Effect of nifedipine on core cooling in rats during tail cold water immersion

Context Current treatment recommendations for American football players with exertional heatstroke are to remove clothing and equipment and immerse the body in cold water. It is unknown if wearing a full American football uniform during cold-water immersion (CWI) impairs rectal temperature (Trec) cooling or exacerbates hypothermic afterdrop. Objective To determine the time to cool Trec from 39.5°C to 38.0°C while participants wore a full American football uniform or control uniform during CWI and to determine the uniform's effect on Trec recovery postimmersion. Design Crossover study. Setting Laboratory. Patients or Other Participants A total of 18 hydrated, physically active, unacclimated men (age = 22 ± 3 years, height = 178.8 ± 6.8 cm, mass = 82.3 ± 12.6 kg, body fat = 13% ± 4%, body surface area = 2.0 ± 0.2 m2). Intervention(s) Participants wore the control uniform (undergarments, shorts, crew socks, tennis shoes) or full uniform (control plus T-shirt; tennis shoes; jersey; game pants; padding over knees, thighs, and tailbone; helmet; and shoulder pads). They exercised (temperature approximately 40°C, relative humidity approximately 35%) until Trec reached 39.5°C. They removed their T-shirts and shoes and were then immersed in water (approximately 10°C) while wearing each uniform configuration; time to cool Trec to 38.0°C (in minutes) was recorded. We measured Trec (°C) every 5 minutes for 30 minutes after immersion. Main Outcome Measure(s) Time to cool from 39.5°C to 38.0°C and Trec. Results The Trec cooled to 38.0°C in 6.19 ± 2.02 minutes in full uniform and 8.49 ± 4.78 minutes in control uniform (t17 = −2.1, P = .03; effect size = 0.48) corresponding to cooling rates of 0.28°C·min−1 ± 0.12°C·min−1 in full uniform and 0.23°C·min−1 ± 0.11°C·min−1 in control uniform (t17 = 1.6, P = .07, effect size = 0.44). The Trec postimmersion recovery did not differ between conditions over time (F1,17 = 0.6, P = .59). Conclusions We speculate that higher skin temperatures before CWI, less shivering, and greater conductive cooling explained the faster cooling in full uniform. Cooling rates were considered ideal when the full uniform was worn during CWI, and wearing the full uniform did not cause a greater postimmersion hypothermic afterdrop. Clinicians may immerse football athletes with hyperthermia wearing a full uniform without concern for negatively affecting body-core cooling.

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Effect of alcohol on thermal balance of man in cold water

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y79-131 ◽

1979 ◽

Vol 57 (8) ◽

pp. 860-865 ◽

Cited By ~ 21

Author(s):

G. R. Fox ◽

J. S. Hayward ◽

G. N. Hobson

Keyword(s):

Metabolic Rate ◽

Cold Water ◽

Water Immersion ◽

Cold Water Immersion ◽

Cooling Rates ◽

Rate Of Increase ◽

Exercise Period ◽

Hot Bath ◽

Core Cooling ◽

Skin Temperatures

The effects of alcohol on core cooling rates (rectal and tympanic), skin temperatures, and metabolic rate were determined for 10 subjects rendered hypothermic by immersion for 45 min in 10 °C water. Experiments were duplicated with and without a 20-min period of exercise at the beginning of cold water immersion. Measurements were continued during rewarming in a hot bath. With blood alcohol concentrations averaging 82 mg 100 mL−1, core cooling rates and changes in skin temperatures were insignificantly different from controls, even if the exercise period was imposed. Alcohol reduced shivering metabolic rate by an overall mean of 13%, insufficient to affect cooling rate. Alcohol had no effect on metabolic rate during exercise. During rewarming by hot bath, the amount of 'afterdrop' and rate of increase in core temperature were unaffected by alcohol. It was concluded that alcohol in a moderate dosage does not influence the rate of progress into hypothermia or subsequent, efficient rewarming. This emphasizes that the high incidence of alcohol involvement in water-related fatalities is due to alcohol potentiation of accidents rather than any direct effects on cold water survival, although very high doses of alcohol leading to unconsciousness would increase rate of progress into hypothermia.

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Core Temperature Responses to Cold-Water Immersion Recovery: A Pooled-Data Analysis

International Journal of Sports Physiology and Performance ◽

10.1123/ijspp.2017-0661 ◽

2018 ◽

Vol 13 (7) ◽

pp. 917-925 ◽

Cited By ~ 3

Author(s):

Jessica M. Stephens ◽

Ken Sharpe ◽

Christopher Gore ◽

Joanna Miller ◽

Gary J. Slater ◽

...

