Hemihidrosis due to skin pressure with particular remarks on the intensity and area of the pressure stimuli

Effects of individual characteristics and local body functions on sweating response: A review

In this study, we conducted a literature review to deepen our understanding of the sweating response of the thermoregulatory system, focusing on the influence of individual characteristics and local body functions. Among the factors related to individual characteristics, improvement in aerobic fitness had a positive effect on the sweating response, whereas aging exerted an inhibitory effect. Short-term artificial acclimation and seasonal heat acclimatization promoted sweating, whereas long-term geographical acclimatization suppressed sweating. Male exhibited higher sweat rates than female when the metabolic heat production was high. Individuals with smaller surface area-to-mass ratios tended to have higher sweat rates than those with larger ratios. Regarding local body functions, sweat distribution in the resting state showed high regional sweat rates in the lower limbs and torso, with higher values in the lower limbs when in the supine position and higher values in the torso when in the seated position. During exercise, the regional sweat rates was high in the torso, whereas the limbs exhibited relatively low sweat rates. These differences in sweat distribution stem from the thermoregulatory potential of each body region, which aims to efficiently regulate body temperature. Local effects have only been examined in the thigh and forearm, with temperature coefficient Q10 ranging from 2 to 5. Only the forehead showed significantly high thermosensitivity among all body regions.

Pillow Support Model with Partitioned Matching Based on Body Pressure Distribution Matrix

(1) Objective: Sleep problems have become one of the current serious public health issues. The purpose of this research was to construct an ideal pressure distribution model for head and neck support through research on the partitioned support surface of a pillow in order to guide the development of ergonomic pillows. (2) Methods: Seven typical memory foam pillows were selected as samples, and six subjects were recruited to carry out a body pressure distribution experiment. The average value of the first 10% of the samples in the comfort evaluation was calculated to obtain the relative ideal body pressure distribution matrix. Fuzzy clustering was performed on the ideal matrix to obtain the support surface partition. The ideal body pressure index of each partition was calculated, and a hierarchical analysis of each partition was then performed to determine the pressure sensitivity weight of each partition. Using these approaches, the key ergonomic node coordinates of the partitions of four different groups of people were extracted. The ergonomic node coordinates and the physical characteristics of the material were used to design a pillow prototype. Five subjects were recruited for each of the four groups to repeat the body pressure distribution experiment to evaluate the pillow prototype. (3) Results: An ideal support model with seven partitions, including three partitions in the supine position and four partitions in the lateral position, was constructed. The ideal body pressure distribution matrix and ideal body pressure indicators and pressure sensitivity weights for each partition were provided. The pillow that was designed and manufactured based on this model reproduced the ideal pressure distribution matrix evaluated by various groups of people. (4) Conclusion: The seven-partition ideal support model can effectively describe the head and neck support requirements of supine and lateral positions, which can provide strong support for the development of related products.

Revisiting the dermatomal recruitment of, and pressure-dependent influences on, human eccrine sweating

Herein we describe two experiments in which the recruitment and pressure-induced modifications of human eccrine sweating were investigated. In one experiment, the longstanding belief that glandular recruitment follows a gradual, caudal-to-rostral (dermatomal) recruitment pattern was re-evaluated. The onset of sweating was simultaneously determined (ventilated capsules) from four spinal (dermatomal) segments (forehead, dorsal hand, lower chest and dorsal foot) during the passive heating of supine participants (N = 8). No evidence was found to support either dermatomal or simultaneous glandular recruitment patterns. Instead, the results were more consistent with individualised (random) patterns of regional activation (P > 0.05), with significant time delays among sites. Such delays in the appearance of discharged sweat may reflect differences in neurotransmitter sensitivity, precursor sweat production or ductal reabsorption. In the second experiment, the pressure-induced hemihidrotic reflex (contralateral sudomotor enhancement) was revisited, using pressures applied over 10 cm² areas of the chest (left side: 6 N cm^-2) and left heel (3 N cm^-2) during both supine and seated postures (N = 12). Participants were passively heated and thermally clamped before pressure application. Hemihidrosis was not observed from the contralateral surfaces within the same (chest) or lower spinal segments (abdomen; both P > 0.05) during chest pressure, but a generalised enhancement followed heel pressure when supine. We suggest that previous observations of hemihidrosis possibly resulted from elevated heat storage, rather than a neural reflex. Chest pressure significantly inhibited ipsilateral sweating (forehead, hand, chest; all P < 0.05), and that influence is hypothesised to result from interactions between ascending mechanoreceptor afferents and the descending sudomotor pathways.

