Cooling Strategies for Hyperthermia in the Elderly

Overseen By Erin Harper, BS

Age: 65+

Sex: Any

Trial Phase: Academic

Sponsor: University of Texas Southwestern Medical Center

Disqualifiers: Heart disease, Cancer, Diabetes, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 8

100 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial aims to determine which cooling methods benefit elderly people the most during heat waves. Participants will try various ways to stay cool, such as using a fan, spraying water, or combining these methods. The goal is to assess how these methods reduce heart stress during extremely hot and dry or hot and humid conditions. The trial seeks participants aged 65 and older who do not have major health issues like heart disease or diabetes. As an unphased trial, it offers participants the chance to contribute to important research that could enhance heat wave safety for seniors.

Will I have to stop taking my current medications?

The trial does not specify if you need to stop taking your current medications, but it excludes people with chronic conditions that require regular medication.

What prior data suggests that these cooling strategies are safe for the elderly?

Research shows that using a fan in hot weather can sometimes strain the heart, especially when temperatures exceed 35°C (95°F). Studies suggest fans might not work well in extreme heat. Spraying water on the skin can effectively cool older adults in very hot and dry conditions, as wetting the skin aids cooling. Combining a fan with water spray can enhance this cooling effect. However, in excessive heat, these methods might lose effectiveness. While generally safe, their effectiveness and safety depend on the specific conditions. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about these cooling strategies for hyperthermia in the elderly because they explore simple yet potentially powerful methods that could be more accessible and effective than current options like medication or advanced cooling devices. Unlike standard cooling techniques, such as air conditioning, these methods—using fans, skin cooling, water spray, and combinations—could offer quicker relief and be more practical during heat waves, especially in settings without electricity. By testing these methods in conditions mimicking real-life heat waves, researchers hope to find out which combination or technique works best, offering a practical solution to protect vulnerable populations during extreme heat events.

What evidence suggests that this trial's cooling strategies could be effective for reducing cardiovascular stress in the elderly during heat waves?

This trial will evaluate different cooling strategies for hyperthermia in the elderly. Research has shown that cooling methods like fans and wetting the skin can reduce heat stress in older adults. Participants will experience different cooling modalities in two separate arms. In the "Hot and Humid" arm, participants will face hot and humid conditions, testing methods such as using a fan, skin wetting, or a combination of both. Studies have found that using a fan, especially with skin wetting, can ease heart strain during such weather. For instance, one study found that using a fan with skin wetting reduced heart stress in hot conditions. In the "Very Hot and Dry" arm, participants will encounter very hot and dry conditions, where spraying water on the skin alone can lower body temperature and heart rate. Combining water spray with a fan might be even more effective, as the water cools the skin and the fan helps it evaporate, enhancing the cooling effect. These strategies can be helpful for older adults during heat waves. ^{2 6 7 8 9}

Are You a Good Fit for This Trial?

This trial is for people aged 65 or older who are generally healthy, without significant medical issues based on a thorough check-up. It's not open to those with certain heart problems, a BMI of 31 or higher, chronic conditions needing ongoing treatment, known heart disease, current smokers or those who quit within the last three years.

Inclusion Criteria

I am 65 years old or older.

Free of any significant underlying medical problems based upon a detailed medical history and physical exam

Exclusion Criteria

My heart screening showed possible signs of blocked blood flow or a new heart condition.

Current smokers, as well as individuals who regularly smoked within the past 3 years

My BMI is 31 or higher.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment - Hot and Humid

Participants are exposed to a hot and humid climate chamber for 3 hours with different cooling modalities applied across four visits.

4 visits

4 visits (in-person)

Treatment - Very Hot and Dry

Participants are exposed to a very hot and dry climate chamber for 3 hours with different cooling modalities applied across four visits.

4 visits

4 visits (in-person)

Follow-up

Participants are monitored for safety and effectiveness after treatment, including evaluation of cardiovascular and thermal responses.

2-4 weeks

What Are the Treatments Tested in This Trial?

