scholarly journals Keeping older individuals cool in hot and moderately humid conditions: wetted clothing with and without an electric fan

2020 ◽  
Vol 128 (3) ◽  
pp. 604-611
Author(s):  
Matthew N. Cramer ◽  
Mu Huang ◽  
Gilbert Moralez ◽  
Craig G. Crandall
Keyword(s):  
Heart Rate ◽  
Management Strategy ◽  
Heat Waves ◽  
Tap Water ◽  
Thermal Strain ◽  
Heat Strain ◽  
Older Individuals ◽  
Heat Management ◽  
Mass Losses ◽  
Effective Heat

The present study evaluated whether wearing a water-soaked t-shirt, with or without electric fan use, mitigates thermal and cardiovascular strain in older individuals exposed to hot and moderately humid conditions. Nine healthy older individuals (68 ± 4 yr; five women) completed three 120-min heat exposures (42.4 ± 0.2°C, 34.2 ± 0.9% relative humidity) on separate days while wearing a dry t-shirt (CON), a t-shirt soaked with 500 ml of tap water (WET), or a t-shirt soaked with 500 ml of tap water while facing an electric fan (2.4 ± 0.4 m/s; WET+FAN). Measurements included core and skin temperatures, evaporative mass losses, heart rate, and blood pressure. In the WET condition, elevations in core temperature were attenuated compared with DRY from 30 to 120 min and compared with WET+FAN from 30 to 90 min ( P < 0.05). Evaporative mass losses (inclusive of sweat and water losses from the shirt) were greatest in WET+FAN, followed by WET, and then DRY ( P < 0.01). Sweat losses were lowest in WET, followed by DRY, and then WET+FAN ( P < 0.01). Heart rate was lower only at 60 min in WET versus DRY ( P = 0.01). No differences in mean arterial pressure were observed ( P = 0.51). In conclusion, wearing a water-soaked t-shirt without, but not with, electric fan use is an effective heat management strategy to mitigate thermal strain and lower sweat losses in older individuals exposed to hot and moderately humid conditions. NEW & NOTEWORTHY In older individuals exposed to hot and moderately humid environments, electric fan use coupled with a water-soaked t-shirt exacerbates sweat losses without mitigating heat strain compared with a dry t-shirt. However, wearing a water-soaked t-shirt without fan use reduces sweat losses and attenuates heat strain compared with a dry t-shirt and a fan/water-soaked t-shirt combination. These findings suggest wearing a water-soaked t-shirt is an effective heat-management strategy for older individuals during heat waves when air conditioning is inaccessible.

Do older adults experience greater thermal strain during heat waves?

2014 ◽  
Vol 39 (3) ◽  
pp. 292-298 ◽  
Author(s):  
Jill M. Stapleton ◽  
Joanie Larose ◽  
Christina Simpson ◽  
Andreas D. Flouris ◽  
Ronald J. Sigal ◽  
...  
Keyword(s):  
Older Adults ◽  
Heat Loss ◽  
Heat Waves ◽  
Thermal Strain ◽  
Heat Content ◽  
Whole Body ◽  
Evaporative Heat Loss ◽  
Older Individuals ◽  
Dry Heat ◽  
Body Heat

Heat waves are the cause of many preventable deaths around the world, especially among older adults and in countries with more temperate climates. In the present study, we examined the effects of age on whole-body heat loss and heat storage during passive exposure to environmental conditions representative of the upper temperature extremes experienced in Canada. Direct and indirect calorimetry measured whole-body evaporative heat loss and dry heat exchange, as well as the change in body heat content. Twelve younger (21 ± 3 years) and 12 older (65 ± 5 years) adults with similar body weight (younger: 72.0 ± 4.4 kg; older: 80.1 ± 4.2 kg) and body surface area (younger: 1.8 ± 0.1 m2; older: 2.0 ± 0.1 m2) rested for 2 h in a hot–dry [36.5 °C, 20% relative humidity (RH)] or hot–humid (36.5 °C, 60% RH) environment. In both conditions, evaporative heat loss was not significantly different between groups (dry: p = 0.758; humid: p = 0.814). However, the rate of dry heat gain was significantly greater (by approx. 10 W) for older adults relative to younger adults during the hot–dry (p = 0.032) and hot–humid exposure (p = 0.019). Consequently, the cumulative change in body heat content after 2 h of rest was significantly greater in older adults in the hot–dry (older: 212 ± 25 kJ; younger: 131 ± 27 kJ, p = 0.018) as well as the hot–humid condition (older: 426 ± 37 kJ; younger: 317 ± 45 kJ, p = 0.037). These findings demonstrate that older individuals store more heat during short exposures to dry and humid heat, suggesting that they may experience increased levels of thermal strain in such conditions than people of younger age.