Effects of pressure exerted on the skin by elastic cord on the core temperature, body weight loss and salivary secretion rate at 35 degrees C

Effects of pressure exerted on the skin by elastic cord on the core temperature, body weight loss and salivary secretion rate were studied under conditions of ambient temperature of 35 degrees C and a relative humidity of 60%. Twelve healthy females, aged 18-23 years, served as subjects. The subjects entered a bioclimatic chamber and rested quietly in a chair for 80 min. Then, skin pressure was exerted by applying elastic cord (8.5 mm wide) to six different skin areas, such as axilla, under-bust, waist, inguines, thighs and ankles. The values of skin pressure by elastic cord ranged from 11.9 to 33.3 g/cm(2). In the control experiment, wrapping with an elastic cord was loosely performed without any skin pressure. Rectal and skin temperatures, body weight loss by sweating and salivary secretion rate were measured throughout the 160 min experimental period. Core temperature increased more significantly under pressure exerted on the skin. Body weight loss by mainly sweating and salivary secretion rate were significantly suppressed under pressure exerted on the skin. We discussed the physiological mechanisms in terms of suppression of central nervous activity as to why significant increase of core temperatures, inhibition of body weight loss mainly by sweating and of salivary secretion rate occurred, and furthermore practical significance of these findings for impairment of digestion, swallowing, vocalizing, defense against disease bacteria and sport activity.

Somatotopic arrangement of sudomotor axon reflex sweating in humans

BACKGROUND

Impaired sweating may be one of the first symptoms in neuropathies, and therefore the evaluation of sweating might facilitate their early detection. Sudomotor axon reflexes can be quantified by two different methods: quantitative sudomotor axon reflex testing (QSART) measures the amount of local sweating, whereas staining with the iodine starch reaction assesses the extension of the sudomotor axon reflex area. The aim of our study was to compare both tests at three different sites on the leg: foot, lower leg and thigh.

METHODS

QSART and iodine starch staining after iontophoretic stimulation with acetylcholine were performed on 15 male volunteers (mean age: 25; range 24-27 years) on the left resp. the right leg during a single session.

RESULTS

QSART response, measured as area under the curve (AUC), was maximal at the lower leg (911 AUC), smaller at the dorsum of the foot (585 AUC) and even smaller at the thigh (480 AUC). The difference between lower leg and thigh was significant (p < 0.02). The sudomotor axon reflex area was also biggest on the lower leg (39 cm(2)) followed by the foot dorsum (28 cm(2)), and then the thigh (16 cm(2)). The differences between lower leg and thigh as well as between lower leg and foot were significant (p < 0.01, resp. p < 0.04). The size of the sudomotor axon reflex areas and QSART responses were correlated (p < 0.01).

CONCLUSIONS

QSART and sudomotor axon reflex areas had similar somatotopic arrangements in human skin. The bigger the axon reflex area was the stronger the QSART response was. This indicates that the size of the innervation territories of sudomotor fibres covaries with the amount of local sweat production. The latter is a surrogate for increased sweat gland density or capacity in skin areas of dense sudomotor innervation.

Effects of exercise intensity, posture, pressure on the back and ambient temperature on palmar sweating responses due to handgrip exercises in humans

