scholarly journals Effects of passive heat stress and recovery on human cognitive function: An ERP study

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254769
Author(s):  
Hiroki Nakata ◽  
Ryusuke Kakigi ◽  
Manabu Shibasaki
Keyword(s):  
Heat Stress ◽  
Cognitive Function ◽  
Neural Activity ◽  
Task Difficulty ◽  
Peak Amplitude ◽  
Whole Body ◽  
Internal Temperature ◽  
P300 Component ◽  
Body Cooling ◽  
Whole Body Cooling

Using event-related potentials (ERPs), we investigated the effects of passive heat stress and recovery on the human cognitive function with Flanker tasks, involving congruent and incongruent stimuli. We hypothesized that modulation of the peak amplitude and latency of the P300 component in ERP waveforms would differ with task difficulty during passive heat stress and recovery. Subjects performed the Flanker tasks before (Pre), at the end of whole body heating (Heat: internal temperature increase of ~1.2°C from the pre-heat baseline), and after the internal temperature had returned to the pre-heat baseline (Recovery). The internal temperature was regulated by a tube-lined suit by perfusing 50°C water for heat stress and 25°C water for recovery immediately after the heat stress. Regardless of task difficulty, the reaction time (RT) was shortened during Heat rather than Pre and Recovery, and standard deviations of RT (i.e., response variability) were significantly smaller during Heat than Pre. However, the peak amplitudes of the P300 component in ERPs, which involved selective attention, expectancy, and memory updating, were significantly smaller during Heat than during Pre, suggesting the impairment of neural activity in cognitive function. Notably, the peak amplitudes of the P300 component were higher during Recovery than during Heat, indicating that the impaired neural activity had recovered after sufficient whole-body cooling. An indicator of the stimulus classification/evaluation time (peak latency of P300) and the RT were shortened during Heat stress, but such shortening was not noted after whole-body cooling. These results suggest that hyperthermia affects the human cognitive function, reflected by the peak amplitude and latency of the P300 component in ERPs during the Flanker tasks, but sufficient treatment such as whole-body cooling performed in this study can recover those functions.

scholarly journals Effects of face/head and whole body cooling during passive heat stress on human somatosensory processing

2017 ◽  
Vol 312 (6) ◽  
pp. R996-R1003 ◽  
Author(s):  
Hiroki Nakata ◽  
Mari Namba ◽  
Ryusuke Kakigi ◽  
Manabu Shibasaki
Keyword(s):  
Blood Flow ◽  
Heat Stress ◽  
Neural Activity ◽  
Whole Body ◽  
Somatosensory Processing ◽  
Esophageal Temperature ◽  
Passive Heating ◽  
Head Cooling ◽  
Body Cooling ◽  
Whole Body Cooling

We herein investigated the effects of face/head and whole body cooling during passive heat stress on human somatosensory processing recorded by somatosensory-evoked potentials (SEPs) at C4′ and Fz electrodes. Fourteen healthy subjects received a median nerve stimulation at the left wrist. SEPs were recorded at normothermic baseline (Rest), when esophageal temperature had increased by ~1.2°C (heat stress: HS) during passive heating, face/head cooling during passive heating (face/head cooling: FHC), and after HS (whole body cooling: WBC). The latencies and amplitudes of P14, N20, P25, N35, P45, and N60 at C4′ and P14, N18, P22, and N30 at Fz were evaluated. Latency indicated speed of the subcortical and cortical somatosensory processing, while amplitude reflected the strength of neural activity. Blood flow in the internal and common carotid arteries (ICA and CCA, respectively) and psychological comfort were recorded in each session. Increases in esophageal temperature due to HS significantly decreased the amplitude of N60, psychological comfort, and ICA blood flow in the HS session, and also shortened the latencies of SEPs (all, P < 0.05). While esophageal temperature remained elevated, FHC recovered the peak amplitude of N60, psychological comfort, and ICA blood flow toward preheat baseline levels as well as WBC. However, the latencies of SEPs did not recover in the FHC and WBC sessions. These results suggest that impaired neural activity in cortical somatosensory processing during passive HS was recovered by FHC, whereas conduction velocity in the ascending somatosensory input was accelerated by increases in body temperature.

