ArticlePDF Available

The roles of hands and feet in temperature regulation in hot and cold environments



In this paper, we briefly review the physiological and biophysical characteristics of the hands and feet, and their association with autonomic (physiological) and behavioural temperature regulation, and with thermal injury. A comprehensive review of this topic is not currently available within the literature. The temperatures of the skin and subcutaneous tissues, particularly those of the hands and feet, vary significantly as air temperatures move away from the thermal comfort zone. Mean skin temperature increases approximately 0.7oC for each 1oC elevation in air temperature, with smaller changes at the hands (0.46o.oC-1) and slightly larger changes at the feet (0.8o.oC-1: Bedford, 1936). These variations reflect local differences in metabolic rate, convective heat delivery (mass flow) and thermal exchanges with the thermal environment.
University of Wollongong
Research Online
Faculty of Health and Behavioural Sciences - Papers Faculty of Health and Behavioural Sciences
e roles of hands and feet in temperature
regulation in hot and cold environments
Nigel A.S. Taylor
University of Wollongong,
Christiano Machado-Moreira
University of Wollongong,
Anne van den Heuvel
University of Wollongong,
Joanne Caldwell
University of Wollongong,
Elizabeth A. Taylor
University of Wollongong
See next page for additional authors
Research Online is the open access institutional repository for the
University of Wollongong. For further information contact Manager
Repository Services:
Publication Details
Taylor, N. A.S.., Machado-Moreira, C., van den Heuvel, A., Caldwell, J., Taylor, E. A.. & Tipton, M. J.. e roles of hands and feet in
temperature regulation in hot and cold environments. irteenth International Conference on Environmental Ergonomics; Boston,
USA: University of Wollongong; 2009. 405-409.
e roles of hands and feet in temperature regulation in hot and cold
In this paper, we briey review the physiological and biophysical characteristics of the hands and feet, and
their association with autonomic (physiological) and behavioural temperature regulation, and with thermal
injury. A comprehensive review of this topic is not currently available within the literature. e temperatures
of the skin and subcutaneous tissues, particularly those of the hands and feet, vary signicantly as air
temperatures move away from the thermal comfort zone. Mean skin temperature increases approximately
0.7oC for each 1oC elevation in air temperature, with smaller changes at the hands (0.46o.oC-1) and slightly
larger changes at the feet (0.8o.oC-1: Bedford, 1936). ese variations reect local dierences in metabolic
rate, convective heat delivery (mass ow) and thermal exchanges with the thermal environment.
hot, hands, cold, environments, feet, temperature, regulation, roles
Publication Details
Taylor, N. A.S.., Machado-Moreira, C., van den Heuvel, A., Caldwell, J., Taylor, E. A.. & Tipton, M. J.. e roles
of hands and feet in temperature regulation in hot and cold environments. irteenth International
Conference on Environmental Ergonomics; Boston, USA: University of Wollongong; 2009. 405-409.
Nigel A.S. Taylor, Christiano Machado-Moreira, Anne van den Heuvel, Joanne Caldwell, Elizabeth A. Taylor,
and Michael J. Tipton
is conference paper is available at Research Online: hp://
Proceedings of the 13th International Conference on Environmental Ergonomics, Boston (USA), August 2-7, 2009
Nigel A.S. Taylor1, Christiano A. Machado-Moreira1, Anne M.J. van den Heuvel1,
Joanne N. Caldwell1, Elizabeth A. Taylor1 and Michael J. Tipton2
1Thermal Physiology Laboratory, University of Wollongong, Wollongong, Australia
2Human and Applied Physiology Laboratory, University of Portsmouth, Portsmouth, England
Contact person:
In this paper, we briefly review the physiological and biophysical characteristics of the hands
and feet, and their association with autonomic (physiological) and behavioural temperature
regulation, and with thermal injury. A comprehensive review of this topic is not currently
available within the literature.
The temperatures of the skin and subcutaneous tissues, particularly those of the hands and feet,
vary significantly as air temperatures move away from the thermal comfort zone. Mean skin
temperature increases approximately 0.7oC for each 1oC elevation in air temperature, with
smaller changes at the hands (0.46o.oC-1) and slightly larger changes at the feet (0.8o.oC-1:
Bedford, 1936). These variations reflect local differences in metabolic rate, convective heat
delivery (mass flow) and thermal exchanges with the thermal environment.
Thermoregulation is achieved by modulating physiological efferent functions (skin blood flow,
sweating, shivering) and implementing behavioural strategies, following the central integration
of thermal feedback from the deep body and superficial tissues. In all environments, cutaneous
thermoreceptors provide the first thermal feedback signals, giving rise to thermal sensations,
physiological adjustments and eventually to decisions relating to the pleasantness or comfort that
the environment and associated responses evoke.