Interventions

• Control
• Fan
• Skin Cooling, Fan, or Combination of Skin Cooling and Fan
• Water Spray
• Water Spray and Fan

Trial Overview The study is looking at how different cooling methods like fans and water sprays can help reduce heat-related cardiovascular stress in elderly individuals during heat waves. Some participants will use just a fan, others just a spray, some both together, and there'll be a control group with no intervention.

How Is the Trial Designed?

Group I: Very hot and dry Experimental Treatment 4 Interventions

Subjects will be exposed to 3 hours in a climate chamber set to approximately 47 deg C and 15% relative humidity, which reflects a very hot and dry heat wave condition similar to the 2018 Los Angeles heat wave. Four visits will be required to complete this arm, with each visit a different cooling modality applied.

Group II: Hot and humid Experimental Treatment 4 Interventions

Subjects will be exposed to 3 hours in a climate chamber set to approximately 41 deg C and 40% relative humidity, which reflects hot and humid heat wave similar to the 1995 Chicago heat wave. Four visits will be required to complete this arm, with each visit a different cooling modality applied.

Who Is Running the Clinical Trial?

University of Texas Southwestern Medical Center

Lead Sponsor

Trials

1,102

Recruited

1,077,000+

Published Research Related to This Trial

Rapid cooling is crucial for managing heat-stroke, as prolonged hyperpyrexia can lead to poor patient outcomes.

Evaporative cooling has been identified as the most efficient method for cooling, supported by both military and civilian experiences, and should be prioritized in treatment protocols.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Heat-stroke: a review of rapid cooling techniques. Harker, J., Gibson, P.[2019]

The tarp-assisted cooling with oscillation (TACO) method is the only alternative cooling strategy that provides an effective core body temperature cooling rate (0.14-0.17°C/min) for treating exertional heat stroke (EHS) when cold-water immersion (CWI) is not feasible.

Other methods like hand cooling, cold-water showers, and ice-sheet cooling have significantly lower cooling rates (0.03-0.08°C/min) and should not be used if better options are available, emphasizing the importance of using CWI whenever possible.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Do Alternative Cooling Methods Have Effective Cooling Rates for Hyperthermia Compared With Previously Established CWI Cooling Rates? Parker, KC., Shelton, RR., Lopez, RM.[2021]

Rapid cooling is crucial for treating heat stroke, as the prognosis depends on the severity and duration of hyperthermia; immediate cooling methods should be initiated as soon as a patient collapses.

Effective cooling techniques include immersion in ice water (1-5 degrees C) or evaporative cooling, which should be tailored to the patient's age and medical history, ensuring both efficacy and safety.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Heat stroke : a review of cooling methods. Hadad, E., Rav-Acha, M., Heled, Y., et al.[2018]

In a study involving 18 participants (9 young adults and 9 aged adults) exposed to extreme heat and humidity, using an electric fan increased physiological strain in older adults, leading to higher heart rates and core temperatures compared to when no fan was used.

Conversely, young adults experienced a slight reduction in heart rate and only minor changes in core and skin temperatures with fan use, suggesting that fans may not provide the same cooling benefits for older individuals in extreme conditions.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Age Modulates Physiological Responses during Fan Use under Extreme Heat and Humidity. Gagnon, D., Romero, SA., Cramer, MN., et al.[2020]

Infants, children, and adolescents are particularly vulnerable to heat-related illnesses, and the risk increases with prolonged elevated core temperatures, making rapid cooling essential to prevent serious health consequences.

Effective cooling methods include conduction (like ice-water immersion) and convection (using moisture and moving air), with recommendations provided for best practices in treating heat illness, especially for at-risk groups such as obese children or those with special needs.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Pediatric heat-related illness: recommendations for prevention and management Dunn, RJ., Kim, TY.[2019]

In a study with 9 human volunteers, face fanning during heat exposure effectively lowered brain temperature by maintaining a tympanic temperature that was 0.57 degrees Celsius cooler than esophageal temperature, suggesting a protective effect on the brain.

