Design and Control Optimization of Microclimate Liquid Cooling Systems Underneath Protective Clothing

Flouris, Andreas D.; Cheung, Stephen S.

doi:10.1007/s10439-005-9061-9

Cited by 98 publications

(60 citation statements)

References 73 publications

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“…Initial data preparation included computing 1-min mean values from all the iDISK and Tm data recorded every 15 s. All subsequent analyses were conducted using these 1-min mean values. Measurements taken on the body surface demonstrate a response delay in relation to internal changes (12,15). This was confirmed in the present study since initial assessment of iDISK data revealed a response delay in relation to Tm during the rest, exercise, and postexercise periods.…”

Section: Data Preparationsupporting

confidence: 88%

Noninvasive assessment of muscle temperature during rest, exercise, and postexercise recovery in different environments

Flouris

Webb²,

Kenny

2015

Journal of Applied Physiology

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Flouris AD, Webb P, Kenny GP. Noninvasive assessment of muscle temperature during rest, exercise, and postexercise recovery in different environments. J Appl Physiol 118: 1310-1320, 2015. First published March 26, 2015 doi:10.1152/japplphysiol.00932.2014.-We introduced noninvasive and accurate techniques to estimate muscle temperature (Tm) of vastus lateralis (VL), triceps brachii (TB), and trapezius (TRAP) during rest, exercise, and postexercise recovery using the insulation disk (iDISK) technique. Thirty-six volunteers (24 men, 12 women; 73.0 Ϯ 12.2 kg; 1.75 Ϯ 0.07 m; 24.4 Ϯ 5.5 yr; 49.2 Ϯ 6.8 ml·kg Ϫ1 ·min Ϫ1 peak oxygen uptake) underwent periods of rest, cycling exercise at 40% of peak oxygen uptake, and postexercise recovery in three environments: Normal (24°C, 56% relative humidity), Hot-Humid (30°C, 60% relative humidity), and Hot-Dry (40°C, 24% relative humidity). Participants were randomly allocated into the "model" and the "validation" groups. Stepwise regression analysis generated models that accurately predicted Tm (predTm) of VL (R 2 ϭ 0.73-0.91), TB (R 2 ϭ 0.85-0.93), and TRAP (R 2 ϭ 0.84 -0.86) using iDISK and the difference between the current iDISK temperature and that recorded between 1 and 4 min before. Cross-validation analyses in the validation group demonstrated small differences (P Ͻ 0.05) of no physiological significance, small effect size of the differences, and strong associations (r ϭ 0.85-0.97; P Ͻ 0.001) between Tm and predTm. Moreover, narrow 95% limits of agreement and low percent coefficient of variation were observed between Tm and predTm. It is concluded that the developed noninvasive, practical, and inexpensive techniques provide accurate estimations of VL, TB, and TRAP Tm during rest, cycling exercise, and postexercise recovery. intramuscular; insulation disk; vastus lateralis; triceps brachii; trapezius DURING EXERCISE, LARGE AMOUNTS of heat are produced in the exercising muscles, leading to increased muscle temperature (Tm) (22). This occurs within the first few seconds of repeated muscle contraction, confirming that Tm is a robust indicator of muscle metabolism. In this light, the strong link between Tm and exercise performance is not surprising. Indeed, a number of studies have shown that Tm is the most important factor in determining the outcome of exercise performance, especially during short-term high-intensity exercise (36 -38, 41). In addition, a 2-5% variation (depending on the contraction type and velocity) in performance has been proposed as a consequence of a change in Tm by 1°C (41). Therefore, knowledge of Tm during work and exercise is crucial to attain performance enhancements. In addition, Tm data have both clinical [in terms of assessing and refining postexercise recovery interventions (39)] and physiological [in terms of improving the assessment of thermometrically derived mean body temperature (26)] value, representing a much-needed source of information in human physiology.At present, measurement of Tm is a time-consuming, invasive, and expensive techniq...