The principal nerves carrying thermoreceptor feedback from the hand are the radial and median
nerves, with the latter having a more important sensory role. This feedback travels to the spinal
cord via the 6th, 7th and 8th cervical spinal nerves, and eventually to the hypothalamus. For the
foot, the corresponding nerves are the tibial, sural and superficial fibular nerves, which enter the
spinal cord via the 1st sacral and 5th lumbar spinal nerves: these nerves also relay efferent signals
that control blood flow, sweating and muscular function. The nerves that dictate thermoeffector
function of the hand leave the spinal cord at the thoracic segments (T2-T8), while those for the
foot leave at the thoracic and lumbar segments (T11-L2).
Most neurones of the sympathetic nervous system are noradrenergic. However, this does not
hold for the thermoefferent fibres, which possess at least three different neurotransmitters. For
instance, the fibres that innervate most eccrine sweat glands are cholinergic, with perhaps some
evidence of noradrenergic control at the glabrous (hairless) surfaces of the hands and feet. Skin
blood flow to these glabrous surfaces is determined solely by noradrenergically mediated
vasoconstrictor nerves (Kellogg, 2006). In contrast, blood flow to the non-glabrous (hairy) skin
regions is mediated by separate noradrenergic vasoconstrictor and active vasodilatory branches
Proceedings of the 13th International Conference on Environmental Ergonomics, Boston (USA), August 2-7, 2009
of the sympathetic nervous system; the neurotransmitter for the latter pathway awaits
identification (Kellogg, 2006).
Blood flow to the hands is provided through the radial and ulnar arteries, and via the deep palmar
arch, the superficial palmar branch, the metacarpal arteries and the digital arteries. In the foot,
blood enters from behind each of the malleoli (malleolar arteries) and across the upper surface of
the foot (dorsalis pedis artery). The positioning of these vessels with respect to the bones of the
foot has significant implications for shoe design. Cutaneous capillaries are located just below the
epidermis, with hand veins draining into either superficial or deep vessels, the largest of which
run along the dorsal hand and foot surfaces. Hands and feet also contain arteriovenous
anastomoses, and when these shunts are open, dramatic elevations in skin blood flow can occur.
Indeed, these vessels are responsible for the extremities behaving as very efficient heat
exchangers (radiators), with thermal homeostasis sometimes being achieved entirely through
subtle changes in skin blood flow through the anastomoses of the hands, face and feet (Hales,
Under thermoneutral conditions, hand blood flow (10 mL.100 mL-1.min-1; Roddie, 1983) is
typically 3-4 times greater than that of the foot (3 mL.100 mL-1.min-1; Colemont and Decoutere,
1981). When normalised to the skin surface area, hand blood flow is 4-5 times greater than the
rest of the body, and about twice that of the foot (Taylor et al., 2008a). During protracted cold
exposures, extremely low local blood flows are observed (hand: 0.15 mL.100 mL-1.min-1; foot:
0.2 mL.100 mL-1.min-1; Taylor et al., 2008a, b), and such flows can be below the metabolic
requirements of these tissues. In the heat, maximal hand blood flow approximates 30 mL.100
mL-1.min-1, while 18 mL.100 mL-1.min-1 appears maximal for the foot (Taylor et al., 2008a, b).
Finger blood flows have greater minimal (0.2 mL.100 mL-1.min-1) to maximal variations (120
mL.100 mL-1.min-1) with changes in whole-body thermal state (Nagasaka et al., 1987). In
addition, blood flow at the middle phalanx is only about 30% of that at the distal phalanx
(Wilkins et al., 1938).
The single most important determinant of hand and foot blood flow is the thermal status of the
body core (Ferris et al., 1947), with a 1oC change in mean skin temperature producing a 1.3 fold
change (10 mL.100 mL-1.min-1) in finger blood flow, and the corresponding change in core
temperature resulting in a 2.8-fold change (32 mL.100 mL-1.min-1; Wenger et al., 1975). Thus,
local temperatures can influence blood flow, but this affect is minimal when the body core is
either hot or cold, and it is greatest when deep body temperature is within the thermoneutral
The blood supply to the hands and feet represents their primary source of heat, and the minimal
blood flows seen with deep and superficial tissue cooling, as a result of intense peripheral
vasoconstriction, represent a physiological amputation of these appendages. The consequence of
this is a loss of both sensation and function, and in particular manual dexterity. Insufficient tissue
perfusion and heat loss affect vascular smooth muscle contractility, which can, if core
temperature is normal or raised, result in vasodilatation. This cold-induced vasodilatation can
protect tissues from, and delay tissue damage. In the absence of tissue warming, extreme or
prolonged cooling of the extremities can result in non-freezing and freezing cold injury. The
Proceedings of the 13th International Conference on Environmental Ergonomics, Boston (USA), August 2-7, 2009
former condition has recently been associated with a cold-induced defect in vascular smooth
muscle contractility caused by a loss of NO-dependent endothelial function (Stephens et al.,
Relative to the entire body, the surface area to mass ratio for the hand is 4-5 larger, while that for
a foot is 2.5-3 larger (males-females). Therefore, these appendages provide an effective route for
heat exchange with the environment, as long as thermal energy can be delivered from the body
core via convective (mass flow) pathways.