Keyword(s):

Core Temperature ◽

Time Course ◽

Cold Water ◽

Water Immersion ◽

Cold Water Immersion ◽

Careful Consideration ◽

Double Difference ◽

Pooled Data ◽

Core Cooling ◽

Temperature Responses

Purpose: To examine the effect of postexercise cold-water immersion (CWI) protocols, compared with control (CON), on the magnitude and time course of core temperature (Tc) responses. Methods: Pooled-data analyses were used to examine the Tc responses of 157 subjects from previous postexercise CWI trials in the authors’ laboratories. CWI protocols varied with different combinations of temperature, duration, immersion depth, and mode (continuous vs intermittent). Tc was examined as a double difference (ΔΔTc), calculated as the change in Tc in CWI condition minus the corresponding change in CON. The effect of CWI on ΔΔTc was assessed using separate linear mixed models across 2 time components (component 1, immersion; component 2, postintervention). Results: Intermittent CWI resulted in a mean decrease in ΔΔTc that was 0.25°C (0.10°C) (estimate [SE]) greater than continuous CWI during the immersion component (P = .02). There was a significant effect of CWI temperature during the immersion component (P = .05), where reductions in water temperature of 1°C resulted in decreases in ΔΔTc of 0.03°C (0.01°C). Similarly, the effect of CWI duration was significant during the immersion component (P = .01), where every 1 min of immersion resulted in a decrease in ΔΔTc of 0.02°C (0.01°C). The peak difference in Tc between the CWI and CON interventions during the postimmersion component occurred at 60 min postintervention. Conclusions: Variations in CWI mode, duration, and temperature may have a significant effect on the extent of change in Tc. Careful consideration should be given to determine the optimal amount of core cooling before deciding which combination of protocol factors to prescribe.

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Patient Involvement in Treatment Decision Making Can Help or Hinder Placebo Analgesia

Zeitschrift für Psychologie ◽

10.1027/2151-2604/a000179 ◽

2014 ◽

Vol 222 (3) ◽

pp. 165-170 ◽

Cited By ~ 2

Author(s):

Andrew L. Geers ◽

Jason P. Rose ◽

Stephanie L. Fowler ◽

Jill A. Brown

Keyword(s):

Patient Involvement ◽

Cold Water ◽

Prior Experience ◽

Water Immersion ◽

Treatment Decision ◽

Cold Water Immersion ◽

Not Given ◽

Placebo Analgesia ◽

Treatment Decision Making ◽

Immersion Experience

Experiments have found that choosing between placebo analgesics can reduce pain more than being assigned a placebo analgesic. Because earlier research has shown prior experience moderates choice effects in other contexts, we tested whether prior experience with a pain stimulus moderates this placebo-choice association. Before a cold water pain task, participants were either told that an inert cream would reduce their pain or they were not told this information. Additionally, participants chose between one of two inert creams for the task or they were not given choice. Importantly, we also measured prior experience with cold water immersion. Individuals with prior cold water immersion experience tended to display greater placebo analgesia when given choice, whereas participants without this experience tended to display greater placebo analgesia without choice. Prior stimulus experience appears to moderate the effect of choice on placebo analgesia.

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Thermoregulatory responses to cold water at different times of day

Journal of Applied Physiology ◽

10.1152/jappl.1999.87.1.243 ◽

1999 ◽

Vol 87 (1) ◽

pp. 243-246 ◽

Cited By ~ 7

Author(s):

John W. Castellani ◽

Andrew J. Young ◽

James E. Kain ◽

Michael N. Sawka

Keyword(s):

Cold Water ◽

Water Immersion ◽

Early Morning ◽

Cold Water Immersion ◽

Time Of Day ◽

Mean Skin Temperature ◽

Mean Body Temperature ◽

Metabolic Heat ◽

Body Temperature Change ◽

The Mean

This study examined how time of day affects thermoregulation during cold-water immersion (CWI). It was hypothesized that the shivering and vasoconstrictor responses to CWI would differ at 0700 vs. 1500 because of lower initial core temperatures (Tcore) at 0700. Nine men were immersed (20°C, 2 h) at 0700 and 1500 on 2 days. No differences ( P > 0.05) between times were observed for metabolic heat production (M˙, 150 W ⋅ m−2), heat flow (250 W ⋅ m−2), mean skin temperature (T sk, 21°C), and the mean body temperature-change in M˙(ΔM˙) relationship. Rectal temperature (Tre) was higher ( P < 0.05) before (Δ = 0.4°C) and throughout CWI during 1500. The change in Tre was greater ( P < 0.05) at 1500 (−1.4°C) vs. 0700 (−1.2°C), likely because of the higher Tre-T skgradient (0.3°C) at 1500. These data indicate that shivering and vasoconstriction are not affected by time of day. These observations raise the possibility that CWI may increase the risk of hypothermia in the early morning because of a lower initial Tcore.