The results indicate that external head cooling methods, like face fanning, can enhance brain cooling and improve comfort during heat stress, potentially offering a strategy for protecting the brain during therapeutic hyperthermia.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Enhanced brain protection during passive hyperthermia in humans. Brinnel, H., Nagasaka, T., Cabanac, M.[2022]

Wearing a water-soaked t-shirt significantly reduces core temperature and thermal strain in older individuals exposed to hot and humid conditions, compared to wearing a dry t-shirt.

Using an electric fan with the water-soaked t-shirt increases sweat losses without providing additional benefits for heat management, making the combination less effective than just the wet t-shirt alone.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Keeping older individuals cool in hot and moderately humid conditions: wetted clothing with and without an electric fan. Cramer, MN., Huang, M., Moralez, G., et al.[2021]

In a study of heat stroke patients in Japan, active cooling combined with rehydration significantly reduced in-hospital mortality rates in severe cases (21.5% mortality) compared to rehydration-only therapy (35.5% mortality).

For patients with mild-to-moderate heat illness, active cooling did not show a significant benefit over rehydration alone, suggesting that cooling is particularly important for those with severe symptoms.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Association between active cooling and lower mortality among patients with heat stroke and heat exhaustion. Kanda, J., Nakahara, S., Nakamura, S., et al.[2023]

In two cases of drug-induced hyperthermia, ice water submersion demonstrated rapid cooling rates, with core temperatures dropping significantly: from 41.4°C to 38°C in 18 minutes and from 44.4°C to 38.8°C in 20 minutes.

These results suggest that ice water submersion may be more effective than mist and fan techniques for quickly reducing body temperature in hyperthermic patients, highlighting the need for further clinical data to determine the best cooling methods.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Ice water submersion for rapid cooling in severe drug-induced hyperthermia. Laskowski, LK., Landry, A., Vassallo, SU., et al.[2018]

Citations

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Effects of pedestal-mounted electric fans on self-reported ... Recent evidence from modelling and laboratory-based studies showed that electric fans are ineffective at meaningfully lowering core temperature in older ...

2. agsjournals.onlinelibrary.wiley.com agsjournals.onlinelibrary.wiley.com/doi/10.1111/jgs.70109

Effect of Ceiling Fans on Core Temperature in Bed‐Resting ... A ceiling fan reduced peak core temperature and other indicators of thermal and cardiovascular strain in bed-resting older adults exposed for 8 ...

3. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC12181687/

Effect of pedestal fan use on serum stress biomarkers in older ... We have shown that electric fan use had nominal impact on reducing body core temperature and cardiovascular strain during daylong exposure to simulated indoor ...

4. sciencedirect.com sciencedirect.com/science/article/pii/S2542519624000305

A critical review of the effectiveness of electric fans as ... Laboratory-based studies have reported that fan use elicited a clinically meaningful improvement in thermal comfort without a meaningful reduction in core ...

5. news-medical.net news-medical.net/news/20241106/Electric-fans-ease-heart-strain-for-older-adults-in-humid-heat.aspx

Electric fans ease heart strain for older adults in humid heat The team found that in hot and humid conditions, fan use with and without skin wetting reduced heat-induced cardiac strain in older people.

6. sciencedirect.com sciencedirect.com/science/article/pii/S0360132325007413

Examining the physiological strain with electric fans during ... We do, however, recommend that the safe indoor temperature threshold for fan use should be less than 45°C as rises in cardiovascular strain, a ...

7. thelancet.com thelancet.com/journals/lanplh/article/PIIS2542-5196(24)00030-5/fulltext

A critical review of the effectiveness of electric fans as ... Health agencies should continue to advise against fan use in air temperatures higher than 35°C, especially for people with compromised sweating capacity (eg, ...

8. jamanetwork.com jamanetwork.com/journals/jamanetworkopen/fullarticle/2837486

Electric Fan Use With Dehydration in Extreme Heat and ... In this study, fan use worsened cardiovascular strain during a 3-hour hot-humid heat exposure with dehydration, but no effect of fan use was ...

9. science.org science.org/content/article/when-is-it-too-hot-use-fan

When is it too hot to use a fan? The US Centers for Disease Control and Prevention (CDC) recommends not using a fan at temperatures above 32.2°C.