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1.
Nat Commun ; 15(1): 2991, 2024 Apr 06.
Article in English | MEDLINE | ID: mdl-38582753

ABSTRACT

All-solid-state batteries using Si as the anode have shown promising performance without continual solid-electrolyte interface (SEI) growth. However, the first cycle irreversible capacity loss yields low initial Coulombic efficiency (ICE) of Si, limiting the energy density. To address this, we adopt a prelithiation strategy to increase ICE and conductivity of all-solid-state Si cells. A significant increase in ICE is observed for Li1Si anode paired with a lithium cobalt oxide (LCO) cathode. Additionally, a comparison with lithium nickel manganese cobalt oxide (NCM) reveals that performance improvements with Si prelithiation is only applicable for full cells dominated by high anode irreversibility. With this prelithiation strategy, 15% improvement in capacity retention is achieved after 1000 cycles compared to a pure Si. With Li1Si, a high areal capacity of up to 10 mAh cm-2 is attained using a dry-processed LCO cathode film, suggesting that the prelithiation method may be suitable for high-loading next-generation all-solid-state batteries.

2.
BMC Complement Med Ther ; 23(1): 73, 2023 Mar 06.
Article in English | MEDLINE | ID: mdl-36879223

ABSTRACT

OBJECTIVE: The objective of this study was to determine the effect of music therapy as an alternative treatment on depression in children and adolescents with attention-deficit hyperactivity disorder (ADHD) by activating serotonin (5-HT) and improving stress coping ability. METHODS: This study is designed based on randomization method. A total of 36 subjects participated in the experiment, consisting of an ADHD control group (n = 18) and ADHD music therapy group (n = 18). The ADHD control group received standard care, while the ADHD music therapy group received music therapy and standard care. The ADHD music therapy group received both active music therapy (improvisation) and receptive music therapy (music listening) for 50 minutes, twice a week, for 3 months: a total of 24 times. From a neurophysiological perspective, changes in depression and stress were tracked by measuring 5-HT secretion, cortisol expression, blood pressure (BP), heart rate (HR), and CDI and DHQ psychological scales. RESULTS: The ADHD music therapy group's 5-HT secretion increased (p < 0.001), whereas cortisol expression (p < 0.001), BP (p < 0.001) and HR (p < 0.001) decreased. The CDI and DHQ psychological scales also showed positive changes (p < 0.01 and p < 0.001, respectively). However, the ADHD Con G's (who did not receive music therapy) 5-HT secretion did not increase, whereas cortisol expression, BP, and HR did not decrease. In addition, the CDI and DHQ psychological scales did not display positive changes. CONCLUSIONS: In conclusion, the application of music therapy as an alternative treatment for ADHD children and adolescents showed positive neurophysiological and psychological effects. Therefore, this study would like to propose a new alternative to medicine for preventing and treating depression through various uses of music therapy.


Subject(s)
Attention Deficit Disorder with Hyperactivity , Music Therapy , Adolescent , Child , Humans , Adaptation, Psychological , Attention Deficit Disorder with Hyperactivity/therapy , Depression/therapy , Hydrocortisone , Serotonin
4.
Front Nutr ; 9: 1051828, 2022.
Article in English | MEDLINE | ID: mdl-36570158

ABSTRACT

Objectives: To determine whether drinking coffee with caffeine accelerates the sympathetic response to acetylcholine (ACh). Methods: Tests were performed twice at 1-week intervals following the intake of coffee. Subjects were randomly divided into two groups: Group A was administered 16 fluid oz of water (CON), while Group B was given 16 fluid oz of coffee (Coffee). After 1 week, Group A was administered 16 fluid oz of coffee (Coffee), while Group B was given 16 fluid oz of water (CON). The quantitative sudomotor axon reflex test (QSART) was performed after intake of coffee and water and a 40 min break. QSART with iontophoresis and 10% ACh was performed to determine axon reflex (AXR) mediated with and without iontophoresis [AXR (1) and AXR (2), respectively], and directly activated sweating (DIR). Results: The sweat onset time of the AXR was shorter in the Coffee compared with the CON (p < 0.05). The sweat rates in AXR (1) AXR (2) and DIR were significantly higher in the Coffee than in the CON (p < 0.05, p < 0.05, p < 0.01, respectively). In addition, the Coffee showed significantly higher density of activated sweat glands and activated sweat gland output than the CON (p < 0.05, p < 0.01, respectively). The overall results of this study showed that coffee intake could stimulate higher activation in both AXR and DIR sweat responses. Conclusion: Coffee intake can improve sweating sensitivity in both the AXR and DIR by the contribution of caffeine contained in coffee. This suggests that other compounds in coffee may not inhibit the sympathetic response to ACh. Therefore, coffee may be clinically worth considering as a supplement for the activation of the cholinergic and sudomotor function.

