Trial Outcomes & Findings for Heat Therapy Versus Exercise Training in Hypertension (NCT NCT03557502)

NCT ID: NCT03557502

Last Updated: 2025-06-04

Results Overview

Ambulatory blood pressure (ABP) was measured at baseline (PRE) and after 30 heat therapy or exercise training sessions (POST) over the course of 8-10 weeks. Two individuals performed post-intervention testing after completing only 27 sessions (1 in each group). Participants arrived at the lab and were fitted with an oscillometric blood pressure cuff attached to an ambulatory blood pressure monitor. The monitor was programmed to inflate and assess blood pressure every 20 min during self-reported waking hours and every 60 min during self-reported sleeping hours. Waking and sleeping times and measurement frequency were replicated at POST within each participant. Ambulatory blood pressure data were analyzed as 24-h total for both systolic and diastolic blood pressure. Change was calculated as the value at the POST timepoint minus the value at the PRE timepoint.

Recruitment status

COMPLETED

Study phase

NA

Target enrollment

44 participants

Primary outcome timeframe

10 weeks

Results posted on

2025-06-04

Participant Flow

Three enrollees declined to participate after being registered for the clinical trial (assigned a participant number) but before initiating the intervention.

Protocol 2 participants consisted of a subset of participants from Protocol 1 (i.e. Participants were only eligible for Protocol 2 if they participated in Protocol 1). Not all participants who participated in Protocol 1 were qualified or interested to participate in Protocol 2.

Participant milestones

Participant milestones
Measure
Heat Therapy Group
Group will undergo 30 sessions of heat therapy over approximately 10 weeks. Sessions will require subjects to be immersed in hot water for up to 45 minutes per session. Heat Therapy Group: 30 sessions of immersion in 40.5 degree celsius water for 45 minutes per session
Aerobic Exercise Group
Group will undergo 30 sessions of aerobic exercise training over approximately 10 weeks. Sessions will require subjects to exercise on a cycle ergometer for up to 45 minutes per session. Aerobic Exercise Group: 30 sessions of aerobic exercise training for 45 minutes at 60% of VO2peak
Protocol 1
STARTED
21
20
Protocol 1
COMPLETED
21
20
Protocol 1
NOT COMPLETED
0
0
Protocol 2
STARTED
17
14
Protocol 2
COMPLETED
15
12
Protocol 2
NOT COMPLETED
2
2

Reasons for withdrawal

Reasons for withdrawal
Measure
Heat Therapy Group
Group will undergo 30 sessions of heat therapy over approximately 10 weeks. Sessions will require subjects to be immersed in hot water for up to 45 minutes per session. Heat Therapy Group: 30 sessions of immersion in 40.5 degree celsius water for 45 minutes per session
Aerobic Exercise Group
Group will undergo 30 sessions of aerobic exercise training over approximately 10 weeks. Sessions will require subjects to exercise on a cycle ergometer for up to 45 minutes per session. Aerobic Exercise Group: 30 sessions of aerobic exercise training for 45 minutes at 60% of VO2peak
Protocol 2
Withdrawal by Subject
1
1
Protocol 2
Met exclusion criteria at Post timepoint
1
1

Baseline Characteristics

Heat Therapy Versus Exercise Training in Hypertension

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure
Heat Therapy Group
n=21 Participants
Group will undergo 30 sessions of heat therapy over approximately 10 weeks. Sessions will require subjects to be immersed in hot water for up to 45 minutes per session. Heat Therapy Group: 30 sessions of immersion in 40.5 degree celsius water for 45 minutes per session.
Aerobic Exercise Group
n=20 Participants
Group will undergo 30 sessions of aerobic exercise training over approximately 10 weeks. Sessions will require subjects to exercise on a cycle ergometer for up to 45 minutes per session. Aerobic Exercise Group: 30 sessions of aerobic exercise training consisting of a 5-minute warm-up of seated upright cycling at 30% VO2 peak, followed by 40 minutes of cycling at 60% VO2 peak, then a 5-minute cool down at 30% VO2 peak.
Total
n=41 Participants
Total of all reporting groups
Age, Categorical
<=18 years
0 Participants
n=99 Participants
0 Participants
n=107 Participants
0 Participants
n=206 Participants
Age, Categorical
Between 18 and 65 years
21 Participants
n=99 Participants
20 Participants
n=107 Participants
41 Participants
n=206 Participants
Age, Categorical
>=65 years
0 Participants
n=99 Participants
0 Participants
n=107 Participants
0 Participants
n=206 Participants
Age, Continuous
47.57 years
n=99 Participants
47.95 years
n=107 Participants
47.76 years
n=206 Participants
Sex: Female, Male
Female
8 Participants
n=99 Participants
8 Participants
n=107 Participants
16 Participants
n=206 Participants
Sex: Female, Male
Male
13 Participants
n=99 Participants
12 Participants
n=107 Participants
25 Participants
n=206 Participants
Ethnicity (NIH/OMB)
Hispanic or Latino
1 Participants
n=99 Participants
0 Participants
n=107 Participants
1 Participants
n=206 Participants
Ethnicity (NIH/OMB)
Not Hispanic or Latino
19 Participants
n=99 Participants
20 Participants
n=107 Participants
39 Participants
n=206 Participants
Ethnicity (NIH/OMB)
Unknown or Not Reported
1 Participants
n=99 Participants
0 Participants
n=107 Participants
1 Participants
n=206 Participants
Race (NIH/OMB)
American Indian or Alaska Native
0 Participants
n=99 Participants
0 Participants
n=107 Participants
0 Participants
n=206 Participants
Race (NIH/OMB)
Asian
0 Participants
n=99 Participants
2 Participants
n=107 Participants
2 Participants
n=206 Participants
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
0 Participants
n=99 Participants
0 Participants
n=107 Participants
0 Participants
n=206 Participants
Race (NIH/OMB)
Black or African American
1 Participants
n=99 Participants
1 Participants
n=107 Participants
2 Participants
n=206 Participants
Race (NIH/OMB)
White
19 Participants
n=99 Participants
17 Participants
n=107 Participants
36 Participants
n=206 Participants
Race (NIH/OMB)
More than one race
0 Participants
n=99 Participants
0 Participants
n=107 Participants
0 Participants
n=206 Participants
Race (NIH/OMB)
Unknown or Not Reported
1 Participants
n=99 Participants
0 Participants
n=107 Participants
1 Participants
n=206 Participants
Region of Enrollment
United States
21 participants
n=99 Participants
20 participants
n=107 Participants
41 participants
n=206 Participants