We have, by using newly developed ratemeters, attempted to examine the effects of exercise intensity, posture, pressure on the skin of the back, and ambient hyperthermic conditions (approximately 30 degrees C) on the 5-s handgrip exercise-mediated responses of active palmar sweating in humans. Thirty-five right-handed male (n=5) and female (n=30) volunteer students (20.2+/-1.3 years old) participated in the present study. Oral explanation of only the isometric handgrip exercise (IHG) caused a rapid and oscillatory response (pre-operational) of active palmar sweating in almost all subjects (10 of 14 subjects). Performing the IHG for 5-s caused a significant increase in active sweating rate (operation-mediated response) in both ipsi- and contra-lateral palmar surfaces of the thumbs of all subjects. The operation-mediated responses of active palmar sweating to the IHG were reproducible, resulting in no habituation. The increase of operation-mediated responses to the IHG was dependent upon exercise intensity (100-25% maximal voluntary contractions). The IHG-mediated ipsi- and contra-lateral responses of active palmar sweating were significantly decreased by changing the body posture from a seated to a supine position or by pressing the skin of the back. Ambient hyperthermic conditions (approximately 30 degrees C) for 60 min also resulted in a significant decrease in the back-pressure-dependent reduction of the operation-mediated responses of active palmar sweating to the IHG. In conclusion, in order to optimize the precision and reproducibility of clinical tests involving palmar sweating responses, it is important that subjects maintain a constant handgrip force and posture and that ambient temperature be kept under normothermic conditions.

Occurrence of the spinal reflex due to skin pressure in sudomotor and cutaneous vasoconstrictor nerve system of humans

The effects of skin pressure applied to one side of the waist on sudomotor and vasoconstrictor nerve activity were compared with the effects on sweating and cutaneous blood flow in humans. The sweat rate and cutaneous blood flow were measured on left and right dorsal feet. Skin sympathetic nerve activity (SSNA) was recorded by microneurography from a microelectrode inserted in left and right peroneal nerves. Skin pressure was applied in a supine position to the area over the left or right anterior superior iliac spine under warm (T(a): 30-36 degrees C) and cool (T(a): 19-23 degrees C) conditions. Sudomotor and vasoconstrictor bursts were identified for quantitative analysis. The skin pressure increased the contralateral/ipsilateral ratio of the sweat rate. It also increased the contralateral/ipsilateral ratio of the cutaneous blood flow and the contralateral/ipsilateral ratio of the sudomotor burst amplitude. However, skin pressure did not induce any significant changes in the contralateral/ipsilateral ratio of the vasoconstrictor burst amplitude. The results indicate that an asymmetrical reflex effect of skin pressure on vasoconstrictor nerve activity was absent, suggesting that, whereas the ipsilateral suppression of sweating elicited by skin pressure was mediated by the sudomotor nerve system, the ipsilateral suppression of cutaneous blood flow was not mediated by the vasoconstrictor nerve system. Thus, the occurrence of the spinal reflex due to skin pressure is not uniform between the sudomotor and the vasoconstrictor nerve systems, which represent different organizations at the level of spinal cord.

Arithmetic calculation, deep inspiration or handgrip exercise-mediated pre-operational active palmar sweating responses in humans

We examined the effects of repetitive mental stimulation such as arithmetic calculations with sequential subtraction or physical tasks such as handgrip exercise and deep breathing on active palmar sweating responses in humans. Thirty-three healthy, male and female volunteer students (20.4+/-2.1 years) participated in the present study. The responses of active palmar sweating were evaluated by using the newly developed ratemeter. The galvanic skin response (GSR) was also recorded in 10 out of 33 subjects. The oral explanation of the stimulation or tasks caused a rapid and wavy active palmar sweating response. The pre-operational responses of active palmar sweating to the stimulation or tasks were also observed by the GSR recording. The mental stimulation- and physical tasks-mediated pre-operational responses were significantly reduced by the trials. The mental stimulation or physical tasks also caused a rapid and oscillatory response of active palmar sweating during operation of the stimulation or tasks. The operation-mediated responses to physical tasks were observed ipsilaterally and contralaterally. The physical task-mediated responses were also reproducible, resulting in no habituation. In contrast, the operation-mediated responses to mental stimulation were reduced significantly by the trials, resulting in a marked habituation. The findings suggest that the mental stimulation- and physical tasks-mediated pre-operational responses of active palmar sweating obtained by using the newly developed ratemeter will make useful tests for evaluating neuronal activity of limbic system including amygdala, sympathetic sudomotor activity in the palmar skin and functional properties of the palmar sweat glands.