The maximal hand and foot blood flows (30 and 18 mL.100 mL-1.min-1) can result in theoretical
peak heat transfers from the core to both hands of 12 W or 286 W.m-2 for a 1oC core-skin
gradient. The corresponding values for both feet are 16 W or 404 W.m-2. Thus, while the
absolute heat transfer to the hands and feet from the body core is not high, their surface-area
normalised transfer, when considered in combination with the huge capacity of the arteriovenous
anastomoses to elevate local skin blood flow, makes these appendages very important locations
for heat dissipation (Taylor et al., 2008a; 2008b).
This heat delivery, and its subsequent dissipation, is advantageous in the heat, as it facilitates
central cooling, but, as described above, it can be dangerous in the cold. Furthermore, these data
also represent maximal core-periphery transfers, and not that which occurs between the skin and
its surrounding environment. By using foot and hand temperatures observed during actual air
exposures to 15o, 27o and 45oC (Webb, 1992), the theoretical radiative and convective heat
transfers from each hand and foot to the surrounding air may be computed, and these represent
respective losses of 16.6 W and 25.5 W (15oC), and 7.7 W and 11.8 W (27oC), or gains of 18.1
W and 27.7 W (45oC). More impressive heat transfer occurs when the vasodilated appendages of
heated individuals are placed into cold water (Tipton et al., 1993). In this circumstance, heat loss
can range from 70-85 W (hands) and 90-95 W (feet: House and Tipton, 2002).
Sweat glands are widely distributed over the body surface, with a total of two-four million glands
capable of producing sweat at peak rates of 10-15 L.d-1. Each hand has approximately 160,000
eccrine sweat glands, with greater numbers on the palmar (115,000) than dorsal surface (46,000:
Machado-Moreira et al., 2008). Similarly, one foot has approximately 155,000 glands, with more
on the plantar (100,000) than the dorsal surface (55,000; Taylor et al., 2006).
Both the hands and feet display two general sweat patterns during heating: low secretion at the
glabrous surfaces, and moderate secretion from all other surfaces. During passive heating at rest
(40 min), where the average whole-body skin temperature was increased from 34.5oC to 35.9oC,
and core temperature was elevated to 37.2oC from 36.9oC, the palms and soles displayed the
lowest intra-segmental sweat rates (palm: 0.16; sole: 0.23
Conversely, the dorsal surfaces of the distal phalanges of the fingers (0.62 and
the distal phalanx of the big toe (0.50 displayed the highest sweat rates. Under
these experimental conditions, sweating averaged 0.38 from the hands (Machado-
Moreira et al., 2008) and 0.45 from the feet (Taylor et al., 2006).
Proceedings of the 13th International Conference on Environmental Ergonomics, Boston (USA), August 2-7, 2009
When exercising in the heat, sweat gland recruitment occurs almost simultaneously across most
body surfaces, including the hands and feet, although the intra-segmental distribution is not
uniform. The dorsal surfaces of both appendages display a relatively consistent secretion rate,
accounting for approximately 65-70% of total sweat flow from each extremity. Peak hand sweat
rates during heavy exercise are: 4.0 mL.h-1 (palm); 16.8 mL.h-1 (volar fingers); 16.6 mL.h-1
(dorsal fingers); and 15.0 mL.h-1 (dorsal hand: Machado-Moreira et al., 2008). Corresponding
sweat production from the foot is: 14.5 mL.h-1 (dorsal), 5.4 mL.h-1 (medial) 5.0 mL.h-1 (lateral),
16.0 mL.h-1 (plantar), 2.9 mL.h-1 (dorsal toes), and 1.1 mL.h-1 (plantar toes; Taylor et al., 2006).
Therefore, the maximal theoretical evaporative cooling possible from a single hand is about 35.4
W (assuming 100% evaporation), and 27.6 W from one foot. Indeed, when normalised to surface
area, the potential for evaporative heat loss from the two hands is 110% greater than at the torso,
and 200% greater than at both feet, but only half that of the forehead (Taylor et al., 2008b).
Thermal sensations arise within the somatosensory cortex. Sensory feedback from the face and
hands, and to a lesser extent the feet and toes, is very powerful as these areas provide feedback to
a larger volume of the somatosensory cortex (Penfield and Rasmussen, 1952). Discomfort drives
behaviour, based upon the pleasantness of a given thermal state, and while this sensation is
related to both the core and peripheral temperatures, it is believed that thermal comfort is
primarily determined by the thermal state of the core (Hensel, 1981). It is known that a
separation exists between local and whole-body discomfort, such that one can have
uncomfortable feet while the rest of body remains thermally comfortable. However, the face,
hands and feet are associated with significantly greater thermal discomfort with local tissue
temperature changes. Indeed, the hands and feet provide very powerful feedback relative to local
comfort, but play a minimal role relative to whole-body thermal discomfort (Cotter et al., 1996).
These high local sensitivities are important to clothing design, but are of less importance to
behavioural responses. The head, however, dominates whole-body thermal sensation and
discomfort (Cotter and Taylor, 2005), so the thermal status of the face has a more powerful role
in dictating thermoregulatory behaviour.
