Heat and Exercise in Aging as Therapy (HEAT)

NCT ID: NCT06580964

Last Updated: 2025-09-17

Basic Information

• Recruitment Status: RECRUITING
• Clinical Phase: NA
• Total Enrollment: 54 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2025-07-31
• Study Completion Date: 2029-07-31

Brief Summary

The main goal of this two-phase clinical trial is to learn whether local heat therapy, using heat pads applied to the legs, can enhance skeletal muscle health, physical function, and blood sugar control in a manner comparable to exercise, specifically High-Intensity Interval Training (HIIT), in older individuals with prediabetes. The study aims to answer the following questions:

1. Does local heat therapy improve muscle architecture (e.g., muscle cross-sectional area, capillary density, mitochondrial content), glucose tolerance, and frailty indicators similarly to HIIT in older individuals with prediabetes?

2. Does local heat therapy as a pre-conditioning method enhance the skeletal muscle response to HIIT in older individuals with prediabetes?

Detailed Description

To achieve the study objectives, researchers will first compare the outcomes of local heat therapy to: 1) HIIT and 2) heat pads set to maintain normal skeletal muscle temperature (control group). Then, researchers will compare the outcomes of the local heat therapy and control groups after a subsequent HIIT intervention. This will enable the researchers to assess the effectiveness of local heat therapy (compared to HIIT and preceding HIIT) to improve skeletal muscle health, physical function, blood sugar control.

Study Procedures:

All participants will visit the laboratory over three days at the start of the study for baseline assessments and sample collection.

Participants in the Control (CON) and Local Heat Therapy (LHT) groups will:

Phase 1:

• Use heat pads on both thighs at a pre-determined temperature for 90 minutes daily, 6 days a week (5 days at home and 1 day in the laboratory; 12 laboratory visits) for the first 12 weeks.
• Maintain a log of each heat pad session.
• Visit the laboratory over three days at the end of Phase 1 for follow-up assessments and sample collection.

Phase 2:

• Visit the laboratory three days per week for 12 weeks (a total of 36 visits) for exercise training.
• Visit the laboratory over three days at the end of Phase 2 for final assessments and sample collection.

Participants in the HIIT Group will:

Phase 1:

• Visit the laboratory three days per week for 12 weeks (a total of 36 visits) for exercise training.
• Visit the laboratory over three days at the end of Phase 1 for final assessments and sample collection.

Conditions

Prediabetic State

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: PREVENTION
• Blinding Strategy: SINGLE

Study Groups

Local Heat Therapy

Phase 1: Heat pads will be applied to both legs and set to a pre-determined, optimized temperature to raise the intramuscular temperature to 3-4°C above resting. Each heating session will last for 90 min/d, 6d/wk (5 at-home and 1 in-lab) for 12 wks.

Phase 2: High-intensity interval training will be performed 3 d/wk for 12 wks. Each exercise session will consist of 4 cycling exercise intervals (4 min each) with 3 min active rest between intervals. Interval intensity will progressively increase from 70-75% to 90-95% of VO2peak by the end of week 3.

Group Type: EXPERIMENTAL

Heat therapy

Intervention Type: BEHAVIORAL

Heat pads will be set to a pre-determined, optimized temperature and applied to both legs for 90 min, 6d/wk (5 at-home and 1 in-lab).

High-intensity interval training

Intervention Type: BEHAVIORAL

High-intensity interval training will be performed 3 days per week for 12 weeks.

Thermoneutral Therapy

Phase 1: Heat pads will be applied to both legs and set to a pre-determined temperature to keep the intramuscular temperature in a thermoneutral state (~35-37°C). Each heating session will last for 90 min, 7d/wk (6 at-home and 1 in-lab) for 12 weeks.

Phase 2: High-intensity interval training will be performed 3 d/wk for 12 wks. Each exercise session will consist of 4 cycling exercise intervals (4 min each) with 3 min active rest between intervals. Interval intensity will progressively increase from 70-75% to 90-95% of VO2peak by the end of week 3.

Group Type: SHAM_COMPARATOR

Heat therapy

Intervention Type: BEHAVIORAL

Heat pads will be set to a pre-determined, optimized temperature and applied to both legs for 90 min, 6d/wk (5 at-home and 1 in-lab).

