This study investigated the differences in heat dissipation response to intense heat stress during exercise in hot and humid environments between tropical and temperate indigenes with matched ...physical characteristics. Ten Japanese (JP) and ten Malaysian (MY) males participated in this study. Subjects performed exercise for 60 min at 55% peak oxygen uptake in 32°C air with 70% relative humidity, followed by 30 min recovery. The increase in rectal temperature (
T
re
) was smaller in MY during exercise compared to JP. The local sweat rate and total body mass loss were similar in both groups. Both skin blood flow and mean skin temperature was lower in MY compared to JP. A significantly greater increase in hand skin temperature was observed in MY during exercise, which is attributable to heat loss due to the greater surface area to mass ratio and large number of arteriovenous anastomoses. Also, the smaller increase in
T
re
in MY may be explained by the presence of a significantly greater core–skin temperature gradient in MY than JP. The thermal gradient is also a major factor in increasing the convective heat transfer from core to skin as well as skin blood flow. It is concluded that the greater core–skin temperature gradient observed in MY is responsible for the smaller increase in
T
re
.
Abstract Previous research suggests that water exercise improves the activities of daily living (ADL) ability of the frail elderly, but the specific frequency and intensity of such programs is ...unclear. This study aims at comparing the effects of once- and twice-weekly water exercise on the ADL ability of frail elderly receiving nursing care for 2 years. The design is a prospective randomized longitudinal study. Participants were assigned to two different exercise groups (Group 1 and Group 2). Group 1 participated in a 60-min exercise session once a week, for 2 years, while Group 2 attended the session twice a week. Exercise sessions were divided into a 10-min warm-up on land and 50 min of exercise in water. The 50-min water exercise program consisted of 20 min walking, 10 min ADL exercise, 10 min stretching and strength exercises, and 10 min relaxation in water. ADL ability and lower muscle strength were measured before the beginning of exercise and 6 months, 1 year, and 2 years after the program had started. Significant group differences occurred for bathing transfer and stair climbing at the 2-year measurement. These results suggested that at least twice-weekly water exercise was necessary to maintain the ADL ability and KEX of the frail elderly during the 1-year water exercise period and for one additional year afterward.
For the coherent understanding of heat acclimatization in tropical natives, we compared ethnic differences between tropical and temperate natives during resting, passive and active heating ...conditions. Experimental protocols included: (1) a resting condition
(
an air temperature of 28°C with 50% RH), (2) a passive heating condition (28°C with 50% RH; leg immersion in a hot tub at a water temperature of 42°C), and (3) an active heating condition (32°C with 70% RH; a bicycle exercise). Morphologically and physically matched tropical natives (ten Malaysian males, MY) and temperate natives (ten Japanese males, JP) participated in all three trials. The results saw that: tropical natives had a higher resting rectal temperature and lower hand and foot temperatures at rest, smaller rise of rectal temperature and greater temperature rise in bodily extremities, and a lower sensation of thirst during passive and active heating than the matched temperate natives. It is suggested that tropical natives’ homeostasis during heating is effectively controlled with the improved stability in internal body temperature and the increased capability of vascular circulation in extremities, with a lower thirst sensation. The enhanced stability of internal body temperature and the extended thermoregulatory capability of vascular circulation in the extremities of tropical natives can be interpreted as an interactive change to accomplish a thermal dynamic equilibrium in hot environments. These heat adaptive traits were explained by Wilder’s law of initial value and Werner’s process and controller adaptation model.