Bedford, T. (1936). The warmth factor in comfort at work: a physiological study of heating and ventilation. In:
McIntyre, D.A. Indoor climate. Industrial Health Research Boards 76. HMSO London, Applied Science,
London. Pp. 1-102.
Colemont, L., and Decoutere, P. (1981). The in vivo determination of the blood volume in the foot using a mercury
strain gauge plethysmograph and I-131 labelled serum albumin. Cardiovasc. Res. 15:262-267.
Cotter, J.D., Zeyl, A., Kieser E., and Taylor, N.A.S. (1996). The role of local skin temperature in determining the
perception of local and whole-body thermal state. In: Shapiro, Y., Moran, D.S., and Epstein, Y. (Editors).
Environmental ergonomics: recent progress and new frontiers. Freund Publishing House. London, United
Kingdom. Pp. 85-88.
Cotter, J.D., and Taylor, N.A.S. (2005). Distribution of cutaneous sudomotor and alliesthesial thermosensitivity in
mildly heat-stressed humans: an open-loop approach. J. Physiol. 565:335-345.
Ferris, B.G., Forster, R.E., Pillion, E.L., and Christensen, W.R. (1947). Control of peripheral blood flow: responses
in the human hand when extremities are warmed. Am. J. Physiol. 150:304-314.
Hales, J.R.S. (1985). Skin arteriovenous anastomoses, their control and role in thermoregulation. In: Johansen, K.,
and Burggren, W.W. Cardiovascular shunts. Alfred Benzon Symposium. Pp. 433-448.
Hensel, H. (1981). Thermoreception and temperature regulation. Monographs of the Physiological Society, No. 38.
Academic Press, London.
Proceedings of the 13th International Conference on Environmental Ergonomics, Boston (USA), August 2-7, 2009
House, J.R., and Tipton, M.J. (2002). Heat strain is reduced at different rates with hand, foot, forearm and lower leg
cooling. In: Tochihara, Y. (Editor). Environmental Ergonomics X. Fukuoka, Japan. Pp. 85-88.
Kellogg, D.L. (2006). In vivo mechanisms of cutaneous vasodilation and vasoconstriction in humans during
thermoregulatory challenges. J. Appl. Physiol. 100:1709-1718.
Machado-Moreira, C.A., Caldwell, J.N., Mekjavic, I.B., and Taylor, N.A.S. (2008). Sweat secretion from palmar
and dorsal surfaces of the hands during passive and active heating. Aviat. Space Environ. Med. 79:1034-
Nagasaka, T., Cabanac, M., Hirata, K., and Nunomura, T. (1987). Control of local heat gain by vasomotor response
of the hand. J. Appl. Physiol. 63:1335-1338.
Penfield, W., and Rasmussen, T. (1952). The cerebral cortex of man. MacMillan Press, New York.
Roddie, I.C. (1983). Circulation to skin and adipose tissue. In: Shepherd, J.T., and Abboud, F.M. (Eds). The
cardiovascular system. Volume III. Peripheral circulation and organ blood flow Part 1. Handbook of
Physiology. American Physiological Society. Bethesda. Pp. 285-317.
Stephens, J. P., Laight, F., Golden, F., St.C., and Tipton, M. J. (2009). Damage to vascular endothelium and smooth
muscle contribute to the development of non-freezing cold injury in the rat tail vascular bed in vitro.
Proceedings of the Thirteenth International Conference on Environmental Ergonomics. August 2-7th,
Boston, U.S.A.
Taylor, N.A.S., Caldwell, J.N., and Mekjavic, I.B. (2006). The sweating foot: local differences in sweat secretion
during exercise-induced hyperthermia. Aviat. Space Environ. Med. 77:1020-1027.
Taylor, N.A.S., Machado-Moreira, C.A., van den Heuvel, A.M.J., Caldwell, J.N., Haley, C.D., and Kerry, P. (2008a).
The hand: physiological characteristics that impact upon temperature regulation and thermal comfort.
UOW-HPL-Report-032. Human Performance Laboratories, University of Wollongong. For: W.L. Gore &
Associates GmbH, Germany. Pp. 1-155.
Taylor, N.A.S., Machado-Moreira, C.A., van den Heuvel, A.M.J., Caldwell, J.N., Haley, C.D., and Kerry, P.
(2008b). Physiological characteristics of the foot with special relevance to thermoregulation and thermal
comfort. UOW-HPL-Report-031. Human Performance Laboratories, University of Wollongong. For: W.L.
Gore & Associates GmbH, Germany. Pp. 1-153.
Tipton, M.J., Allsopp, A., Balmi, P.J., and House, J.R. (1993). Hand immersion as a method of cooling and
rewarming: a short review. J. Roy. Nav. Med. Serv. 79:125-131.
Wenger, C.B., Roberts, M.F., Nadel, E.R., and Stolwijk, J.A.J. (1975). Thermoregulatory control of finger blood
flow. J. Appl. Physiol. 38:1078-1082.