PRIMARY outcome

Timeframe: 10 weeks

Ambulatory blood pressure (ABP) was measured at baseline (PRE) and after 30 heat therapy or exercise training sessions (POST) over the course of 8-10 weeks. Two individuals performed post-intervention testing after completing only 27 sessions (1 in each group). Participants arrived at the lab and were fitted with an oscillometric blood pressure cuff attached to an ambulatory blood pressure monitor. The monitor was programmed to inflate and assess blood pressure every 20 min during self-reported waking hours and every 60 min during self-reported sleeping hours. Waking and sleeping times and measurement frequency were replicated at POST within each participant. Ambulatory blood pressure data were analyzed as 24-h total for both systolic and diastolic blood pressure. Change was calculated as the value at the POST timepoint minus the value at the PRE timepoint.

Outcome measures

Outcome measures
Measure
Heat Therapy Group
n=21 Participants
Group will undergo 30 sessions of heat therapy over approximately 10 weeks. Sessions will require subjects to be immersed in hot water for up to 45 minutes per session. Heat Therapy Group: 30 sessions of immersion in 40.5 degree celsius water for 45 minutes per session.
Aerobic Exercise Group
n=20 Participants
Group will undergo 30 sessions of aerobic exercise training over approximately 10 weeks. Sessions will require subjects to exercise on a cycle ergometer for up to 45 minutes per session. Aerobic Exercise Group: 30 sessions of aerobic exercise training consisting of a 5-minute warm-up of seated upright cycling at 30% VO2 peak, followed by 40 minutes of cycling at 60% VO2 peak, then a 5-minute cool down at 30% VO2 peak.
Blood Pressure Reduction: Change in Systolic and Diastolic Ambulatory Blood Pressure (mmHg) After 30 Sessions of Intervention
Change in systolic Ambulatory Blood Pressure
-1 mmHg
Interval -4.0 to 3.0
0 mmHg
Interval -3.0 to 4.0
Blood Pressure Reduction: Change in Systolic and Diastolic Ambulatory Blood Pressure (mmHg) After 30 Sessions of Intervention
Change in diastolic Ambulatory Blood Pressure
0 mmHg
Interval -3.0 to 2.0
1 mmHg
Interval -2.0 to 3.0

SECONDARY outcome

Timeframe: 10 weeks

Carotid-femoral pulse wave velocity (m/s) was measured as a marker of arterial stiffness using a pressure transducing tonometer over the carotid artery and an inflated leg cuff to detect the femoral artery pulse waveform using air displacement at baseline (PRE) and after 30 heat therapy or exercise training sessions (POST) over the course of 8-10 weeks. Two individuals performed post-intervention testing after completing only 27 sessions (1 in each group). Change was calculated as the value at the POST timepoint minus the value at the PRE timepoint.

Outcome measures

Outcome measures
Measure
Heat Therapy Group
n=21 Participants
Group will undergo 30 sessions of heat therapy over approximately 10 weeks. Sessions will require subjects to be immersed in hot water for up to 45 minutes per session. Heat Therapy Group: 30 sessions of immersion in 40.5 degree celsius water for 45 minutes per session.
Aerobic Exercise Group
n=20 Participants
Group will undergo 30 sessions of aerobic exercise training over approximately 10 weeks. Sessions will require subjects to exercise on a cycle ergometer for up to 45 minutes per session. Aerobic Exercise Group: 30 sessions of aerobic exercise training consisting of a 5-minute warm-up of seated upright cycling at 30% VO2 peak, followed by 40 minutes of cycling at 60% VO2 peak, then a 5-minute cool down at 30% VO2 peak.
Arterial Stiffness: Change in Carotid-femoral Pulse Wave Velocity (m/s) From Pre (Baseline) to Post (After 30 Sessions of Intervention)
-0.0 meters/second
Interval -0.3 to 0.3
-0.1 meters/second
Interval -0.4 to 0.2

Adverse Events

Heat Therapy Group

Serious events: 0 serious events
Other events: 0 other events
Deaths: 0 deaths

Aerobic Exercise Group

Serious events: 0 serious events
Other events: 0 other events
Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Adverse event data not reported

Additional Information

Dr. Christopher Minson

University of Oregon

Phone: 541-953-2231

Results disclosure agreements

  • Principal investigator is a sponsor employee
  • Publication restrictions are in place