5.
Ann Occup Environ Med ; 34: e28, 2022.
Article in English | MEDLINE | ID: mdl-36452252

ABSTRACT

Background: Haenyeo is a woman who has the job of collecting seafood in the Jeju Sea at an average temperature of 13°C-14°C. The purpose of this study was to examine the cold acclimatization and occupational characteristics of Haenyeo through biomarkers such as orexin and irisin related to heat generation in the body. Methods: Twenty-one Haenyeo and 25 people with similar age, body type, and body mass index were selected as the control group (Control G). In the cold exposure experiment, a climate chamber was set to 5°C and both feet were immersed in a 15°C water tank for 30 minutes. Tympanic temperature (Tty) and skin temperature (Tsk) were measured, and the mean body temperature (mTb) was calculated. Blood samples were collected before and immediately after the examination. Orexin and irisin levels were analyzed. Results: Orexin levels were elevated after cold stimulation from 12.17 ± 4.44 to 12.95 ± 4.53 ng/mL (Haenyeo group [Haenyeo G], p < 0.01) and 10.37 ± 3.84 to 11.25 ± 4.02 ng/mL (Control G, p < 0.001). Irisin levels were elevated after cold stimulation from 4.83 ± 2.28 to 5.36 ± 2.23 ng/mL (Haenyeo G, p < 0.001) and 3.73 ± 1.59 to 4.18 ± 2.04 ng/mL (Control G, p < 0.001). The difference between Haenyeo G and Control G values in orexin and irisin appears not only in pre-exposure but also in post-exposure (p < 0.05). Conclusions: Our experimental results suggest that Haenyeo G were relatively superior in cold tolerance to Control G under cold exposure conditions. Haenyeo's cold acclimatization is due to the basic differences in pyrogens regarding body temperature control such as orexin and irisin. This means that Haenyeo are advantageous for cold survival.

6.
Korean J Physiol Pharmacol ; 26(6): 501-509, 2022 Nov 01.
Article in English | MEDLINE | ID: mdl-36302624

ABSTRACT

Irisin is a myokine caused by exercise that improves insulin resistance and weight loss. However, under unfavorable conditions such as air pollution, and during the pandemic, outdoor activities are uncomfortable. Therefore, in this study, the effect of heat therapy (half bath 42 ± 0.5°C for 30 min) on irisin circulation levels as an exercise alternative for middle-aged obese women after menopause was investigated. Subjects were 33 women aged 49.54 ± 6.04 years, with parameters of height, 160.12 ± 4.33 cm, weight, 69.71 ± 7.52 kg, body surface area 1.73 ± 0.13 m2, body mass index, 27.19 ± 3.40 kg/m2. The results suggest that circulating irisin levels showed a significant increase after one-time thermotherapy (TH-1). However, the increase in circulating irisin levels after 15 treatments (TH-15, 5 days/week, 3 weeks) was significantly varied. The level of adiponectin, which increases fatty oxidation to reduce fatty deposition, increased significantly at TH-1, but further increased at TH-15, which was significantly different from the level of TH-1. In addition, the basic serum free fatty acid (FFA) level was significantly increased at TH-15 compared to TH-1. Significant differences were also found in the lipid profile (body mass index, waist circumference, and % body fat). Thermotherapy can significantly increase the tympanic temperature and induce changes in circulating irisin and adiponectin levels. Thus, it resulted in positive changes in FFA and lipid profiles. Therefore, repeated thermotherapy is effective in increasing circulating irisin levels in postmenopausal obese women.