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Section: Data Preparationsupporting

confidence: 88%

Noninvasive assessment of muscle temperature during rest, exercise, and postexercise recovery in different environments

Flouris

Webb²,

Kenny

2015

Journal of Applied Physiology

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“…Typically these garments come in two designs based on heat exchange properties. Active heat exchange garments are cooled by circulating liquid throughout the garment through a tubing network (21,82). Passive heat exchange garments have ice or gel packs that are inserted into the garment to provide the cooling effect (75).…”

Section: Countermeasures To Improve Function In Ms Patients During Thmentioning

confidence: 99%

Thermoregulation in multiple sclerosis

Davis

Wilson

White

et al. 2010

Journal of Applied Physiology

147

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Davis SL, Wilson TE, White AT, Frohman EM. Thermoregulation in multiple sclerosis. J Appl Physiol 109: 1531-1537. First published July 29, 2010 doi:10.1152/japplphysiol.00460.2010.-Multiple sclerosis (MS) is a progressive neurological disorder that disrupts axonal myelin in the central nervous system. Demyelination produces alterations in saltatory conduction, slowed conduction velocity, and a predisposition to conduction block. An estimated 60 -80% of MS patients experience temporary worsening of clinical signs and neurological symptoms with heat exposure. Additionally, MS may produce impaired neural control of autonomic and endocrine functions. This review focuses on five main themes regarding the current understanding of thermoregulatory dysfunction in MS: 1) heat sensitivity; 2) central regulation of body temperature; 3) thermoregulatory effector responses; 4) heat-induced fatigue; and 5) countermeasures to improve or maintain function during thermal stress. Heat sensitivity in MS is related to the detrimental effects of increased temperature on action potential propagation in demyelinated axons, resulting in conduction slowing and/or block, which can be quantitatively characterized using precise measurements of ocular movements. MS lesions can also occur in areas of the brain responsible for the control and regulation of body temperature and thermoregulatory effector responses, resulting in impaired neural control of sudomotor pathways or neural-induced changes in eccrine sweat glands, as evidenced by observations of reduced sweating responses in MS patients. Fatigue during thermal stress is common in MS and results in decreased motor function and increased symptomatology likely due to impairments in central conduction. Although not comprehensive, some evidence exists concerning treatments (cooling, precooling, and pharmacological) for the MS patient to preserve function and decrease symptom worsening during heat stress. demyelination; core temperature; sweating; skin blood flow; fatigue MULTIPLE SCLEROSIS (MS) is a disabling progressive neurological disorder affecting ϳ400,000 individuals in the United States. The pathophysiology of MS results in a disruption or loss of axonal myelin in the central nervous system (CNS), leading to the formation of scar tissue (sclerosis). MS is thought to involve a number of autoimmune injury cascades that appear to be dependent on the interaction of complex epigenetic and environmental factors. Immune responses in individuals with MS are skewed toward a proinflammatory state, resulting in inflammation, demyelination, and ultimately loss of axons and disorganization of normal tissue architecture within the CNS (23). Demyelination is associated with corresponding changes in axonal physiology, including a loss of saltatory properties of electrical conduction, reduction in conduction velocity, and a predisposition to conduction block. These pathophysiological mechanisms underlie the myriad of symptoms (Table 1) in individuals with MS and are contingent on the neuroanatomic l...

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“…These materials absorb energy during the heating process as phase change takes place, but release their energy to the environment in the phase change range during a reverse cooling process [1][2][3]. Theoretically, PCM's ability to preserve energy is relatively simple.…”

Section: Pcm's Applicationmentioning

confidence: 99%

“…In this way, heat stress is prevented. PCMs in clothing allow the clothing to act as a mediator between the body and the environment, protecting people in hazardous conditions [1][2][3][4][5][6].…”

Section: Pcm's Applicationmentioning

confidence: 99%

Phase Change Materials’ Application in Clothing Design

Lin

2012

Trans. Mat. Res. Soc. Japan

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Heat (energy released) and cool (energy absorbed) are two types of PCMs that have been developed and adopted in clothing and textiles design. Many special function and smart textiles have adopted this concept such as: ski wear, diver dry suits, underwear, socks, hats, masks, gloves, shoes, firefighters' gear, bedding like sheets and pillowcases, and medical clothing. This paper discusses current PCM applications in clothing and explores future usage.

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Design and Control Optimization of Microclimate Liquid Cooling Systems Underneath Protective Clothing

Cited by 98 publications

References 73 publications

Noninvasive assessment of muscle temperature during rest, exercise, and postexercise recovery in different environments

Noninvasive assessment of muscle temperature during rest, exercise, and postexercise recovery in different environments

Thermoregulation in multiple sclerosis

Phase Change Materials’ Application in Clothing Design

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