scholarly journals Heat Perception and Coping Strategies: A Structured Interview-Based Study of Elderly People in Cologne, Germany

2021 ◽  
Vol 18 (14) ◽  
pp. 7495
Author(s):  
Juliane Kemen ◽  
Silvia Schäffer-Gemein ◽  
Johanna Grünewald ◽  
Thomas Kistemann
Keyword(s):  
Health Status ◽  
Coping Strategies ◽  
Elderly People ◽  
Heat Waves ◽  
Action Plan ◽  
Heat Strain ◽  
Action Plans ◽  
Health Action ◽  
Heat Perception ◽  
And Coping

The transdisciplinary project “Heat-Health Action Plan for Elderly People in Cologne” addresses the most heat-vulnerable risk group, people over 65 years of age. A quantitative study aimed to better understand heat perception and coping strategies of elderly people during heat waves to inform heat-health action plans. We conducted a representative quantitative survey via structured interviews with 258 randomly chosen people over 65 years old, living in their own homes in four areas of Cologne, Germany. These areas varied, both in terms of social status and heat strain. Data regarding demographics, health status, coping strategies, and heat perception were collected in personal interviews from August to October 2019. The majority of the participants perceived heat strain as moderate to very challenging. Women, people with a lower monthly income, and those with a lower health status found the heat more challenging. We found that participants adapted to heat with a number of body-related, home-protective, and activity-related coping strategies. The number of coping strategies was associated with perceived personal heat strain. There is a definite underuse of water-related heat adaption strategies among the elderly. This is of increasing relevance, as rising heat impact will lead to more heat-related geriatric morbidity. Our results are seminal to inform elderly-specific, socio-adapted local heat-health action plans.

Abstract MP016: Innovation in Exercise: Increasing Capacity of Sedentary Obese Women with Cooling

Circulation ◽  
2012 ◽  
Vol 125 (suppl_10) ◽  
Author(s):  
Stacy T Sims ◽  
Sandra Tsai ◽  
Marcia L Stefanick
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Body Weight ◽  
Waist Circumference ◽  
Body Mass ◽  
Exercise Tolerance ◽  
Thermal Strain ◽  
Walk Test ◽  
Obese Women ◽  
Thermal Discomfort

Background: Barriers to physical activity for obese women include overheating, sweating, fatigue, exhaustion, and rapid heart rate. Adipose tissue acts as a thermal insulator, promoting a greater heat load on the nonfat tissues, reducing heat tolerance; exercise causes a rise in body temperature with an inability to dissipate heat contributing to reduced exercise tolerance. With difficulties of thermoregulation in the sedentary obese population, the aspect of attenuating the discomfort thus associated may encourage continuation of exercise. A heat sink applied to palmar surfaces extracts heat and cools the venous blood, reducing thermal strain by enhancing the volume of cooled venous return. We hypothesized that palmar cooling using a rapid thermal exchange device (RTX) during exercise would attenuate the thermal discomfort of exercise of sedentary obese women, improving exercise tolerance. Methods: To examine whether palmar cooling would impact exercise tolerance in obese women, 24 healthy women aged 30–45 years, with no history of long term structured exercise, a body mass of 120–135% above ideal and/or BMI between 30 and 34.9 were recruited. Women were randomized into a cooling (RXT with 16°C water circulating) or a control (RTX with 37°C water circulating) group and attended 3 exercise sessions a week for 3-months (12 weeks). Each session was comprised of 10 min body weight exercises, 25–45 min treadmill walking at 70–85% HRR with the RTX device, and 10 min of core strengthening exercises. The performance marker was a 1.5 mi walk for time; conducted on the first and last days of the intervention. Mixed models were used to model each of the outcomes as a function of thermal strain, time and treatment with covariates of speed, heart rate, distance, and the interaction of the main effects included in the model. Results: Groups were matched at baseline for key variables (time for 1.5 mile walk test, resting and exercising heart rate [HR], blood pressure [BP], waist circumference [WC], body weight, body mass index [BMI]). Among the cooling group, time to complete the 1.5mile walk test was significantly faster (31.6 ± 2.3 vs. 24.6 ± 2.5 min, pre vs. post, P< 0.01). A greater average exercising HR was observed (136 vs. 154 bpm, pre vs. post, P <0.001), with a significant reduction in WC (41.8 ± 3.1 vs. 39.1 ± 2.2 inches, pre vs. post, P< 0.01) and resting BP (139/84 ± 124/70 mmHg, pre vs. post, P < 0.025). There were no significant differences observed in the control group. Conclusion: Results indicate that exercise tolerance in obese women improved with cooling during exercise, more so than those women who did not have cooling. An improvement in blood pressure, heart rate, waist circumference, and overall aerobic fitness was observed. These findings suggest that by reducing thermal discomfort during exercise, tolerance increases, thus improving cardiovascular parameters of obese women.