7.
Food Sci Biotechnol ; 31(9): 1207-1212, 2022 Aug.
Article in English | MEDLINE | ID: mdl-35615306

ABSTRACT

Caffeine and orexin can affect awakening, neuroendocrine, and sympathetic nerve function. Our previous study has reported that caffeine intake can increase human body temperature. However, little is known about the combined effects of thermotherapy and caffeine intake on human serum orexin concentrations. Forty-two healthy male subjects with age of 26.72 ± 5.05 years, height of 174.10 ± 7.09 cm, and body weight of 74.68 ± 8.91 kg participated in this study. They were randomly assigned to a control (CON) group (n = 21) and a caffeine (CAFF) group (n = 21). After thermotherapy (half-body immersion in a hot water bath at 42 ± 0.5 °C, circulating orexin level increased more (p < 0.05) in the CAFF group than in the CON group. Positive relationships between mean body temperature and orexin were observed before and after heat stimulation (p < 0.001). Caffeine intake boosted the upregulation of serum orexin concentrations in subjects undergoing thermotherapy.

8.
Chin J Physiol ; 64(5): 211-217, 2021.
Article in English | MEDLINE | ID: mdl-34708712

ABSTRACT

This study aimed to investigate the effect of mealworm (Tenebrio molitor) derived protein supplementation on skeletal muscle atrophy of hindlimb casted immobilized rats. Twenty-four six-week-old male Sprague-Dawley rats were randomly divided into three groups: control sedentary group (CD, n = 8), control diet casting group (CDC, n = 8), and the mealworm-derived protein supplemented casting group (MDC, n = 8). CD and CDC group was supplemented AIN-76G diet and mealworm-derived protein supplemented diet for MDC group was substituted as 5% casein protein to 5% mealworm protein for 5 weeks and left hindlimb casting immobilization using casting tape for CDC and MDC group was done 1 week before sacrifice. After 5 weeks of mealworm supplementation, the soleus muscle weight of the MDC group was significantly higher compared to the CDC group. In addition, the level of muscle protein synthesis factors p-Akt/Akt, p-4EBP1/4EBP1, and p-S6K/S6K significantly increased in the MDC group compared to the CDC group. On contrary, the level of muscle protein degradation factors (MuRF1 and atrogin-1) was significantly lower in the MDC group than that of the CDC group. These results suggest that mealworm-derived protein supplementation may have a significant role in the prevention of skeletal muscle atrophy via stimulation of muscle protein synthesis factors and inhibition of muscle protein degradation factors, and therefore a promising intervention in sarcopenia.


Subject(s)
Tenebrio , Animals , Dietary Supplements , Hindlimb/pathology , Male , Muscle, Skeletal , Muscular Atrophy/pathology , Muscular Atrophy/prevention & control , Rats , Rats, Sprague-Dawley
9.
Science ; 373(6562): 1494-1499, 2021 Sep 24.
Article in English | MEDLINE | ID: mdl-34554780

ABSTRACT

The development of silicon anodes for lithium-ion batteries has been largely impeded by poor interfacial stability against liquid electrolytes. Here, we enabled the stable operation of a 99.9 weight % microsilicon anode by using the interface passivating properties of sulfide solid electrolytes. Bulk and surface characterization, and quantification of interfacial components, showed that such an approach eliminates continuous interfacial growth and irreversible lithium losses. Microsilicon full cells were assembled and found to achieve high areal current density, wide operating temperature range, and high areal loadings for the different cells. The promising performance can be attributed to both the desirable interfacial property between microsilicon and sulfide electrolytes and the distinctive chemomechanical behavior of the lithium-silicon alloy.