High-intensity interval training

Intervention Type: BEHAVIORAL

High-intensity interval training will be performed 3 days per week for 12 weeks.

High-Intensity Interval Training

Phase 1: High-intensity interval training will be performed 3 d/wk for 12 wks. Each exercise session will consist of 4 cycling exercise intervals (4 min each) with 3 min active rest between intervals. Interval intensity will progressively increase from 70-75% to 90-95% of VO2peak by the end of week 3.

Phase 2: N/A.

Group Type: ACTIVE_COMPARATOR

High-intensity interval training

Intervention Type: BEHAVIORAL

High-intensity interval training will be performed 3 days per week for 12 weeks.

Interventions

Heat therapy

Heat pads will be set to a pre-determined, optimized temperature and applied to both legs for 90 min, 6d/wk (5 at-home and 1 in-lab).

Intervention Type: BEHAVIORAL

High-intensity interval training

High-intensity interval training will be performed 3 days per week for 12 weeks.

Intervention Type: BEHAVIORAL

Eligibility Criteria

Inclusion Criteria

• Age ≥ 50 years
• Women who are postmenopausal, defined as no menstrual period for at least 12 consecutive months.
• Sedentary (structured exercise <30 minutes, 3x/week)
• Body weight is at least 110 lbs
• Meet criteria for prediabetes (fasting blood glucose 100-125 mg/dl, hemoglobin A1c 5.7-6.4%)
• Consume <8 (women) or <15 (men) alcohol-containing beverages per week
• Do not use nicotine or cannabis
• Not taking any medications that could interfere with responses to the interventions (e.g., corticosteroids, opiates, benzodiazepines, tricyclic antidepressants, beta blockers, sulfonylureas, insulin, metformin, anticoagulants, barbiturates, insulin sensitizers, fibrates, immunosuppressants). If you don't know, that's okay. We'll ask what medications you are on and check whether they fall into one of these categories.

Exclusion Criteria

• History of peripheral neuropathies
• Currently taking prescription blood thinners
• Medical complications that could would contraindicate participation in the high intensity interval training (HIIT) intervention including: orthopedic complications that would limit your ability to perform cycling exercise, significant cardiovascular impairments (e.g., history of arrhythmias, severe uncontrolled hypertension, etc.), diagnosed metabolic disease (e.g., diabetes), renal disease, sickle cell anemia, or cancer in remission for <6 months.
• Known history of slow wound healing
• Lidocaine allergy
• Latex allergy
• Currently pregnant
• >1.5" subcutaneous fat over the thigh muscle
• Symptoms suggestive of cardiovascular, respiratory, metabolic, or renal diseases including discomfort, pressure, or pain in your chest, neck, jaw, arms, calves, or other areas potentially related to ischemia; shortness of breath at rest or with mild exertion; dizziness or fainting (syncope); difficulty breathing while lying flat (orthopnea) or sudden nighttime breathing difficulties (paroxysmal nocturnal dyspnea); palpitations or rapid heartbeat (tachycardia); pain or cramping in your legs during physical activity (intermittent claudication); a known heart murmur; swelling in your ankles (edema); unusual fatigue or shortness of breath during routine activities or at rest.

• Minimum Eligible Age: 50 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Texas Tech University

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Hui-Ying Luk, PhD; Danielle Levitt, PhD

Role: PRINCIPAL_INVESTIGATOR

Texas Tech University

Locations

Texas Tech University

Lubbock, Texas, United States

Site Status: RECRUITING

Countries

United States

Central Contacts

Hui-Ying Luk, PhD

Role: CONTACT

huiying.luk@ttu.edu

8068340827

Danielle Levitt, PhD

Role: CONTACT

danielle.levitt@ttu.edu

8068341830

Facility Contacts

Hui Ying Luk, Ph.D.

Role: primary

huiying.luk@ttu.edu

806-834-0827

Danielle Levitt, Ph.D.

Role: backup

danielle.levitt@ttu.edu

806-834-1830

Other Identifiers

R01AG084597

Identifier Type: NIH

Identifier Source: org_study_id

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