There are several types of cold adaptation based on the alteration of thermoregulatory response. It has been thought that the temperature of repeated cold exposures during the adaptation period is ...one of the factors affecting the type of cold adaptation developed. This study tested the hypothesis that repeated mild cold immersions would induce an insulative cold adaptation but would not alter the metabolic response. Seven healthy male participants were immersed to their xiphoid process level repeatedly in 26°C water for 60 min, 3 days every week, for 4 weeks. During the first and last exposure of this cold acclimation period, the participants underwent body immersion tests measuring their thermoregulatory responses to cold. Separately, they conducted finger immersion into 5°C water for 30 min to assess their cold-induced vasodilation (CIVD) response before and after cold acclimation. During the immersion to xiphoid process, participants showed significantly lower mean skin temperature and skin blood flow in the forearm post-acclimation, while no adaptation was observed in the metabolic response. Additionally, blunted CIVD responses were observed after cold acclimation. From these results, it was considered that the participants showed an insulative-type of cold acclimation after the repeated mild cold immersions. The major finding of this study was the acceptance of the hypothesis that repeated mild cold immersion was sufficient to induce insulative cold adaptation but did not alter the metabolic response. It is suggested that the adaptation in the thermoregulatory response is specific to the response which is repeatedly stimulated during the adaptation process.
In this paper, we investigated the source/drain recessed contact structure to mitigate the self-heating-effects in vertically stacked-nanowire FETs. As a result, lattice temperature of nanowire ...regions during device operation was considerably decreased by using the source/drain recessed contact structure. This is attributed to an increase in heat dissipation mainly from heat source to bulk wafer. Moreover, we proposed the p/n-stacked nanowire on bulk FinFET and its 6T-SRAM layout. Area of the proposed SRAM was reduced approximately 15%, as compared to the conventional cell layout.
Purpose. The purpose of this study was to compare two-year effects of once-weekly and twice-weekly water exercise programmes at a day-service facility on the health-related quality of life (HRQL) of ...frail elderly people.
Method. This single blind, prospective, longitudinal randomized pilot study separated 22 community-dwelling frail elderly people into once-weekly (once group: n = 10) and twice-weekly (twice group: n = 12) groups: the two-year exercise interventions were once- or twice-weekly 1-h sessions. Water exercise sessions comprised warming-up on land, activities of daily living (ADL) exercise, stretching, strength, and relaxation in water. The HRQL was evaluated using the Medical Outcomes Survey Short Form-36 questionnaire (SF-36); ADL dependence was assessed using the Functional Independence Measure (FIM).
Result. Both groups showed significant increases over pre-intervention (pre) scores at 6 months and 12 months on Physical Component Summary and Mental Component Summary. In the once group, both were lower at 24 months than at 6 months and 12 months. The FIM scores were significantly different from pre at 6 months and 12 months in both once and twice groups, and between pre and 24 month in the twice group.
Conclusion. Better than once-weekly exercise, twice-weekly water exercise controlled deterioration of HRQL, ADL, and knee extensor muscle strength (KEX) with ageing.
The purpose of this study was to investigate ethnic differences in cutaneous thermal sensation thresholds and the inter-threshold sensory zone between tropical (Malaysians) and temperate natives ...(Japanese). The results showed that (1) Malaysian males perceived warmth on the forehead at a higher skin temperature (
T
sk) than Japanese males (
p<0.05), whereas cool sensations on the hand and foot were perceived at a lower
T
sk in Malaysians (
p<0.05); (2) Overall, the sensitivity to detect warmth was greater in Japanese than in Malaysian males; (3) The most thermally sensitive body region of Japanese was the forehead for both warming and cooling, while the regional thermal sensitivity of Malaysians had a smaller differential than that of Japanese; (4) The ethnic difference in the inter-threshold sensory zone was particularly noticeable on the forehead (1.9±1.2
C for Japanese, 3.2±1.6
°C for Malaysians,
p<0.05). In conclusion, tropical natives had a tendency to perceive warmth at a higher
T
sk and slower at an identical speed of warming, and had a wider range of the inter-threshold sensory zone than temperate natives.
