Passive Heating for Aging

Overseen By William E Hughes, Ph.D.

Age: 18+

Sex: Any

Trial Phase: Phase < 1

Sponsor: William Hughes

Must not be taking: Antihypertensives, Statins, Anticoagulants, others

Disqualifiers: Hypertension, Diabetes, Heart failure, others

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

Compensation: Varies

Number of Visits: 1

Duration: 1 session

20 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial tests whether passive heating, such as soaking legs in warm water, can improve blood vessel health in older adults. The researchers aim to determine if this method can enhance blood vessel function, similar to exercise, without requiring physical activity. The trial specifically examines whether passive heating might protect against age-related issues like heart disease. Individuals with a manageable heart health profile who do not smoke or have certain medical conditions may be suitable candidates for this trial. As an Early Phase 1 trial, this research seeks to understand how passive heating affects people, offering participants the opportunity to contribute to groundbreaking health insights.

Will I have to stop taking my current medications?

The trial requires that you do not take certain medications, such as anti-hypertensive drugs, statins, beta blockers, anti-coagulants, and others listed in the exclusion criteria. If you are on any of these medications, you may need to stop taking them to participate.

What prior data suggests that passive heating is safe for humans?

Research has shown that passive heating, such as soaking legs in warm water, is usually safe and well-tolerated by older adults. Studies indicate that middle-aged and older individuals can handle hot water immersion with few issues. While younger adults sometimes experience dizziness, this is less common in older adults.

Passive heating has improved heart health in older people, even those with ongoing health issues, by enhancing heart and blood vessel function. Some studies suggest it might not significantly change other health markers, but it does support heart and blood vessel health.

Since this trial is in the early stages, the safety of the treatment is still under review. However, existing evidence from various studies shows that passive heating is generally safe for older adults. ^{1 2 3 4 5}

Why do researchers think this study treatment might be promising?

Unlike typical treatments for age-related conditions that often rely on medications or physical therapy, passive heating is a non-invasive technique that could offer a unique benefit. The treatment involves immersing the lower limbs in warm water, which may improve blood circulation without the need for exercise or medication. This approach could be particularly beneficial for individuals who have limitations in mobility or those who prefer non-drug interventions. Researchers are excited about the potential of passive heating to enhance vascular health in a simple and accessible way.

What evidence suggests that passive heating might be an effective treatment for aging?

Research has shown that passive heating, such as sitting in warm water, can improve heart and blood vessel health, particularly in older adults. Studies have found that regular warm water immersion helps the body cool down more effectively and reduces stress on the heart, leading to lower blood pressure and better function of large blood vessels. Some early evidence also suggests that passive heating might support autophagy, a cellular recycling process, which could enhance the function of small blood vessels. Overall, passive heating appears promising for improving heart health, especially for those who find exercise challenging. Participants in this trial will experience passive heating by immersing their lower limbs in warm circulating water for 60 minutes. ^{2 3 5 6 7}

Are You a Good Fit for This Trial?

This trial is for older adults interested in improving their blood vessel function, which can help prevent heart disease. Participants should be able to undergo passive heating sessions. Specific eligibility details are not provided, so it's best to contact the study team for more information.

Inclusion Criteria

I have one or no risk factors for heart disease.

Exclusion Criteria

I have high cholesterol and may be taking medication for it.

BMI greater than 30

I have diabetes.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants undergo passive heating therapy with lower limbs immersed in warm circulating water for 60 minutes

1 session

1 visit (in-person)

Follow-up

Participants are monitored for changes in microvascular function and other cardiovascular parameters

1-2 weeks

What Are the Treatments Tested in This Trial?

Interventions

• Passive Heating

Trial Overview The trial is studying how passive heating (raising body temperature by about 1°C) affects small blood vessels and whether it can mimic the beneficial effects of exercise on cardiovascular health in aging individuals without the need for physical activity.

How Is the Trial Designed?

Group I: Passive Heating of lower limbs Experimental Treatment 2 Interventions

The lower limbs will be immersed in warm circulating water for 60 minutes.

Who Is Running the Clinical Trial?

William Hughes

Lead Sponsor

Trials

1

Recruited

20+

Published Research Related to This Trial

In a study comparing six older men (average age 61) and six young men (average age 26) during heat exposure, older individuals showed a lower heart rate during heat acclimation, indicating a potential difference in cardiovascular response to heat stress.

Both age groups benefited from a 9-day heat acclimation, resulting in lower baseline body temperatures during heat exposure, but older men had a reduced ability to increase forearm blood flow and sweating rates compared to younger men, suggesting age-related differences in thermoregulatory function.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effects of age and acclimation on responses to passive heat exposure. Armstrong, CG., Kenney, WL.[2022]

In a study involving nine older female insomniacs, passive body heating through hot baths significantly improved sleep continuity and led to deeper, more restful sleep, indicating its potential as a treatment for insomnia.

The hot baths (40-40.5 degrees C) also delayed the body's temperature drop before sleep, which may contribute to the observed increase in slow-wave sleep (SWS) and overall sleep quality.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effects of passive body heating on the sleep of older female insomniacs. Dorsey, CM., Lukas, SE., Teicher, MH., et al.[2017]

Citations

1. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/39820413/

Short-Term Warm Water Immersion for Improving Whole- ... Conclusions: Seven consecutive days of warm water immersion improved whole-body heat loss and reduced core temperature and cardiovascular strain ...

2. journals.physiology.org journals.physiology.org/doi/full/10.1152/japplphysiol.00701.2023?doi=10.1152/japplphysiol.00701.2023

Passive heat therapy: a promising preventive measure for ... Passive heat therapy improves cardiovascular function and health in middle-aged and older adults living with or without chronic diseases.

3. physoc.onlinelibrary.wiley.com physoc.onlinelibrary.wiley.com/doi/full/10.1113/EP090993

The effect of age and mitigation strategies during hot water ... In response to an orthostatic challenge following passive heating, older adults have been shown to have a greater reduction in cerebral blood ...

4. clinicaltrials.gov clinicaltrials.gov/study/NCT05838612

Hot Water Immersion as a Heat Acclimation Strategy in ... The following study aims to assess the effectiveness of a 7-day warm-water immersion (~40°C) protocol in enhancing whole-body heat loss in older adults.

5. journals.plos.org journals.plos.org/plosone/article?id=10.1371/journal.pone.0282038

Short-term heat acclimation protocols for an aging population Short-term hot water immersion results in substantial thermal strain and partial heat acclimation; comparisons with heat- exercise exposures.

6. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC10103862/

The effect of age and mitigation strategies during hot water ... Hot water immersion was well tolerated by middle‐aged adults, but younger adults suffered from a greater frequency and severity of dizziness.

7. sciencedirect.com sciencedirect.com/science/article/pii/S2666667725001576

Non-acute effects of passive heating interventions on ... Current evidence from RCTs indicates that passive heating interventions may not improve most of the cardiometabolic or vascular health markers.