Wilkins, R.W., Doupe, J., and Newman, H.W. (1938). The rate of blood flow in normal fingers. Clin. Sci. 3:403-411.
Some of the research reported within this review was supported by grants from W.L. Gore &
Associates GmbH (Germany) and from the Ministry of Defence (Republic of Slovenia).
... The study in this section investigates whether an objective derived from a working principle may be modeled parametrically for design optimization purposes by the engineering theory that guides that working principle. In this case a study was done previously to estimate empirically that 16 Watts of heat is transferred by human circulation to warm a foot and a maximum of 27.6 Watts can support evaporative cooling of a foot [14]. This is shown in the overall boot system representation on the left of Fig. 5 and Fig. 6, respectively. ...
Conference Paper
The design of products related to space life systems usually involves consideration of several main requirements or objectives sometimes with multidisciplinary facets. Examples of such a diverse set of requirements includes comfort, facilitating human performance, maintaining an oxygen environment, resistance to extreme temperatures, strength, long life, durability, ease of use, manufacturability, low maintenance, and low cost. This suggests a need for a design process that can dynamically model, analyze, and simulate all considerations holistically in a single formulation. This has been a difficult challenge because designs may be done by domain experts in a single area focused on optimization of a limited set of requirements in each design iteration. Ideally, a change during modeling to any design variable or parameter should inform about the effects on all objectives to include modeling of relative preferences between the objectives. This work introduces a Multi-Objective Parametric Optimization of System (MO-POS) framework to convert such a diverse set of system requirements into a single formulation for optimal system design. This MO-POS approach was deployed in the conceptual design of a space suit boot for surface missions. That deployment is presented in this paper to illustrate the potential benefits and salient features of this MO-POS approach for space life systems development.
... The fact that the fingers are the coolest part of a hand is not only related to thermal diffusion. Our organism has priorities in maintaining adequate temperature of various body parts: the energy is first used to heat important internal organs such as brain, heart or liver, and the extremities are heated in the second order [17]. Also, incorrect segmentation was observed more frequently for female hands than these of males, possibly relating to the menstrual cycle. ...
Conference Paper
Full-text available
This paper proposes a biometric recognition method based on thermal images of inner part of the hand, and a database of 21,000 thermal images of both hands acquired by a specialized thermal camera from 70 subjects. The data for each subject was acquired in three different sessions, with two first sessions organized on the same day, and the third session organized approximately two weeks apart. This allowed to analyze the stability of hand temperature in both short-term and long-term horizons. No hand stabilization or positioning devices were used during acquisition, making this setup closer to real-world, unconstrained applications. This required making our method translation-, rotation- and scale-invariant. Two approaches for feature selection and classification are proposed and compared: feature engineering deploying texture descriptors such as Binarized Statistical Image Features (BSIF) and Gabor wavelets, and feature learning based on convolutional neural networks (CNN) trained in different environmental conditions. For within-session scenario we achieved 0.36% and 0.00% of equal error rate (EER) in the first and the second approach, respectively. Between-session EER stands at 27.98% for the first approach and 17.17% for the second one. These results allow for estimation of a short-term stability of hand thermal information. This paper presents the first known to us database of hand thermal images and the first biometric system based solely on hand thermal maps acquired by thermal sensor in unconstrained scenario.
... The climatic temperature of some regions around the world varies between 5 °C and 45 °C. Taylor et al. [4], as well as Bedford [5], reported that there is a positive relationship between mean hand skin temperature and the environmental air temperature which influences the body's thermal exchanges with the thermal environment. ...
Full-text available
Daily working activities and functions require a high contribution of hand and forearm muscles in executing grip force. To study the effects of wearing different gloves on grip strength, under a variety of hand skin temperatures, an assessment of the maximum grip strength was performed with 32 healthy male workers with a mean age (standard deviation) of 30.44 (5.35) years wearing five industrial gloves at three hand skin temperatures. Their ages and anthropometric characteristics including body mass index (BMI), hand length, hand width, hand depth, hand palm, and wrist circumference were measured. The hand was exposed to different bath temperatures (5 °C, 25 °C, and 45 °C) and hand grip strength was measured using a Jamar hydraulic hand dynamometer with and without wearing the gloves (chemical protection glove, rubber insulating glove, anti-vibration impact glove, cotton yarn knitted glove, and RY-WG002 working glove). The data were analyzed using the Shapiro–Wilk test, Pearson correlation coefficient, Tukey test, and analysis of variance (ANOVA) of the within-subject design analysis. The results showed that wearing gloves significantly affected the maximum grip strength. Wearing the RY-WG002 working glove produced a greater reduction on the maximum grip when compared with the bare hand, while low temperatures (5 °C) had a significant influence on grip when compared to medium (25 °C) and high (45 °C) hand skin temperatures. In addition, participants felt more discomfort in both environmental extreme conditions. Furthermore, they reported more discomfort while wearing neoprene, rubber, and RY-WG002 working gloves.
