Effects of Hot and Humid Environments on Thermoregulation and Aerobic Endurance Capacity of Laser Sailors

2021 ◽  
Author(s):  
Yi-Xiao Xu ◽  
Bing-Hong Gao ◽  
Yong-Cai Zhao ◽  
Zhi-Jun Meng ◽  
Ran Li
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Temperature Gradient ◽  
Ambient Temperature ◽  
Skin Temperature ◽  
Heat Storage ◽  
Muscle Power ◽  
Endurance Capacity ◽  
Mean Power ◽  
Physiological Strain

Abstract The purpose was to investigate the effects of hot and humid environments on thermoregulation and aerobic endurance capacity of Laser sailors. A randomized cross-over design was applied to this study, in which nine Laser sailors performed the 6 km rowing test (6 km test) in both a warm (ambient temperature: 23±1.4 °C; relative humidity: 60.5±0.7 %; wind speed: 0 km/h; WARM) and hot environment (ambient temperature: 31.8±1.1 °C; relative humidity: 63.5 ± 4.9 %; wind speed: 3.5±0.7 km/h; HOT). The time for completing 6 km test of HOT group was significantly longer than that of WARM group (P=0.0014). Mean power of 3-4 km, 4-5 km and 5-6 km were significant lower in HOT group (P=0.014, P=0.02, P=0.003). Gastrointestinal temperature and skin temperature were significantly higher in HOT group during the 6 km test (P=0.016, P=0.04). Heat storage at 5 min and 15 min of HOT group were significantly higher than that of WARM group (P=0.0036; P=0.0018). Heart rate and physiological strain index of HOT group were significantly higher than that of WARM group during the 6 km test (P=0.01, P<0.01). The increase magnitude of skin temperature was more obvious than the changes of core temperature during exercise in hot and humid environments. The higher skin temperature narrowed the core to skin temperature gradient and skin to ambient temperature gradient, which may result in greater accumulation of heat storage. The greater heat storage led to the lower muscle power output, which contributed to the reduction of the heat production.

scholarly journals Assessment of ambient dust pollution status at selected point sources (residential and commercial) of Mingaladon area, Yangon region, Myanmar

2018 ◽  
Vol 32 (1) ◽  
pp. 60-68 ◽  
Author(s):  
Sai Nyan Lin Tun ◽  
Than Htut Aung ◽  
Aye Sandar Mon ◽  
Pyay Hein Kyaw ◽  
Wattasit Siriwong ◽  
...  
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Ambient Temperature ◽  
Traffic Congestion ◽  
Pm10 Concentration ◽  
Particulate Matters ◽  
Dust Pollution ◽  
Content Type ◽  
Pm2.5 And Pm10 ◽  
Pm2.5 Concentration

Purpose Dust (particulate matters) is very dangerous to our health as it is not visible with our naked eyes. Emissions of dust concentrations in the natural environment can occur mainly by road traffic, constructions and dust generating working environments. The purpose of this paper is to assess the ambient dust pollution status and to find out the association between PM concentrations and other determinant factors such as wind speed, ambient temperature, relative humidity and traffic congestion. Design/methodology/approach A cross-sectional study was conducted for two consecutive months (June and July, 2016) at a residential site (Defence Services Liver Hospital, Mingaladon) and a commercial site (Htouk-kyant Junction, Mingaladon) based on WHO Air Quality Reference Guideline Value (24-hour average). Hourly monitoring of PM2.5 and PM10 concentration and determinant factors such as traffic congestion, wind speed, ambient temperature and relative humidity for 24 hours a day was performed in both study sites. CW-HAT200 handheld particulate matters monitoring device was used to assess PM concentrations, temperature and humidity while traffic congestion was monitored by CCTV cameras. Findings The baseline PM2.5 and PM10 concentrations of Mingaladon area were (28.50±11.49)µg/m3 and (52.69±23.53)µg/m3, means 61.48 percent of PM2.5 concentration and 54.92 percent of PM10 concentration exceeded than the WHO reference value during the study period. PM concentration usually reached a peak during early morning (within 3:00 a.m.-5:00 a.m.) and at night (after 9:00 p.m.). PM2.5 concentration mainly depends on traffic congestion and temperature (adjusted R2=0.286), while PM10 concentration depends on traffic congestion and relative humidity (adjusted R2=0.292). Wind speed played a negative role in both PM2.5 and PM10 concentration with r=−0.228 and r=−0.266. Originality/value The air quality of the study area did not reach the satisfiable condition. The main cause of increased dust pollution in the whole study area was high traffic congestion (R2=0.63 and 0.60 for PM2.5 and PM10 concentration).