A virtual rat for simulating environmental and exertional heat stress

2014 ◽  
Vol 117 (11) ◽  
pp. 1278-1286 ◽  
Author(s):  
Vineet Rakesh ◽  
Jonathan D. Stallings ◽  
Jaques Reifman
Keyword(s):  
Heat Stress ◽  
Management Strategies ◽  
Thermal Response ◽  
Mitigation Strategies ◽  
Whole Body ◽  
External Temperature ◽  
Body Cooling ◽  
Whole Body Cooling ◽  
Exertional Heat Stress

Severe cases of environmental or exertional heat stress can lead to varying degrees of organ dysfunction. To understand heat-injury progression and develop efficient management and mitigation strategies, it is critical to determine the thermal response in susceptible organs under different heat-stress conditions. To this end, we used our previously published virtual rat, which is capable of computing the spatiotemporal temperature distribution in the animal, and extended it to simulate various heat-stress scenarios, including 1) different environmental conditions, 2) exertional heat stress, 3) circadian rhythm effect on the thermal response, and 4) whole body cooling. Our predictions were consistent with published in vivo temperature measurements for all cases, validating our simulations. We observed a differential thermal response in the organs, with the liver experiencing the highest temperatures for all environmental and exertional heat-stress cases. For every 3°C rise in the external temperature from 40 to 46°C, core and organ temperatures increased by ∼0.8°C. Core temperatures increased by 2.6 and 4.1°C for increases in exercise intensity from rest to 75 and 100% of maximal O2 consumption, respectively. We also found differences as large as 0.8°C in organ temperatures for the same heat stress induced at different times during the day. Even after whole body cooling at a relatively low external temperature (1°C for 20 min), average organ temperatures were still elevated by 2.3 to 2.5°C compared with normothermia. These results can be used to optimize experimental protocol designs, reduce the amount of animal experimentation, and design and test improved heat-stress prevention and management strategies.

scholarly journals Distribution and Severity of Hypoxic-Ischemic Lesions on Brain MRI Following Therapeutic Cooling: Selective Head Versus Whole Body Cooling

2011 ◽  
Vol 70 ◽  
pp. 722-722
Author(s):  
S Sarkar ◽  
J R Bapuraj ◽  
S M Donn ◽  
I Bhagat ◽  
J D Barks
Keyword(s):  
Brain Mri ◽  
Whole Body ◽  
Body Cooling ◽  
Whole Body Cooling

The Cooling Power of Pigeon Wings

1991 ◽  
Vol 155 (1) ◽  
pp. 193-202 ◽  
Author(s):  
ALBERT CRAIG ◽  
JACQUES LAROCHELLE
Keyword(s):  
Body Temperature ◽  
Heat Production ◽  
Heat Dissipation ◽  
Experimental System ◽  
Whole Body ◽  
Cooling Power ◽  
Wind Speeds ◽  
Maximum Value ◽  
Body Cooling ◽  
Whole Body Cooling

The rate of heat loss through the stretched wings (Hwings) was studied in resting pigeons preheated to a body temperature (43.7°C) within the range of those recorded during flight. The experimental system was designed to allow the calculation of Hwings from the increase in whole-body cooling rates resulting from exposure of the wings to various wind speeds (0–50 km h−1) at 23°C. The maximum value of HWings was 3.8 W, less than twice the heat production of a resting pigeon. This indicates that the contribution of the wings to heat dissipation during flight may not be nearly as important as has been supposed. At low windspeeds (0–12.5 km h−1), HWings corresponded to about 40% of the resting rate of heat production, and this value is discussed in connection with the various wing postures observed in hyperthermic birds.

The effect of whole body cooling in asphyxiated neonates with resource limitation: Challenges and experience

2018 ◽  
Vol 7 (1) ◽  
pp. 7
Author(s):  
Rahul Sinha ◽  
K Venkatnarayan ◽  
Vandana Negi ◽  
Kirandeep Sodhi ◽  
BM John
Keyword(s):  
Resource Limitation ◽  
Whole Body ◽  
Body Cooling ◽  
Whole Body Cooling

scholarly journals An In Vivo Assessment of Regional Brain Temperature during Whole-Body Cooling for Neonatal Encephalopathy

2020 ◽  
Vol 220 ◽  
pp. 73-79.e3
Author(s):  
Tai-Wei Wu ◽  
Jessica L. Wisnowski ◽  
Robert F. Geisler ◽  
Aaron Reitman ◽  
Eugenia Ho ◽  
...  
Keyword(s):  
Brain Temperature ◽  
Whole Body ◽  
Neonatal Encephalopathy ◽  
Regional Brain ◽  
Body Cooling ◽  
Whole Body Cooling ◽  
In Vivo Assessment