... The heat and moisture transfer capability is also affected by the fabric structures because different fabric structures have different levels of porosity, resulting in different volumes of still air entrapped in the fabric [118]. On average, knitted fabrics entrap more still air compared with woven fabrics, although the yarn density of weaving and knitting is a factor as well. ...
Full-text available
Thermal comfort property is one of the most important properties to fibrous materials, and it will affect the human thermophysiological responses. The thermal comfort property of fibrous materials depends heavily on their heat and moisture transfer capability. To characterize the heat and moisture transfer property, different techniques and instruments have been developed. Also, different techniques have been incorporated into clothing systems to improve the clothing comfort property by cooling or heating the microclimate between the human body and clothing systems. This chapter reviews the human thermoregulatory system and the heat and moisture transfer properties of fabrics and full‐scale clothing. Innovative personal cooling strategies used to improve clothing wear comfort are also described. Finally, the future trends on the development of new fibrous materials and performance measurement techniques are addressed.
The sleep–wake cycle is regulated by circadian Process C and homeostatic Process S. Selective thermal stimulation (STS) of the cervical spine region enhances glabrous skin blood flow (GSBF) and augments body heat dissipation to increase distal‐to‐proximal skin gradient (DPG) causing decrease of core body temperature (CBT), which can shorten sleep onset latency (SOL) and improve sleep quality. A total of 11 young healthy/normal sleeper males challenged to go to bed (lights‐off) 2 h earlier than usual were subjected in a randomised order to non‐consecutive treatment and control night‐time sleep sessions. The treatment night entailed activation of a dual‐temperature zone mattress with a cooler centre and warmer periphery plus STS pillow that applied mild heating to the cervical spinal skin for 30 min after lights‐off for sleep. During the first 30 min after lights‐off, GSBF (mean [standard error (SE)] Δ = 49.77 [19.13] perfusion units, p = 0.013) and DPG (mean [SE] Δ = 2.05 [0.62] °C, p = 0.005) were significantly higher and CBT (mean [SE] Δ = –0.15 [0.07] °C, p = 0.029) was significantly lower in the treatment than control night, while there was no significant difference in these variables during the 45 min prior to lights‐off (baseline). Moreover, SOL was significantly reduced (mean [SE] Δ = –48.6 [23.4] min, p = 0.032) and subjective sleep quality significantly better (p < 0.001) in the treatment than control night. In conclusion, the novel sleep facilitating system comprised of the STS pillow plus dual‐temperature zone mattress induced earlier increase in GSBF and DPG and earlier decline in CBT. This resulted in statistically significant shortened SOL and improved overall sleep quality, thereby reducing sleep pressure of Process S, even under the challenging investigative protocol requiring participants to go to sleep 2 h earlier than customary.
Hand and forearm muscles contribute significantly in grip force execution during routine and industrial activities. Industrial gloves are used in various small-scale industries for safety purpose. However, the use of hand gloves may lead to the change in grip strength. The present study has been designed to investigate the effect of hand glove’s material on hand grip strength of workers employed in various Small and Medium Enterprises (SMEs). During this study, to record the strength of workers’ hand grip while performing work using different gloves, a digital hand grip dynamometer was used. Statistical test one-way ANOVA was applied to analyze the collected data. From the analysis of data, it can be concluded that there are significant differences among the grip strength means with various glove’s material at the 0.05 level of significance. It is also observed that fabric gloves give best grip strength; however, there are limitations in its use.
Full-text available
The association between the footwear microclimate and microbial community on the foot plantar skin was investigated by experiments with three participants. Novel methods were developed for measuring in-shoe temperature and humidity at five footwear regions, as well as the overall ventilation rate inside the footwear. Three types of footwear were tested including casual shoes, running shoes, and perforated shoes for pairwise comparison of footwear microclimate and corresponding microbial community on the skin. The major findings are as follows: (1) footwear types make a significant difference to in-shoe temperature at the instep region with the casual shoes sustaining the warmest of all types; (2) significant differences were observed in local internal absolute humidity between footwear types, with the casual shoes sustaining the highest level of humidity at most regions; (3) the perforated shoes provided the highest ventilation rate, followed by running and casual shoes, and the faster the gait, the larger the discrepancy in ventilation rate between footwear types; (4) the casual shoes seemed to provide the most favorable internal environment for bacterial growth at the distal plantar skin; and (5) the bacterial growth at the distal plantar skin showed a positive linear correlation with the in-shoe temperature and absolute humidity, and a negative linear correlation with the ventilation rate. The ventilation rate seemed to be a more reliable indicator of the bacterial growth. Above all, we can conclude that footwear microclimate varies in footwear types, which makes contributions to the bacterial growth on the foot plantar skin.