Abstract 17288: Risk Prediction of 10-Year Cardiovascular Mortality Using Automated Electrocardiographic Analysis in the National Health and Nutrition Examination Survey

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Amit J Shah ◽  
Cecile Janssens ◽  
Suman Kundu ◽  
Emir Veledar ◽  
Peter Wilson ◽  
...  
Keyword(s):  
Heart Rate ◽  
Risk Prediction ◽  
Risk Score ◽  
Qt Interval ◽  
Validation Cohort ◽  
Risk Scores ◽  
Older Individuals ◽  
Traditional Risk Factors ◽  
Ecg Score ◽  
Cvd Mortality

Introduction: Several individual ECG parameters are predictive of cardiovascular disease (CVD) mortality, and when combined in a score, may improve risk prediction. Hypothesis: We hypothesized that an ECG risk score (based on automated measures available on many modern ECG machines) can effectively predict CVD mortality, and augment risk classification when added to traditional risk factors (TRF). Methods: We examined 6786 individuals aged 40-79 years without known CVD in NHANES III (1988-1994) followed 10 years for CVD mortality. Six pre-specified ECG variables (“ECG model”), were evaluated including P, R, T axes, QT interval, QRS width, and heart rate. Three risk scores were developed for variables containing: 1) TRF only, 2) ECG factors (including age, sex, and race), and 3) TRF+ECG combined. Validation was performed using a cohort aged 40-74 years from NHANES I (n=3773), enrolled in 1971-1974. Age stratification was performed with cutoff of 65 years because of increased competing risks in older individuals. Results: During 10 years of follow up, 384 CVD deaths occurred. Frontal QRS-T angle, T-axis, wide QRS interval (cutoff 120 ms), heart rate-corrected QT interval, and heart rate were found to be significant predictors (p<0.05) of CVD death. As per the table, the ECG score had similar performance compared to the TRF score for the subgroup < 65 years of age in the derivation and validation cohorts. The score with combined ECG + TRF had the best performance for those aged < 65 years, and resulted in a net reclassification index of 9% in the validation cohort using cutoffs of 7.5% and 20% for low, intermediate, and high risk categories. In those aged ≥ 65 years, the combined score showed improvement vs. the TRF score in the derivation, but not validation cohort. Conclusion: A risk score based on routinely reported automated ECG variables and TRF predicts risk of 10-year CVD death better than TRF alone in a cohort age < 65 years without known CVD.