Effects of skin pressure applied by cuffs on resting salivary secretion

The effects of pressure applied by cuffs to the abdomen, thighs and legs on resting salivary flow rate and digestive function of saliva were investigated in 9 healthy female students, aged 18 to 33 yrs (Experiment I) in a climatic chamber (Ta: 28 degrees C, RH: 50%). Each participant changed from street clothing into loose-fitting experimental garments so as to avoid any skin pressure on the body, and sat calmly in a reclining chair throughout the experimental period (195 min). After 90 min (FREE period), the physiological effects of skin pressure applied by their own clothing disappeared, and skin pressure was applied for the next 60 min to the abdomen (40 mmHg) and thighs (40 mmHg) then to the legs (60 mmHg) by the use of air-inflated cuffs (PRESSURE period). During the next 45 min, the skin pressure was again removed by letting the air of the cuffs out (FREE' period). The resting salivary flow rate was significantly suppressed while the skin pressure was applied by the cuffs. The digestive time for starch investigated in terms of the iodine starch reaction was longer with the skin pressure than without. The concentration of amylase measured in 20 female participants aged 21 to 23 yrs, decreased with skin pressure applied by the usage of the rubber tape (Experiment II). These results suggest that the pressure applied to the body can influence the digestive response by decreasing the amount of saliva via the autonomic nervous system.

Contralateral temperature changes of the finger surface during video endoscopic sympathectomy for palmar hyperhidrosis

One hundred and eight consecutive patients with primary palmar hyperhidrosis were surgically managed by coagulation of bilateral T2 sympathetic ganglia using video thoracoscopic techniques. Patients were divided into two groups. In the first group (N = 46), finger surface temperature of the ipsilateral index finger was recorded before and after T2 ganglionectomy. The average increase of post-operative temperature was 2.74 +/- 0.27 degrees C (mean +/- SE) on the right side and 2.67 +/- 0.33 degrees C on the left (P < 0.05). The significant rise of temperature resulting from sympatholytic vasodilatation was only noted in cases of exact ablation of the T2 ganglion. In the second group (N = 62), surface temperatures of both index fingers were monitored and recorded simultaneously. These patients were arbitrarily subdivided into Group 2-A (N = 29) when right side ganglionectomy was performed first and Group 2-B (N = 33) when left side ganglionectomy was done initially. After the first ganglionectomy was completed, an ipsilateral increase with a contralateral decrease of temperature was observed; the average increase of temperature was 1.92 +/- 0.35 degrees C and 2.19 +/- 0.30 degrees C, and the average decrease was 1.50 +/- 0.51 degrees C and 1.67 +/- 0.39 degrees C for Group 2-A and 2-B respectively (P < 0.05). The authors postulate that a cross-inhibitory effect by the post-ganglionic neurons innervating blood vessels of the upper extremities may exists in humans and this effect is released after ganglionectomy, resulting in contralateral vasoconstriction and decrease of finger surface temperature.

The influence of monocular viewing on heart period variability

Monocular viewing seems to differentially activate the cerebral hemispheres. Viewing with only one eye is accompanied by a relatively greater activation of the contralateral hemisphere. In this study heart periods were measured during binocular, left and right monocular viewing in 29 right-handed males. Power spectral analysis of heart period variability showed that the amount of heart rate fluctuations in the 0.07-0.13 Hz frequency range (the mid-frequency peak of the spectrum) depends on the viewing eye. Only viewing with the left eye produced a significant increase of the mid-frequency peak. It is known that sympathetic activity contributes strongly to the mid-frequency component of the heart rate. Therefore, it is concluded that the effects of left monocular viewing result in an increased sympathetic influence on the sinoatrial node.

Local autonomic failure affecting a limb

Three patients are described who presented with autonomic failure affecting predominantly one limb. Physiological studies revealed that there was sweating loss in the limb which appeared to be due to a preganglionic autonomic lesion and not to a sweat gland abnormality. In all three patients there was also evidence of failure of vasomotor control. There was no evidence of more generalised autonomic failure or neurological deficit. In two patients the condition appeared to be static and, according to the patients' accounts was life long. In the third the sweating loss was present for three years prior to pain loss becoming evident from C2/3 to T1 on the same side as the sweating loss. These patients, together with two recent case reports, indicate that isolated local autonomic failure, probably from a discrete cord lesion, can be a cause of presenting symptoms related to sweating loss or to change in temperature in a limb.