A New Approach for Meteorological Variables Prediction at Kuala Lumpur, Malaysia, Using Artificial Neural Networks: Application for Sizing and Maintaining Photovoltaic Systems

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Tamer Khatib ◽  
Azah Mohamed ◽  
M. Mahmoud ◽  
K. Sopian
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Wind Speed ◽  
Relative Humidity ◽  
Solar Energy ◽  
Ambient Temperature ◽  
Meteorological Variables ◽  
Mean Bias Error ◽  
Artificial Neural ◽  
Prediction Approach

This research presents a new meteorological variables prediction approach for Malaysia using artificial neural networks. The developed model predicts four meteorological variables using sun shine ratio, day number, and location coordinates. These meteorological variables are solar energy, ambient temperature, wind speed, and relative humidity. However, three statistical values are used to evaluate the proposed model. These statistical values are mean absolute percentage error (MAPE), mean bias error (MBE), and root mean square error (RMSE). Based on results, the developed model predicts accurately the four meteorological variables. The MAPE, RMSE, and MBE in predicting solar radiation are 1.3%, 5.8 (1.8%), and 0.9 (0.3%), respectively, while the MAPE, RMSE, and MBE values for ambient temperature prediction are 1.3%, 0.4 (1.7%), and 0.1 (0.4%), respectively. In addition, the MAPE, RMSE, and MBE values in relative humidity prediction are 3.2%, 3.2, and 0.2. As for wind speed prediction, it is the worst in accuracy among the predicted variables because the MAPE, RMSE, and MBE values are 28.9%, 0.5 (31.3%), and 0.02 (1.25%). Such a developed model helps in sizing photovoltaic (PV) systems using solar energy and ambient temperature records. Moreover, wind speed and relative humidity records could be used in estimating dust concentration group which leads to dust deposition on a PV system.

scholarly journals Estimacion Del Potencial De Captura De Agua Atmosferica En Guásimas, Sonora

2018 ◽  
Vol 14 (9) ◽  
pp. 68
Author(s):  
Ana Laura Bautista-Olivas ◽  
Fidencio Cruz Bautista
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Ambient Temperature ◽  
Meteorological Station ◽  
Atmospheric Conditions ◽  
Atmospheric Water

This paper focuses on estimating the potential of the atmospheric conditions in the locality of Guásimas Sonora for the capture of atmospheric water. To achieve this goal, an automated meteorological station was installed to record the ambient temperature, relative humidity, wind speed, and precipitation at the study site. According to the results obtained, the potential of the atmospheric conditions for the capture of water in the locality of Guásimas, in general, is medium. It presents a period of 20 to 30 days a year to capture atmospheric water with passive collectors and between 105 and 130 days during the year for the condensation of atmospheric water with active collectors.

Heat strain models applicable for protective clothing systems: comparison of core temperature response

1997 ◽  
Vol 83 (3) ◽  
pp. 1017-1032 ◽  
Author(s):  
R. R. Gonzalez ◽  
T. M. McLellan ◽  
W. R. Withey ◽  
S. K. Chang ◽  
K. B. Pandolf
Keyword(s):  
Heat Stress ◽  
Wind Speed ◽  
Relative Humidity ◽  
Ambient Temperature ◽  
Core Temperature ◽  
Protective Clothing ◽  
Temperature Response ◽  
The United States ◽  
Heat Strain ◽  
Intermittent Work