10.
Front Physiol ; 12: 675377, 2021.
Article in English | MEDLINE | ID: mdl-34262475

ABSTRACT

High temperatures lead to oxidative stress. The aim of the study was to determine whether heat stimulation-induced hyperthermia can increase the level of circulating irisin. Twenty-one healthy female subjects (age, 26.3 ± 2.71 years; height, 162.1 ± 3.15 cm; weight, 54.2 ± 3.86 kg; and body surface area, 1.57 ± 0.11 m2) not taking contraceptives participated in this study. All experiments were performed individually for each participant when they were in the early proliferative menstrual phase. In an automated climate chamber (25 ± 0.5°C), the heat load was applied via half-body immersion into a hot water bath (42 ± 0.5°C). Five-minutes break was provided every after 5 min of immersion and the total passive heating time was 30 min. Tympanic temperature (Tt y) and skin temperature (Ts) were measured. Mean body temperature (mTb) was calculated. Blood samples were collected before and immediately after immersion. Levels of irisin, cortisol, creatine kinase (CK), and lactate dehydrogenase (LDH) were analyzed. Tty, mTb and serum irisin levels increased after hot water immersion. The blood levels of cortisol, CK, and LDH were also elevated after hot water immersion. Heat stimulation might increase the levels of circulating irisin in humans in response to oxidative stress.

11.
Chin J Physiol ; 63(1): 1-6, 2020.
Article in English | MEDLINE | ID: mdl-32056980

ABSTRACT

The purpose of this study was to quantitatively assess the difference in sudomotor function between healthy males and females in their early twenties by measuring skin surface area and activated sweat gland density (ASGD). The quantitative sudomotor axon reflex test (QSART), a method for evaluating autonomic nervous system activity, was used for quantification. In QSART, the sweat glands are activated directly or indirectly by the subcutaneous application of neurotransmitters, such as acetylcholine, through iontophoresis. This series of mechanisms is called the sudomotor axon reflex. After recording age, height, weight, and several measurements of the forearm, QSART was performed on 101 healthy controls aged 21-26 years to measure ASGD. The mean temperature and humidity on the measurement days were 11.4°C and 58.1% on May 3, 2018, and 14.7°C and 70.3% on May 10, 2018. The result of independent sample t-test showed higher ASGD in women (P < 0.05). The body surface area and the surface area of the forearms were higher in men (P < 0.001), but the number of activated sweat glands was not significantly different according to sex. The activated sweat gland counts of the body and forearms were analyzed through linear regression by age for males and females. Except for the activated sweat gland count of the male body, the analysis showed a tendency to decrease with increasing age but was not statistically significant in any case (P > 0.05). Showing insufficient coefficient of determination (R2), multiple regression analyses with sex and ages did not correct this insignificance between age and activated sweat gland count.


Subject(s)
Sweat Glands , Sweating , Adult , Axons , Female , Humans , Iontophoresis , Male , Reflex , Young Adult
12.
Chin J Physiol ; 62(6): 279-284, 2019.
Article in English | MEDLINE | ID: mdl-31793465

ABSTRACT

The aim of this study was to investigate the plasma dopamine and serum serotonin levels in humans with and without caffeine (CAFF) ingestion during treadmill running exercise. Thirty male volunteers participated in the randomized experiment involving two groups: CON (n = 15, 200 mL of tap water) versus CAFF (n = 15, 3 mg/kg CAFF and 200 mL tap water). After treadmill running, the dopamine level was significantly increased in the CAFF group (P < 0.01) and was significantly higher than in the CON group (P < 0.01). Serotonin was significantly increased in both groups after treadmill running (P < 0.05). However, serotonin levels showed no significant statistical difference between the groups. Prolactin and cortisol were significantly increased in both groups after treadmill running (P < 0.01). However, there was no significant statistical difference between groups. ß-endorphin level was significantly increased in the CAFF group at after treadmill running (P < 0.01) and was significantly higher than in CON after treadmill running (P < 0.01). In conclusion, 3 mg/kg CAFF ingestion before treadmill running stimulated dopamine release without inhibiting serotonin, which may reduce central fatigue.