Subcutaneous fat necrosis, a rare but serious side effect of hypoxic-ischemic encephalopathy and whole-body hypothermia

2019 ◽  
Vol 47 (9) ◽  
pp. 986-990 ◽  
Author(s):  
Mahdi Alsaleem ◽  
Lina Saadeh ◽  
Valerie Elberson ◽  
Vasantha H.S. Kumar
Keyword(s):  
Therapeutic Hypothermia ◽  
Subcutaneous Fat ◽  
Whole Body ◽  
Subcutaneous Fat Necrosis ◽  
P Values ◽  
Life Threatening ◽  
The Mean ◽  
Body Cooling ◽  
Whole Body Cooling ◽  
Ischemic Encephalopathy

Abstract Objective To describe the clinical characteristics and risk factors in infants with subcutaneous fat necrosis (SFN) following therapeutic hypothermia for hypoxic-ischemic encephalopathy (HIE). Methods A case-control study was performed by a retrospective chart review of infants with moderate or severe HIE admitted to a level IV regional perinatal center and who underwent whole-body cooling. Results A total of 14 (8.1%) of 171 infants with moderate or severe HIE who underwent whole-body cooling developed SFN during hospitalization. There were more females [71% (10/14)] and large-for-gestational age (LGA) infants [28% (4/14)] in the SFN group vs. 36% females (57/157) and 8% LGA infants (13/157) in the group without SFN (P-values of 0.009 and 0.015, respectively). The mean lowest platelet count was lower 108 ± 55 109/L vs. 146 ± 62 109/L and the mean highest calcium level was higher 11.3 ± 2.5 vs. 10.6 ± 0.8 mg/dL in infants with SFN vs. infants without SFN, respectively (P-values of 0.0078 and 0.006, respectively). Distribution of skin lesions followed distinctive patterns representing the areas with direct contact with the cooling blanket. One infant developed severe, life-threatening hypercalcemia that required aggressive management, including diuretics, corticosteroids and bisphosphonates. Conclusion Although SFN is a rare complication of therapeutic hypothermia, it can be a life-threatening condition if complicated by severe hypercalcemia. Infants who undergo therapeutic hypothermia for HIE need regular skin examinations to evaluate for SFN. If SFN is identified, monitoring of serum calcium levels to prevent life-threatening hypercalcemia is recommended.

scholarly journals The nitric oxide dependence of cutaneous microvascular function to independent and combined hypoxic cold exposure

2020 ◽  
Vol 129 (4) ◽  
pp. 947-956
Author(s):  
Josh T. Arnold ◽  
Alex B. Lloyd ◽  
Stephen J. Bailey ◽  
Tomomi Fujimoto ◽  
Ryoko Matsutake ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Nitrite Reduction ◽  
Whole Body ◽  
Local Cooling ◽  
Cutaneous Reflex ◽  
Body Cooling ◽  
Whole Body Cooling ◽  
Oxide Removal ◽  
Oxide Synthase

When separated from local cooling, whole body cooling elicited cutaneous reflex vasoconstriction via mechanisms independent of nitric oxide removal. Hypoxia elicited cutaneous vasodilatation via mechanisms mediated primarily by nitric oxide synthase, rather than xanthine oxidase-mediated nitrite reduction. Cold-induced vasoconstriction was blunted by the opposing effect of hypoxic vasodilatation, whereas the underpinning mechanisms did not interrelate in the absence of local cooling. Full vasoconstriction was restored with nitric oxide synthase inhibition.

Whole-Body Cryotherapy as a Tool to Improving of Infrared Thermography Diagnostics

2020 ◽  
pp. 265-296
Author(s):  
Armand Cholewka ◽  
Agata Stanek ◽  
Karolina Sieroń-Stołtny ◽  
Joanna Kajewska
Keyword(s):  
Low Temperature ◽  
Temperature Gradient ◽  
Infrared Thermography ◽  
Diagnostic Procedure ◽  
Whole Body ◽  
Therapeutic Technique ◽  
Body Cooling ◽  
Whole Body Cooling ◽  
Whole Body Cryotherapy ◽  
Physiological Reactions

The use of low temperature on the whole human body switched on beneficial physiological reactions. Whole-body cryotherapy is used as a part of rehabilitation. There were reported studies of thermal imaging performed due to whole body cooling in case of patients suffering from different diseases that showed a significant enhancement of the skin temperature gradient observed after cryotherapy. That explains that such therapeutic technique like whole-body cryotherapy can be used as a part of infrared thermography diagnostic procedure.

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