Full-text available
A three-dimensional (3D) multi-segment hand-specific thermoregulation model was developed as a fundamental tool for spatial and temporal skin temperature prediction. Cold-induced vasodilation in fingers was simulated by superimposing symmetrical triangular waveforms onto the basal blood flow. The model used realistic anatomical, physiological, and thermo-physical in formation of a standard human hand and forearm. The inhomogeneity of hand thermal and physiological properties was considered by dividing it into 17 segments: palm, dorsal, forearm, and five fingers, with each finger subdivided into fingertip, middle segment, and finger root except for the thumb, which has no middle segment. Each segment contained a bone core and an outer soft tissue layer. 3D scanning technology was employed to develop the geometrically realistic model of the hand and the bone. The thermo-physical and physiological properties of each segment and layer were obtained from a photogrammetric analysis of anatomic atlases and from literature. Heat transfer throughout the hand by metabolism, blood perfusion, and conduction between the tissue was considered. Heat loss by convection and radiation from the skin and the protective effects of gloves were also included in the model. The model showed good agreement with experimental data from the literature. The developed 3D hand model fills the knowledge gap and builds a bridge between existing knowledge of the hand’s physiology and its application, providing a science-based tool for decision making. The understanding from model studies may also help enhance the wearer’s working efficiency, safety, health, and wellbeing while working in indoor and outdoor cold environments.
Full-text available
Background The human foot typically changes temperature between pre and post-locomotion activities. However, the mechanisms responsible for temperature changes within the foot are currently unclear. Prior studies indicate that shear forces may increase foot temperature during locomotion. Here, we examined the shear-temperature relationship using turning gait with varying radii to manipulate magnitudes of shear onto the foot. Methods Healthy adult participants ( N = 18) walked barefoot on their toes for 5 minutes at a speed of 1.0 m s ⁻¹ at three different radii (1.0, 1.5, and 2.0 m). Toe-walking was utilized so that a standard force plate could measure shear localized to the forefoot. A thermal imaging camera was used to quantify the temperature changes from pre to post toe-walking (ΔT), including the entire foot and forefoot regions on the external limb (limb farther from the center of the curved path) and internal limb. Results We found that shear impulse was positively associated with ΔT within the entire foot ( P < 0.001) and forefoot ( P < 0.001): specifically, for every unit increase in shear, the temperature of the entire foot and forefoot increased by 0.11 and 0.17 °C, respectively. While ΔT, on average, decreased following the toe-walking trials (i.e., became colder), a significant change in ΔT was observed between radii conditions and between external versus internal limbs. In particular, ΔT was greater (i.e., less negative) when walking at smaller radii ( P < 0.01) and was greater on the external limb ( P < 0.01) in both the entire foot and forefoot regions, which were likely explained by greater shear forces with smaller radii ( P < 0.0001) and on the external limb ( P < 0.0001). Altogether, our results support the relationship between shear and foot temperature responses. These findings may motivate studying turning gait in the future to quantify the relationship between shear and foot temperature in individuals who are susceptible to abnormal thermoregulation.
Full-text available
The paper presents the prediction of elastic behaviour of woven fabric produced from stretch yarn. The particularity of the stretch fabric included in the research was the elastane filaments incorporated in the yarn in the warp and weft direction. The goal of the research was to analyse the relation between the value of elastane content in the yarn and elastic recovery after longer exposing to the specified extension. For the experimental part of research, the 115 wool woven fabrics in the twill weave with elastane yarn were analysed with the different percentage of elastane in the yarn, similar thickness and mass. The data mining technique was chosen to analyse the relation between percentage of elastane content in the yarn and elastic recovery after one hour exposing the fabric to the specified extension. The research results show the linear relation between the value of elastane content in the yarn and elastic recovery of fabric. Keywords: fabric with elastane yarn, elastic recovery, regression and model tree
The distribution of cutaneous thermosensitivity has not been determined in humans for the control of autonomic or behavioural thermoregulation under open-loop conditions. We therefore examined local cutaneous warm and cool sensitivities for sweating and whole-body thermal discomfort (as a measure of alliesthesia). Thirteen males rested supine during warming (+4 degrees C), and mild (-4 degrees C) and moderate (-11 degrees C) cooling of ten skin sites (274 cm(2)), whilst the core and remaining skin temperatures were clamped above the sweat threshold using a water-perfusion suit and climate chamber. Local thermosensitivities were calculated from changes in sweat rates (pooled from sweat capsules on all limbs) and thermal discomfort, relative to the changes in local skin temperature. Thermosensitivities were examined across local sites and body segments (e.g. torso, limbs). The face displayed stronger cold (-11 degrees C) sensitivity than the forearm, thigh, leg and foot (P = 0.01), and was 2-5 times more thermosensitive than any other segment for both sudomotor and discomfort responses (P = 0.01). The face also showed greater warmth sensitivity than the limbs for sudomotor control and discomfort (P = 0.01). The limb extremities ranked as the least thermosensitive segment for both responses during warming, and for discomfort responses during moderate cooling (-11 degrees C). Approximately 70% of the local variance in sudomotor sensitivity was common to the alliesthesial sensitivity. We believe these open-loop methods have provided the first dear evidence for a greater facial thermosensitivity for sweating and whole-body thermal discomfort.