Subject(s)
Running , Caffeine , Dopamine , Exercise Test , Humans , Male , Men
13.
J Exerc Rehabil ; 15(4): 571-575, 2019 Aug.
Article in English | MEDLINE | ID: mdl-31523679

ABSTRACT

The aim of this study was to investigate the serum serotonin, prolactin, and plasma dopamine levels in humans with and without caffeine ingestion during and after passive heat loading (half immersion in 42°C hot water). Thirty male volunteers participated in the randomized experiment (control group, n=15 vs. caffeine ingestion group, n=15, 3 mg/kg). After 60 min, passive heat loading was conducted for 30 min. Blood samples were collected and assessed for serum serotonin, dopamine and prolactin with and without caffeine during and after passive heat loading. Serum serotonin was significantly lower in the caffeine ingestion group compared to the control group after passive heat loading for 30 min (Post) (P<0.05) and also after 60 min of resting (P<0.01). Dopamine and prolactin were significantly higher in the caffeine ingestion group than in the control group at the Post time point (P<0.001). In conclusion, 3-mg/kg caffeine ingestion prior to passive heat loading can alter central serotonergic and dopaminergic activity, which may contribute to reduced central fatigue and subsequently, to reduced general fatigue. Prolactin responses during passive heat loading were also significantly related to caffeine ingestion in this study. However, the inhibitory effects of dopamine on prolactin by caffeine remain to be elucidated.

14.
Eur J Appl Physiol ; 118(12): 2655-2667, 2018 Dec.
Article in English | MEDLINE | ID: mdl-30209544

ABSTRACT

PURPOSE: We investigated the effects of humidity on regional sweating secretion and active sweat gland density on the scalp during passive heating in hot environments. METHODS: Eight male subjects shaved their heads prior to expose to dry (30%RH; H30%) and humid (85%RH; H85%) conditions at an air temperature of 32 °C. Total sweat rate, local sweat rates (frontal, vertex, temporal, and occipital regions), active sweat glands on the scalp (2 frontal, 2 parietal, 2 temporal, 1 occipital, and 1 vertex), and rectal and skin temperatures were measured during leg immersion in 42 °C water for 60 min. RESULTS: (1) Total sweat rates were greater for H30% (179.4 ± 35.6 g h-1) than for H85% (148.1 ± 27.2 g h-1) (P < 0.05). (2) Scalp sweat secretion tended to be greater in the H85% than the H30%. (3) Head sweat rates were greater on the frontal than on the vertex for both humidity conditions (P < 0.05). (4) Active sweat gland density on the scalp was greater for H85% (82 ± 13 glands cm-2) than for H30% (62 ± 17 glands cm-2) (P < 0.05). (5) No significant difference was found in rectal temperature between H30% and H85%, whereas mean skin temperature was significantly lower for H30% (34.8 ± 0.7 °C) than for the H85% condition (36.0 ± 0.3 °C) (P < 0.05). CONCLUSIONS: These results indicate that the thermoregulatory sweating responses for the scalp region were significantly increased in the hot-humid condition compared to the hot-dry condition. Among the regions on the scalp surface, the vertex was the least sensitive to the change in humidity.


Subject(s)
Environmental Exposure , Hot Temperature , Humidity , Scalp/physiology , Sweat Glands/physiology , Sweating , Adult , Age Factors , Humans , Male , Sex Factors , Skin Temperature , Time Factors , Young Adult
15.
Am J Hum Biol ; 30(3): e23091, 2018 05.
Article in English | MEDLINE | ID: mdl-29341311

