Passive hot-water immersion to lower systolic blood pressure and improve blood vessel health in middle-aged and older adults

Passive heat therapy for lowering systolic blood pressure and improving vascular function in mid-life and older adults

NIH-funded research University of Colorado · NIH-11337494

This program uses regular hot water immersion to lower systolic blood pressure and improve blood vessel health for people aged 50 and older.

Quick facts

Grant typeR01 grant
Study typeNIH-funded research
Funding institutionUniversity of Colorado NIH-funded
Lab location1 site (Boulder, UNITED STATES)
Project IDNIH-11337494 on NIH RePORTER

What this research studies

You would sit in hot water baths that raise your core temperature to about 38.5–39.0°C for repeated sessions over several weeks. The team plans roughly 30 sessions across about 10 weeks based on prior pilot work. Before and after the program they will measure resting and 24-hour blood pressure, tests of blood vessel function (flow-mediated dilation and pulse wave velocity), and blood markers of oxidative stress and nitric oxide. The approach builds on small pilot studies showing it is generally safe and tolerable in mid-life and older adults.

Who could benefit from this research

Good fit: Ideal candidates are adults aged about 50 and older with resting systolic blood pressure in the elevated (120–129 mmHg) or stage 1 (130–139 mmHg) ranges who can safely tolerate hot water immersion.

Not a fit: People with higher uncontrolled hypertension, unstable heart conditions, inability to tolerate heat, or specific medical contraindications may not receive benefit and could be harmed.

Why it matters

Potential benefit: If successful, this could lower systolic blood pressure by several mmHg and improve vascular function, offering a non-drug option to reduce cardiovascular risk.

How similar studies have performed: Small studies in young adults and a pilot trial in mid-life/older adults (n=23) reported safety and improvements in blood pressure and vascular measures, but larger trials are needed.

Where this research is happening

Boulder, UNITED STATES

Researchers

About this research

  1. This is an active NIH-funded research project — typically early-stage science, not a clinical trial accepting patient enrollment.
  2. Some NIH-funded labs run parallel clinical studies or seek volunteers for related work. To check, contact the principal investigator or institution listed above.
  3. For full project details, budget, and progress reports, visit the official NIH RePORTER page below.
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.