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Changes in myocardial myosin heavy chain isoform composition with exercise and post-exercise cold-water immersion

Journal of Muscle Research and Cell Motility ◽

10.1007/s10974-021-09603-z ◽

2021 ◽

Author(s):

Ramzi A. Al-horani ◽

Mukhallad A. Mohammad ◽

Saja Haifawi ◽

Mohammed Ihsan

Keyword(s):

Myosin Heavy Chain ◽

Heavy Chain ◽

Cold Water ◽

Water Immersion ◽

Cold Water Immersion ◽

Post Exercise ◽

Myosin Heavy Chain Isoform

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Recovery strategies implemented by sport support staff of elite rugby players in South Africa

South African Journal of Physiotherapy ◽

10.4102/sajp.v65i1.78 ◽

2009 ◽

Vol 65 (1) ◽

Cited By ~ 6

Author(s):

D.V. Van Wyk ◽

M.I. Lambert

Keyword(s):

Cold Water ◽

Water Immersion ◽

Total Duration ◽

Cold Water Immersion ◽

Support Staff ◽

Medical Support ◽

Cross Sectional ◽

Study Results ◽

Recovery Strategies ◽

Rugby Players

Objective: The main aim of this study was to determine strategies used toaccelerate recovery of elite rugby players after training and matches, asused by medical support staff of rugby teams in South A frica. A secondaryaim was to focus on specifics of implementing ice/cold water immersion asrecovery strategy. Design: A Questionnaire-based cross sectional descriptive survey was used.Setting and Participants: Most (n=58) of the medical support staff ofrugby teams (doctors, physiotherapists, biokineticists and fitness trainers)who attended the inaugural Rugby Medical A ssociation conference linked to the South A frican Sports MedicineA ssociation Conference in Pretoria (14-16th November, 2007) participated in the study. Results: Recovery strategies were utilized mostly after matches. Stretching and ice/cold water immersion were utilized the most (83%). More biokineticists and fitness trainers advocated the usage of stretching than their counter-parts (medical doctors and physiotherapists). Ice/Cold water immersion and A ctive Recovery were the top two ratedstrategies. A summary of the details around implementation of ice/cold water therapy is shown (mean) as utilized bythe subjects: (i) The time to immersion after matches was 12±9 min; (ii) The total duration of one immersion sessionwas 6±6 min; (iii) 3 immersion sessions per average training week was utilized by subjects; (iv) The average water temperature was 10±3 ºC.; (v) Ice cubes were used most frequently to cool water for immersion sessions, and(vi) plastic drums were mostly used as the container for water. Conclusion: In this survey the representative group of support staff provided insight to which strategies are utilizedin South A frican elite rugby teams to accelerate recovery of players after training and/or matches.

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Cold-water immersion following sprint interval training does not alter endurance signaling pathways or training adaptations in human skeletal muscle

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00434.2016 ◽

2017 ◽

Vol 313 (4) ◽

pp. R372-R384 ◽

Cited By ~ 13

Author(s):

James R. Broatch ◽

Aaron Petersen ◽

David J. Bishop

Keyword(s):

Mitochondrial Biogenesis ◽

Molecular Mechanisms ◽

Cold Water ◽

P53 Protein ◽

Water Immersion ◽

Interval Training ◽

Cold Water Immersion ◽

Peroxisome Proliferator ◽

Sprint Interval Training ◽

Single Session

We investigated the underlying molecular mechanisms by which postexercise cold-water immersion (CWI) may alter key markers of mitochondrial biogenesis following both a single session and 6 wk of sprint interval training (SIT). Nineteen men performed a single SIT session, followed by one of two 15-min recovery conditions: cold-water immersion (10°C) or a passive room temperature control (23°C). Sixteen of these participants also completed 6 wk of SIT, each session followed immediately by their designated recovery condition. Four muscle biopsies were obtained in total, three during the single SIT session (preexercise, postrecovery, and 3 h postrecovery) and one 48 h after the last SIT session. After a single SIT session, phosphorylated (p-)AMPK, p-p38 MAPK, p-p53, and peroxisome proliferator-activated receptor-γ coactivator-1α ( PGC-1α) mRNA were all increased ( P < 0.05). Postexercise CWI had no effect on these responses. Consistent with the lack of a response after a single session, regular postexercise CWI had no effect on PGC-1α or p53 protein content. Six weeks of SIT increased peak aerobic power, maximal oxygen consumption, maximal uncoupled respiration (complexes I and II), and 2-km time trial performance ( P < 0.05). However, regular CWI had no effect on changes in these markers, consistent with the lack of response in the markers of mitochondrial biogenesis. Although these observations suggest that CWI is not detrimental to endurance adaptations following 6 wk of SIT, they question whether postexercise CWI is an effective strategy to promote mitochondrial biogenesis and improvements in endurance performance.

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