ABSTRACT

OBJECTIVE: Tropical natives sweat less and preserve more body fluid than temperate natives, tolerating heat stress. However, the mechanisms involved in such sweating reduction have not been fully elucidated. We examined the sudomotor responses of men of African (n = 36) and Korean (n = 41) ancestry during hot water (43 °C) leg immersion (central sudomotor response). Correlations between mean body temperature, basal metabolic rate (BMR), and sweat rate were also examined. METHODS: All procedures were done in an automated climate chamber. Local skin temperatures and BMR were measured and mean body temperature was calculated. Sweating activities which include evaporative loss rate, sweat onset time, sweat rate, sweat volume, and whole-body sweat loss volume were examined. RESULTS: In the heat load test, Africans showed lower mean body and local skin temperatures than Koreans before and after heating. Before and after heating, BMR declined significantly in Africans, while that of Koreans declined less. Local sweat onset time increased more in Africans than in Koreans. Local evaporative loss rate, local sweat volume, local sweat rate, and whole body sweat loss volume were reduced in Africans compared with Koreans. There were positive associations of mean body temperature and resting BMR with mean sweat rate. CONCLUSION: In conclusion, we observed a larger reduction of sudomotor activity in tropical Africans than in temperate Koreans, which was associated with their lower mean body temperature and lower resting BMR.


Subject(s)
Basal Metabolism , Body Temperature , Sweating/physiology , Adult , Africa , Humans , Male , Republic of Korea , Young Adult
16.
Chin J Physiol ; 60(5): 301-306, 2017 Oct 31.
Article in English | MEDLINE | ID: mdl-28950696

ABSTRACT

The sweating response is modulated in two different ways depending on adaptation conditions. In this work, we examined sudomotor activities before and after intensive and repetitive heat exposure. Nine male volunteers were exposed to 30-min half-body immersion in hot water (42 ± 0.5°C) at the same time of day on alternate days for 3 weeks. All experiments were performed in an automated climate chamber. Tympanic (Tty) and skin (Ts) temperatures were measured. Mean body temperature (mTb) was calculated. Sudomotor activities, including sweat onset time, sweat rate and volume, activated sweat gland density (ASGD) and output (ASGO), were tested in four regions of the skin: chest, abdomen, upper back and thigh. Basal Tty and mTb were found to decrease by 0.15°C (P < 0.05) and 0.16°C (P < 0.05), respectively. As a typical data (upper back), sweat onset time increased by 33.6% (P < 0.05) after heat acclimation. After heat acclimation, sweat rate decreased by 14.7% (P < 0.05), sweat volume decreased by 15.5% (P < 0.05) and ASGO also decreased by 11.1% (P < 0.05). ASGD decreased by 4.1% after heat acclimation without statistical significance. The data suggest that intensive and repetitive heat exposure induces suppression of sudomotor activities within 3 weeks.


Subject(s)
Hot Temperature , Sweating/physiology , Acclimatization , Adult , Humans , Male
17.
Korean J Physiol Pharmacol ; 20(5): 499-505, 2016 Sep.
Article in English | MEDLINE | ID: mdl-27610036

ABSTRACT

The quantitative sudomotor axon reflex testing (QSART) is a classic test of routine postganglionic sudomotor function. We investigated sudomotor function by QSART after summer (July 2012) and winter (January 2013) seasonal acclimation (SA) in the Republic of Korea. QSART with acetylcholine (ACh) iontophoresis were performed to determine directly activated (DIR) and axon reflex-mediated (AXR1, 2) sweating rate. Onset time of axon reflex, activated sweat gland density (ASGD), activated sweat gland output (ASGO), tympanic and skin temperatures (Tty, Tsk), basal metabolic rate (BMR), and evaporative loss volume changes were measured. Tympanic and mean body temperature (Tb; calculated from Tty, Tsk) were significantly lower after summer-SA than that of winter-SA. Sweat onset time was delayed during winter-SA compared to that after summer-SA. BMR, AXR(1), AXR(2), and DIR sweat rates, ASGD and ASGO, and evaporative loss volume were significantly diminished after winter-SA relative to after summer-SA. In conclusion, changes in sweating activity measured by QSART confirmed the involvement of the peripheral nervous system in variation of sudomotor activity in seasonal acclimation.