This investigator briefly reviews the literature on the cerebral cortex. He discusses his observations on the stimulation of this area in conscious patients. Response is obtained most easily from the vicinity of the fissure of Rolando, but the responses were not obtained from exactly fixed areas. Penfield describes vocalization which he produced with the use of a thyratron stimulator, especially when area 12 was stimulated. Simple movements appeared to be involuntary in nature. Sensation, when produced electrically, was referred to the periphery but unexplained. In the dream state of an epileptic patient, a hallucination was presented by discharge within one portion of the cerebral cortex, but the patient retained insight into his real environment since other portions of the cortex retained their normal functions. Penfield supports the view of Hughlings Jackson that the sensorimotor cerebral cortex represents only a middle level of integration. There seems to be no reason why the neural mechanism of consciousness should migrate outward into the newer exfoliated hemisphere with the acquisition of man's new skills and new adjustments to his environment. This level of integration may lie below the cortex and above the midbrain. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Heat strain in aircrew is exacerbated when personal protective equipment is worn, due to the restriction of sweat evaporation. The most realistic solution to this problem in the military would be to adopt a cooling garment that removed heat from the body surface by direct conduction. Previous work has indicated that heat may be extracted more effectively from the limbs than the torso of the body: the approach traditionally used in conductive cooling garments. This experiment was conducted to test the hypothesis that heat extraction rates when a hand or foot was cooled were greater than that for cooling a forearm or lower leg. Twenty male subjects undertook a repeated-measures study in which heat strain was induced by exercising in a hot climate followed by natural cooling (control) or the application of cooling to the hand, foot, forearm or lower leg. Cooling interventions were undertaken by immersing the site in water at 10°C, but avoiding direct contact with the water by using a plastic bag. Cooling rates were determined from changes in mean body temperature calculated from insulated auditory canal and mean skin temperatures. Mean body temperature and heart rate fell at faster rates in all water-cooling conditions compared to the control (p<0.05). The hand was the most effective and the lower leg the least effective, with forearm and foot being similar and intermediate to these two (p<0.05). Assuming that the cooling rate for two hands is approximately double the rate of cooling for a single hand, and similarly for the other body sites, cooling both hands would extract heat at up to 200 W, similar to the rate of metabolic heat production of rotary-wing aircrew during flight. Cooling the other sites would cool at between 120 and 155 W. It is not known if the cooling achieved using multiple sites would be additive.
It is generally accepted that the palmar (volar) and dorsal surfaces of human hands display different sudomotor responses to mental or thermal stimuli. We tested the hypothesis that, during thermal stimulation, secretion from the dorsal surfaces would always exceed that from the volar aspect of the hand. Sweat secretion from 10 hand sites and the forehead was examined (ventilated capsules) in 10 subjects during passive heating (climate chamber: 36 degrees C, 60% relative humidity, water-perfusion suit: 40 degrees C) immediately followed by incremental cycling to volitional fatigue. This treatment significantly increased core temperature (39.3 degrees C), heart rate (178 bpm), and sweat rate at all sites. Mean sweat secretion during exercise was greater at the forehead (2.90 mg x cm(-2) x min(-1); +/- 0.19) than the hand (1.49 mg x cm(-2) min(-1); +/- 0.27). While no significant differences in sweating were observed among dorsal sites, a nonuniform secretion pattern was observed across the volar surface, with sweating at the palm being the lowest, and that from the volar aspect of the distal phalanges being equivalent to the dorsal hand. These differences became more evident as exercise progressed. Mean hand sweat rate during exercise was 41.7 ml x h(-1), with sweating from the palm accounting for only about 6% of sweat secretion. Sweat secretion from both the palmar and dorsal surfaces of the hand increases during exercise in the heat, although this occurs in a nonuniform fashion. It is possible that a greater sweat gland density on the fingers may account for variations across the volar surface. However, higher dorsal sweating with lower gland counts (high glandular flow) may be attributable to either larger sweat glands, or to a greater cholinergic sensitivity of these glands.
Three men exercised on a bicycle ergometer at 30, 50, asd 70 per cent of maximal aerobic power in ambient temperatures of 15, 25, and 35 degrees C with water vapor pressure less than 18 Torr. Exercies was used to vary internal temperature during as experiment, and different ambient temperatures were used to vary skin temperatures independently of internal temperature. Finger temperature was fixed at about 35.7 degrees C. Espohageal temperature (Tes) was measured with a thermocouple at the level of the left atrium, and mean skin temperature (Tsk) was calcualted from a weighted mean of thermocouple temperatures at eight skin sites. Finger blood flow (BF) was measured by electrocapacitance plethysmography. Although some subjects showed small and equivocal vasomotor effects of exercise, our data are well accounted for by an equation of the form BF equal to alTes + a2Tsk + b, independent of exercise intensity. For these subjects, the ratios a1/a2 (5.9, 8.6, 9.4) were similar to the ratios of the corresponding coefficients recently reported for thermaoregulatory sweating (8.6, 10.4) and for forearm blood flow (9.6).