander, 1965; Yoshimoto, Sakagami, Nagura, & Miki, 2004). The reduction in renal blood flow during heat stress may reduce glomerular filtration rate (Kaufmann, Nieth, & Schlitter, 1960; Kenney, 1952; Radigan & Robinson, 1949; Smith, Robinson, & Pearcy, 1952), although this is not always observed, particularly during passive heat exposure (Melin et al., 2001; Traks & Sancetta, 1962). In addition, dehydration that typically accompanies heat stress results in increased aldosterone and vasopressin concentrations that act to stimulate fluid reabsorption, which may (von Ameln, Laniado, Rocker, & Kirsch, 1985) or may not (Melin et al., 2001) reduce urine production.…”

Section: Introductionmentioning

confidence: 99%

“…One limitation of previous studies that have evaluated kidney function during heat exposure, with or without heat acclimation, is that most studies used models of exercise in hot environments, making it difficult to isolate the effect of heat stress from that of exercise. Although a few studies have examined the renal response to passive heat stress (Chapman et al., 2019; Kaufmann et al., 1960; Kenney, 1952; Melin et al., 2001; Radigan & Robinson, 1949; Smith et al., 1952), no study has explored how passive heat acclimation might alter kidney function during subsequent heat exposure.…”

Section: Introductionmentioning

confidence: 99%

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Impact of passive heat acclimation on markers of kidney function during heat stress

Ravanelli

¹

,

Barry

²

,

Schlader

³

et al. 2020

Experimental Physiology

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Little is known about the effect of heat acclimation on kidney function during heat stress. The purpose of this study was to determine the impact of passive heat stress and subsequent passive heat acclimation on markers of kidney function. Twelve healthy adults (seven men and five women; 26 ± 5 years of age; 72.7 ± 8.6 kg; 172.4 ± 7.5 cm) underwent passive heat stress before and after a 7 day controlled hyperthermia heat acclimation protocol. The impact of passive heat exposure on urine and serum markers of kidney function was evaluated before and after heat acclimation. Glomerular filtration rate, determined from creatinine clearance, was unchanged with passive heat stress before (pre, 133 ± 41 ml min −1 ; post, 127 ± 51 ml min −1 ; P = 0.99) and after (pre, 129 ± 46 ml min −1 ; post, 130 ± 36 ml min −1 ; P = 0.99) heat acclimation. The urine-to-serum osmolality ratio was reduced after passive heating (P < 0.01), but heat acclimation did not alter this response. In comparison to baseline, free water clearance was greater after passive heating before (pre, −0.86 ± 0.67 ml min −1 ; post, 0.40 ± 1.01 ml min −1 ; P < 0.01) but not after (pre, −0.16 ± 0.57 ml min −1 ; post, 0.76 ± 1.2 ml min −1 ; P = 0.11) heat acclimation. Furthermore, passive heating increased the fractional excretion rate of potassium (P < 0.03) but not sodium (P = 0.13) or chloride (P = 0.20). Lastly, heat acclimation reduced the fractional incidence of albuminuria after passive heating (before, 58 ± 51%; after, 8 ± 29%; P = 0.03). Collectively, these results demonstrate that passive heat stress does not alter the glomerular filtration rate. However, heat acclimation might improve urineconcentrating ability and filtration within the glomerulus.

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Cardiovascular Adjustments to Thermal Stress

Rowell

¹

1983

Comprehensive Physiology

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The sections in this article are: Critique of Some Methods Employed in Humans Total and Regional Cutaneous Blood Flow Cardiac Output Central Blood Volume Regional Blood Flow Measurement of Temperature General Features of the Cutaneous Circulation: A Brief Review Cutaneous Blood Flow Cutaneous Blood Volume Innervation of Cutaneous Arterioles Local Control of Skin Blood Flow: Interaction With Reflexes Reflex and Local Control of Cutaneous Veins Circulatory Adjustments to Heat Stress in Resting Humans Changes in Cardiac Output, Blood Pressure, and Blood Volume Distribution of Cardiac Output in Heat‐Stressed Resting Humans Cardiac Output and Its Distribution in Heat‐Stressed Resting Subhuman Species Distribution of Blood Volume in Heat‐Stressed Resting Humans Mechanisms of Blood Flow Redistribution in Rest Acclimatization in Rest Interaction Between Thermoregulatory and Nonthermoregulatory Reflexes in Control of Skin Blood Flow Cutaneous Vascular Responses to Baroreflexes Cardiopulmonary (Low‐Pressure) Baroreflex Postural Influences: Hydrostatic Problem Upright Posture in Heat Stress: Interaction Between Reflex Vasoconstriction and Vasodilation Exercise Possible Modes of Reflex Interaction: Unsolved Problems Overall Circulatory Adjustments to Heat Stress and Exercise Distribution of Blood Volume Redistribution of Blood Flow During Exercise Central Circulation Adaptation to Heat Stress and Exercise: Acclimatization

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Wasser-Elektrolyt-Elimination und renale H�modynamik bei Erh�hung der Umgebungstemperatur

Cited by 3 publications

References 0 publications

Cardiovascular Adjustments to Heat Stress

Cardiovascular Adjustments to Heat Stress

Impact of passive heat acclimation on markers of kidney function during heat stress

Cardiovascular Adjustments to Thermal Stress

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