Gonzalez, R. R., T. M. McLellan, W. R. Withey, S. K. Chang, and K. B. Pandolf. Heat strain models applicable for protective clothing systems: comparison of core temperature response. J. Appl. Physiol. 83(3): 1017–1032, 1997.—Core temperature (Tc) output comparisons were analyzed from thermal models applicable to persons wearing protective clothing. The two models evaluated were the United States (US) Army Research Institute of Environmental Medicine (USARIEM) heat strain experimental model and the United Kingdom (UK) Loughborough (LUT25) model. Data were derived from collaborative heat-acclimation studies conducted by three organizations and included an intermittent-work protocol (Canada) and a continuous-exercise/heat stress protocol (UK and US). Volunteers from the US and the UK were exposed to a standard exercise/heat stress protocol (ambient temperature 35°C/50% relative humidity, wind speed 1 m/s, level treadmill speed 1.34 m/s). Canadian Forces volunteers did an intermittent-work protocol (15 min moderate work/15 min rest at ambient temperature of 40°C/30% relative humidity, wind speed ≈0.4 m/s). Each model reliably predicted Tc responses (within the margin of error determined by 1 root mean square deviation) during work in the heat with protective clothing. Models that are analytically similar to the classic Stolwijk-Hardy model serve as robust operational tools for prediction of physiological heat strain when modified to incorporate clothing heat-exchange factors.

scholarly journals Cubed-ice vs Wetted-ice as a Cryotherapeutic Agent in the Malaysian Climate

2018 ◽  
Vol 3 (11) ◽  
pp. 45
Author(s):  
Norlizah Abdul Hamid ◽  
Mohd Firdaus Nawawi ◽  
Nagoor Meera Abdullah ◽  
Rozita Abd Latif
Keyword(s):  
Open Access ◽  
Relative Humidity ◽  
Ambient Temperature ◽  
Skin Temperature ◽  
Peer Review ◽  
Publishing House ◽  
Paired Sample ◽  
Cutaneous Temperature ◽  
International Publishing ◽  
Open Access Article

The effects of cubed-ice and wetted-ice on cutaneous temperature were studied. Skin temperature was taken at every two-minute intervals, for a period of 20 minutes. 20 female varsity students with mean age of 21.7 ± 0.6 years, mean height of 161.6 ± 5.47 cm, and mean body mass of 54.1 ± 8.8 kg participated in this study. Paired sample t-test showed that cubed-ice was a better cryotherapeutic agent than wetted-ice. The result contradicts the findings of past studies suggesting that ambient temperature and relative humidity could have an effect on the efficacy of the cryotherapeutic agents. Keywords: Malaysia climate; cutaneous temperature;cube ice; wetted-iceeISSN 2398-4295 © 2018. The Authors. Published for AMER ABRA cE-Bs by e-International Publishing House, Ltd., UK. This is an open-access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer–review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians) and cE-Bs (Centre for Environment-Behaviour Studies), Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, Malaysia. 

scholarly journals Effects of Cooling During Exercise on Thermoregulatory Responses of Men With Paraplegia

2016 ◽  
Vol 96 (5) ◽  
pp. 650-658 ◽  
Author(s):  
Coen C.W.G. Bongers ◽  
Thijs M.H. Eijsvogels ◽  
Ilse J.W. van Nes ◽  
Maria T.E. Hopman ◽  
Dick H.J. Thijssen
Keyword(s):  
Body Temperature ◽  
Temperature Gradient ◽  
Ambient Temperature ◽  
Skin Temperature ◽  
Thermal Sensation ◽  
Core Body Temperature ◽  
The Core ◽  
Cord Injury ◽  
Core Body ◽  
Trunk Skin

Background People with spinal cord injury (SCI) have an altered afferent input to the thermoregulatory center, resulting in a reduced efferent response (vasomotor control and sweating capacity) below the level of the lesion. Consequently, core body temperature rises more rapidly during exercise in individuals with SCI compared with people who are able-bodied. Cooling strategies may reduce the thermophysiological strain in SCI. Objective The aim of this study was to examine the effects of a cooling vest on the core body temperature response of people with a thoracic SCI during submaximal exercise. Methods Ten men (mean age=44 years, SD=11) with a thoracic lesion (T4–T5 or below) participated in this randomized crossover study. Participants performed two 45-minute exercise bouts at 50% maximal workload (ambient temperature 25°C), with participants randomized to a group wearing a cooling vest or a group wearing no vest (separate days). Core body temperature and skin temperature were continuously measured, and thermal sensation was assessed every 3 minutes. Results Exercise resulted in an increased core body temperature, skin temperature, and thermal sensation, whereas cooling did not affect core body temperature. The cooling vest effectively decreased skin temperature, increased the core-to-trunk skin temperature gradient, and tended to lower thermal sensation compared with the control condition. Limitations The lack of differences in core body temperature among conditions may be a result of the relative moderate ambient temperature in which the exercise was performed. Conclusions Despite effectively lowering skin temperature and increasing the core-to-trunk skin temperature gradient, there was no impact of the cooling vest on the exercise-induced increase in core body temperature in men with low thoracic SCI.