Abstract Although deep-water running (DWR) is often used to obtain the benefits of aerobic fitness and to reduce vertical component stress, its attendant muscle stress remains unclear. The present ...study investigated lower extremity muscle activity and during DWR compared to that during land walking (LW) and water walking (WW). Surface electromyography was used to evaluate muscle activity in nine healthy adults during each exercise at self-determined slow, moderate, and fast paces. The duration of swing phase, ankle, knee and hip joint angle, and each joint range of motion (ROM) also investigated. Results show that the percentages of maximal voluntary contraction (%MVC) of the soleus and medial gastrocnemius were lower during DWR than during LW or WW in the backward swing phase. The %MVC of the rectus femoris was higher during WW and DWR than during LW; that of the vastus lateralis was lower during WW and DWR than during LW in the forward swing phase. In the biceps femoris, the %MVC was higher during DWR than during LW or WW in the forward and backward swing phase. Every pace showed a similar trend. These results suggest that DWR can stimulate the hip joint flexor or extensor muscles.
The objective of this study was to investigate thermoregulatory responses to heat in tropical (Malaysian) and temperate (Japanese) natives, during 60 min of passive heating. Ten Japanese (mean ages: ...20.8 ± 0.9 years) and ten Malaysian males (mean ages: 22.3 ± 1.6 years) with matched morphological characteristics and physical fitness participated in this study. Passive heating was induced through leg immersion in hot water (42°C) for 60 min under conditions of 28°C air temperature and 50% RH. Local sweat rate on the forehead and thigh were significantly lower in Malaysians during leg immersion, but no significant differences in total sweat rate were observed between Malaysians (86.3 ± 11.8 g m
−2
h
−1
) and Japanese (83.2 ± 6.4 g m
−2
h
−1
) after leg immersion. In addition, Malaysians displayed a smaller rise in rectal temperature (0.3 ± 0.1°C) than Japanese (0.7 ± 0.1°C) during leg immersion, with a greater increase in hand skin temperature. Skin blood flow was significantly lower on the forehead and forearm in Malaysians during leg immersion. No significant different in mean skin temperature during leg immersion was observed between the two groups. These findings indicated that regional differences in body sweating distribution might exist between Malaysians and Japanese during heat exposure, with more uniform distribution of local sweat rate over the whole body among tropical Malaysians. Altogether, Malaysians appear to display enhanced efficiency of thermal sweating and thermoregulatory responses in dissipating heat loss during heat loading. Thermoregulatory differences between tropical and temperate natives in this study can be interpreted as a result of heat adaptations to physiological function.
The purpose of this study was to explore whether there is evidence of heat acclimatization in the words used to express thermal sensation. A total of 458 urban Japanese and 601 Indonesians ...participated in a questionnaire. In addition, in a preliminary survey, 39 native English speakers in the UK participated. Our results showed that (1) for Indonesians, the closest thermal descriptor of a feeling of thermal comfort was ‘cool’ (75%) followed by ‘slightly cool’ (7%), ‘slightly cold’ (5%) and ‘cold’ (5%), while Japanese responses were distributed uniformly among descriptors ‘cool’, ‘slightly cool’, ‘neither’, ‘slightly warm’, and ‘warm’; (2) the closest thermal descriptors of a feeling of discomfort for Indonesians were less affected by individual thermal susceptibility (vulnerability) than those for Japanese; (3) in the cases where ‘cool’ and ‘slightly cold’ were imagined in the mind, the descriptors were cognized as a thermal comfortable feeling by 97% and 57% of Indonesians, respectively; (4) the most frequently voted choice endorsing hot weather was ‘higher than 32°C’ for Indonesians and ‘higher than 29°C’ for Japanese respondents; for cold weather, ‘lower than 15°C’ for Japanese and ‘lower than 20°C’ for Indonesians. In summary, the descriptor ‘cool’ in Indonesians connotes a thermally comfortable feeling, but the inter-zone between hot and cold weather that was judged in the mind showed a upward shift when compared to that of Japanese. It is suggested that linguistic heat acclimatization exists on a cognitive level for Indonesians and is preserved in the words of thermal descriptors.
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