All‐in‐one solar interfacial evaporation system with highly effective heat management and water collection

Solar RRL ◽  
2021 ◽  
Author(s):  
Renzhong Deng ◽  
Chaorui Xue ◽  
Qing Chang ◽  
Jinlong Yang ◽  
Shengliang Hu
Keyword(s):  
Heat Management ◽  
Effective Heat ◽  
Highly Effective ◽  
Water Collection

A Field Evaluation of Construction Workers’ Activity, Hydration Status, and Heat Strain in the Extreme Summer Heat of Saudi Arabia

2020 ◽  
Vol 64 (5) ◽  
pp. 522-535 ◽  
Author(s):  
Mohammed Al-Bouwarthan ◽  
Margaret M Quinn ◽  
David Kriebel ◽  
David H Wegman
Keyword(s):  
Heart Rate ◽  
Saudi Arabia ◽  
Heat Stress ◽  
Heat Exposure ◽  
Heat Strain ◽  
Construction Workers ◽  
Hydration Status ◽  
Summer Heat ◽  
Cardiovascular Strain ◽  
Indoor And Outdoor

Abstract Objectives Assess the impact of summer heat exposure (June–September) on residential construction workers in Al-Ahsa, Saudi Arabia by evaluating (i) heart rate (HR) responses, hydration status, and physical workload among workers in indoor and outdoor construction settings, (ii) factors related to physiological responses to work in hot conditions, and (iii) how well wet-bulb globe temperature-based occupational exposure limits (WBGTOELs) predict measures of heat strain. Methods Twenty-three construction workers (plasterers, tilers, and laborers) contributed 260 person-days of monitoring. Workload energy expenditure, HR, fluid intake, and pre- and postshift urine specific gravity (USG) were measured. Indoor and outdoor heat exposures (WBGT) were measured continuously and a WBGTOEL was calculated. The effects of heat exposure and workload on heart rate reserve (HRR), a measure of cardiovascular strain, were examined with linear mixed models. A metric called ‘heat stress exceedance’ (HSE) was constructed to summarize whether the environmental heat exposure (WBGT) exceeded the heat stress exposure limit (WBGTOEL). The sensitivity and specificity of the HSE as a predictor of cardiovascular strain (HRR ≥30%) were determined. Results The WBGTOEL was exceeded frequently, on 63 person-days indoors (44%) and 91(78%) outdoors. High-risk HRR occurred on 26 and 36 person-days indoors and outdoors, respectively. The HSE metric showed higher sensitivity for HRR ≥30% outdoors (89%) than indoors (58%) and greater specificity indoors (59%) than outdoors (27%). Workload intensity was generally moderate, with light intensity work more common outdoors. The ability to self-pace work was associated with a lower frequency of HRR ≥30%. USG concentrations indicated that workers began and ended their shifts dehydrated (USG ≥1.020). Conclusions Construction work where WBGTOEL is commonly exceeded poses health risks. The ability of workers to self-pace may help reduce risks.

scholarly journals Effects of Three Months of Detraining on the Health Profile of Older Women after a Multicomponent Exercise Program

2019 ◽  
Vol 16 (20) ◽  
pp. 3881 ◽  
Author(s):  
Luis Leitão ◽  
Ana Pereira ◽  
Mauro Mazini ◽  
Gabriela Venturini ◽  
Yuri Campos ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Older Women ◽  
Repeated Measures ◽  
Pulmonary Ventilation ◽  
Exercise Program ◽  
Control Group ◽  
Health Profile ◽  
Older Individuals ◽  
Negative Effects

Physical exercise results in very important benefits including preventing disease and promoting the quality of life of older individuals. Common interruptions and training cessation are associated with the loss of total health profile, and specifically cardiorespiratory fitness. Would detraining (DT) promote different effects in the cardiorespiratory and health profiles of trained and sedentary older women? Forty-seven older women were divided into an experimental group (EG) and a control group (CG) (EG: n = 28, 70.3 ± 2.3 years; CG: n = 19, 70.1 ± 5.6 years). Oxygen uptake (VO2) and health profile assessments were conducted after the exercise program and after three months of detraining. The EG followed a nine-month multicomponent exercise program before a three-month detraining period. The CG maintained their normal activities. Repeated measures ANOVA showed significant increases in total heath and VO2 (p < 0.01) profile over a nine-month exercise period in the EG and no significant increases in the CG. DT led to greater negative effects on total cholesterol (4.35%, p < 0.01), triglycerides (3.89%, p < 0.01), glucose (4.96%, p < 0.01), resting heart rate (5.15%, p < 0.01), systolic blood pressure (4.13%, p < 0.01), diastolic blood pressure (3.38%, p < 0.01), the six-minute walk test (7.57%, p < 0.01), Pulmonary Ventilation (VE) (10.16%, p < 0.01), the Respiratory Exchange Ratio (RER) (9.78, p < 0.05), and VO2/heart rate (HR) (16.08%, p < 0.01) in the EG. DT may induce greater declines in total health profile and in VO2, mediated, in part, by the effectiveness of multicomponent training particularly developed for older women.