CATFISH DRYING (Clarias Batraclus) USING ‘TEKO BERSAYAP’ SOLAR DRYER

2012 ◽  
Vol 2 (1) ◽  
pp. 14-20
Author(s):  
Yuwana Yuwana
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Ambient Temperature ◽  
Drying Rate ◽  
Drying Process ◽  
Drying Time ◽  
Ambient Relative Humidity ◽  
Solar Dryer

Experiment on catfish drying employing ‘Teko Bersayap’ solar dryer was conducted. The result of the experiment indicated that the dryer was able to increase ambient temperature up to 44% and decrease ambient relative humidity up to 103%. Fish drying process followed equations : KAu = 74,94 e-0,03t for unsplitted fish and KAb = 79,25 e-0,09t for splitted fish, where KAu = moisture content of unsplitted fish (%), KAb = moisture content of splitted fish (%), t = drying time. Drying of unsplitted fish finished in 43.995 hours while drying of split fish completed in 15.29 hours. Splitting the fish increased 2,877 times drying rate.

scholarly journals A novel mouse model of heatstroke accounting for ambient temperature and relative humidity

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Kazuyuki Miyamoto ◽  
Keisuke Suzuki ◽  
Hirokazu Ohtaki ◽  
Motoyasu Nakamura ◽  
Hiroki Yamaga ◽  
...  
Keyword(s):  
Gene Expression ◽  
Body Temperature ◽  
Relative Humidity ◽  
Ambient Temperature ◽  
Core Body Temperature ◽  
Heat Exposure ◽  
Organ Damage ◽  
Core Body ◽  
The Impact ◽  
Treatment Water

Abstract Background Heatstroke is associated with exposure to high ambient temperature (AT) and relative humidity (RH), and an increased risk of organ damage or death. Previously proposed animal models of heatstroke disregard the impact of RH. Therefore, we aimed to establish and validate an animal model of heatstroke considering RH. To validate our model, we also examined the effect of hydration and investigated gene expression of cotransporter proteins in the intestinal membranes after heat exposure. Methods Mildly dehydrated adult male C57/BL6J mice were subjected to three AT conditions (37 °C, 41 °C, or 43 °C) at RH > 99% and monitored with WetBulb globe temperature (WBGT) for 1 h. The survival rate, body weight, core body temperature, blood parameters, and histologically confirmed tissue damage were evaluated to establish a mouse heatstroke model. Then, the mice received no treatment, water, or oral rehydration solution (ORS) before and after heat exposure; subsequent organ damage was compared using our model. Thereafter, we investigated cotransporter protein gene expressions in the intestinal membranes of mice that received no treatment, water, or ORS. Results The survival rates of mice exposed to ATs of 37 °C, 41 °C, and 43 °C were 100%, 83.3%, and 0%, respectively. From this result, we excluded AT43. Mice in the AT 41 °C group appeared to be more dehydrated than those in the AT 37 °C group. WBGT in the AT 41 °C group was > 44 °C; core body temperature in this group reached 41.3 ± 0.08 °C during heat exposure and decreased to 34.0 ± 0.18 °C, returning to baseline after 8 h which showed a biphasic thermal dysregulation response. The AT 41 °C group presented with greater hepatic, renal, and musculoskeletal damage than did the other groups. The impact of ORS on recovery was greater than that of water or no treatment. The administration of ORS with heat exposure increased cotransporter gene expression in the intestines and reduced heatstroke-related damage. Conclusions We developed a novel mouse heatstroke model that considered AT and RH. We found that ORS administration improved inadequate circulation and reduced tissue injury by increasing cotransporter gene expression in the intestines.

Sign in / Sign up

Export Citation Format

Share Document