18.
Curr Probl Dermatol ; 51: 109-19, 2016.
Article in English | MEDLINE | ID: mdl-27584970

ABSTRACT

The sudomotor mechanism, wich contributes to tolerating thermal environments, is affected by not only the body temperature, but also sex, ethnicity, exercise training, region, season, and heat adaptation. Aging attenuates the sudomotor function by the decreased peripheral sensitivity to acetylcholine and demyelination of innervating nerves. Women show less sudomotor activity than men. Heat adaptation with sudomotor modification is induced by repetitive physical and/or thermal training. Short-term heat acclimation increases sweat gland activity. Long-term heat acclimation results in a reduction in the sweating response to stimuli. Residents of tropical areas sweat less and more slowly than residents of temperate areas. Short-term heat acclimation enhances the sweating response. Long-term heat acclimation, from seasonal change or migration, diminishes the sweating response. Also, deacclimation can be induced by migration from a tropical area to a temperate area. Body composition, especially brown adipose tissue, and weight affect thermal responses. Further studies should investigate BAT and endocrinal pyrogens as additional factors.


Subject(s)
Acclimatization , Aging/physiology , Body Temperature Regulation/physiology , Climate , Sex Characteristics , Sweat Glands/physiology , Sweating/physiology , Adipose Tissue, Brown/physiology , Body Composition/physiology , Ethnicity , Female , Humans , Male
19.
J Sport Health Sci ; 5(4): 443-447, 2016 Dec.
Article in English | MEDLINE | ID: mdl-30356565

ABSTRACT

BACKGROUND: Relatively few studies on the peripheral sweating mechanisms of trained tennis athletes have been conducted. The purpose of this study was to compare the sweating capacities of tennis athletes against untrained subjects (controls). METHODS: Thirty-five healthy male volunteers participated including 15 untrained subjects and 20 trained tennis athletes (nationally ranked). Active heat generation was performed for 30 min (running at 60% VO 2 max ) in a climate chamber (temperature, 25.0°C ± 0.5°C; relative humidity, 60% ± 3%, termed active heating). Sweating data (local sweat onset time, local sweat volume, activated sweat glands, sweat output per gland, whole body sweat loss volume) were measured by the capacitance hygrometer-ventilated capsule method and starch-iodide paper. Mean body temperature was calculated from tympanic and skin temperatures. RESULTS: Local sweat onset time was shorter for tennis athletes (p < 0.001). Local sweat volume, activated sweat glands of the torso and limbs, sweat output per gland, and whole body sweat loss volume were significantly higher for tennis athletes than control subjects after active heating (p < 0.001). Tympanic and mean body temperatures were lower among tennis athletes than controls (p < 0.05). CONCLUSION: These results indicate that tennis athletes had increased regulatory capacity of their sweat gland function.

20.
Korean J Physiol Pharmacol ; 19(1): 9-14, 2015 Jan.
Article in English | MEDLINE | ID: mdl-25605991

ABSTRACT

We investigated the sweating response during passive heating (partial submersion up to the umbilical line in 42±0.5℃ water, 30 min) after summer and winter seasonal acclimatization (SA). Testing was performed in July during the summer, 2011 [summer-SA; temp, 25.6±1.8℃; relative humidity (RH), 82.1±8.2%] and in January during the winter, 2012 (winter-SA; temp, -2.7±2.9℃; RH, 65.0±13.1%) in Cheonan (126°52'N, 33.38'E), Republic of Korea. All experiments were carried out in an automated climatic chamber (temp, 25.0±0.5℃: RH, 60.0±3.0%). Fifteen healthy men (age, 23.4±2.5 years; height, 175.0±5.9 cm; weight, 65.3±6.1 kg) participated in the study. Local sweat onset time was delayed during winter-SA compared to that after summer-SA (p< 0.001). Local sweat volume, whole body sweat volume, and evaporative loss volume decreased significantly after winter-SA compared to those after summer-SA (p<0.001). Changes in basal metabolic rate increased significantly after winter-SA (p< 0.001), and tympanic temperature and mean body temperature were significantly lower after summer-SA (p<0.05). In conclusion, central sudomotor acitivity becomes sensitive to summer-SA and blunt to winter-SA in Rebubic of Korea. These results suggest that the body adjusts its temperature by economically controlling the sweating rate but does not lower the thermal dissipation rate through a more effective evaporation scheme after summer-SA than that after winter-SA.

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