scholarly journals Heat Stress, Physiological Response, and Heat-Related Symptoms among Thai Sugarcane Workers

2020 ◽  
Vol 17 (17) ◽  
pp. 6363
Author(s):  
Pongsit Boonruksa ◽  
Thatkhwan Maturachon ◽  
Pornpimol Kongtip ◽  
Susan Woskie
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Heat Stress ◽  
Body Temperature ◽  
Health Effects ◽  
Heat Strain ◽  
Control Measures ◽  
Muscle Cramp ◽  
Factory Workers ◽  
Limit Values

Prolonged or intense exposure to heat can lead to a range of health effects. This study investigated heat exposure and heat-related symptoms which sugarcane workers (90 sugarcane cutters and 93 factory workers) experienced during a harvesting season in Thailand. During the hottest month of harvesting season, wet bulb globe temperature was collected in the work environment, and workloads observed, to assess heat stress. Urine samples for dehydration test, blood pressure, heart rate, and body temperature were measured pre- and post-shift to measure heat strain. Fluid intake and heat-related symptoms which subjects had experienced during the harvesting season were gathered via interviews at the end of the season. From the results, sugarcane cutters showed high risk for heat stress and strain, unlike factory workers who had low risk based on the American Conference of Governmental Industrial Hygiene (ACGIH) threshold limit values (TLVs) for heat stress. Dehydration was observed among sugarcane cutters and significant physiological changes including heart rate, body temperature, and systolic blood pressure occurred across the work shift. Significantly more sugarcane cutters reported experiencing heat-related symptoms including weakness/fatigue, heavy sweating, headache, rash, muscle cramp, dry mouth, dizziness, fever, dry/cracking skin, and swelling, compared to sugarcane factory workers. We conclude that the heat stress experienced by sugarcane cutters working in extremely hot environments, with high workloads, is associated with acute health effects. Preventive and control measures for heat stress are needed to reduce the risk of heat strain.

Seven days of hot water heat acclimation does not modulate the change in heart rate variability during passive heat exposure

2020 ◽  
Author(s):  
Philippe Gendron ◽  
Hugo Gravel ◽  
Hadiatou Barry ◽  
Daniel Gagnon
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
High Frequency ◽  
Water Immersion ◽  
Heat Exposure ◽  
Thermal Strain ◽  
Heat Acclimation ◽  
Hot Water ◽  
Frequency Range ◽  
The Mean

We examined if the change in heart rate variability (HRV) during passive heat exposure is modified by hot water heat acclimation (HA). Sixteen healthy adults (28 ± 5 years, 5 females/11 males) underwent heat exposure in a water-perfused suit, pre and post 7 days of HA (60 minutes at rectal temperature ≥38.6°C). During passive heat exposure, heart rate (HR), the standard deviation of NN intervals (SDNN), the square root of the mean squared differences of successive NN intervals (RMSSD) and the power in the high frequency range (HF) were measured. No difference in HR (P=0.22), SDNN (P=0.87), RMSSD (P=0.79) and HF (P=0.23) was observed at baseline. The increase in HR (pre-HA: 43 ± 10, post-HA: 42 ± 9 bpm, P=0.57) and the decrease of SDNN (pre-HA: -54.1 ± 41.0, post-HA: -52.2 ± 36.8 ms, P=0.85), RMSSD (pre-HA: -70.8 ± 49.5, post-HA: -72.7 ± 50.4 ms, P=0.91) and HF (pre-HA: -28.0 ± 14.5, post-HA: -23.2 ± 17.1%, P=0.27) were not different between experimental visits at fixed increases in esophageal temperature. These results suggest that 7 consecutive days of hot water HA does not modify the change in HRV indices during passive heat exposure. Novelty bullets: - It remains unclear if heat acclimation alters the change in heart rate variability that occurs during passive heat exposure. - At matched levels of thermal strain, 7 consecutive days of hot water immersion did not modulate the change in indices of heart rate variability during passive heat exposure.

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