An interventional study of Heat therapy and Thermoneutral water immersion in Aging, sponsored by Douglas Seals. Completed at 1 site in United States. Open to participants aged 55 Years to 79 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2021-10-28.
Sponsored by Douglas Seals · Not applicable, Interventional, and Basic science
This study aims to determine the effects of 8-10 weeks of repeated hot water immersion ("heat therapy") vs. thermoneutral water immersion on vascular function in late middle-aged to older (55-79 years) adults.
Advancing age is the primary risk factor for cardiovascular diseases (CVD), which remain the leading cause of death in the developed world. The key process that links aging to increased risk of CVD is the development of arterial dysfunction, including impaired endothelial function and arterial stiffening. In addition, age-associated impairments in arterial function have been linked to other diseases/disorders of aging, including cognitive impairments, Alzheimer's disease and dementia, and motor disorders/disability.
Passive heat therapy, in the form of repeated use of hot baths and saunas, has been used by several cultures for centuries; however, the physiological benefits are only now being elucidated. For example, recent studies have found that lifelong habitual sauna use is associated with considerably reduced risk of all-cause mortality, sudden cardiac death, CVD-related death, and Alzheimer's disease and dementia. In addition, 8-10 weeks of hot water immersion in young adults has been shown to improve endothelial function and reduces arterial stiffness and blood pressure. Therefore, the investigators expect heat therapy to similarly improve vascular function, as well as cognitive and motor function, in middle-aged to older adults who are at greater risk of CVD and related diseases/disorders.
Douglas Seals is the lead sponsor of 3 studies on the registry; none are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Periods have stopped for good: usually no period for 12 months in a row without another medical reason, sometimes confirmed by a blood test (FSH).
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
Short tests of memory and thinking, each scored out of 30. Lower scores suggest more difficulty; criteria give a range, either to include people with memory problems or to leave them out.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
The American Psychiatric Association’s manual of mental health diagnoses. DSM-5 (2013, revised as DSM-5-TR in 2022) replaced DSM-IV, and some studies still name the older edition. “Meets DSM criteria for …” means diagnosed by that edition’s diagnostic criteria, usually by a clinician in an interview.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Postmenopausal
Periods have stopped for good: usually no period for 12 months in a row without another medical reason, sometimes confirmed by a blood test (FSH).
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
GFR and eGFR (kidney filtering)
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
MMSE and MoCA
Short tests of memory and thinking, each scored out of 30. Lower scores suggest more difficulty; criteria give a range, either to include people with memory problems or to leave them out.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
DSM diagnostic criteria
The American Psychiatric Association’s manual of mental health diagnoses. DSM-5 (2013, revised as DSM-5-TR in 2022) replaced DSM-IV, and some studies still name the older edition. “Meets DSM criteria for …” means diagnosed by that edition’s diagnostic criteria, usually by a clinician in an interview.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hot water immersion 3-4x per week for 8-10 weeks
Behavioral: Heat therapy
Thermoneutral water immersion 3-4x per week for 8-10 weeks
Behavioral: Thermoneutral water immersion
30 sessions (3-4x per week for 8-10 weeks) of hot water immersion in 40°C water, sufficient to raise body core temperature to 38.5°C.
30 sessions (3-4x per week for 8-10 weeks) of hot water immersion in 36°C water to prevent changes in body core temperature \>0.2°C.
Brachial artery flow-mediated dilation
Measure of endothelial function
Time frame: 0 and 8 weeks
Carotid-femoral pulse wave velocity
Measure of central arterial stiffness
Time frame: 0 and 8 weeks
Mean arterial blood pressure
Brachial artery blood pressure, measured in triplicate (and averaged) following 20 min of supine rest
Time frame: 0 and 8 weeks
Cerebrovascular reactivity
Measure of cerebral vascular function; magnitude of increase in blood flow through the middle cerebral artery in response to breathing 5% CO2
Time frame: 0 and 8 weeks
Fluid cognition composite score
Multiple domains of cognitive function (incl. executive function, memory, processing speed) assessed using the NIH toolbox (aggregated into one reported value)
Time frame: 0 and 8 weeks
Motor function composite score
Multiple domains of motor function (incl. endurance, strength, dexterity) assessed using the NIH toolbox (aggregated into one reported value)
Time frame: 0 and 8 weeks
Plan to share: No
Ran from Oct 2017 to primary completion in Nov 2020, 36 months.
How these figures are worked out, and which studies are left out of them.
This study is completed, as verified in Oct 2021. You cannot join it, but the record below documents what was studied.
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