Recruiting

Heat Therapy & HIIT

Sponsor:

Texas Tech University

Code:

NCT06580964

Conditions

Prediabetic State

Eligibility Criteria

Sex: All

Age: 50+

Healthy Volunteers: Not accepted

Interventions

Heat therapy

High-intensity interval training

Study Details

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?

Conditions

Prediabetic State

Study ID

NCT06580964

Start date

Nov 6, 2025

Status verified date

Jun, 2026

Completion date

Jul 31, 2029

Anticipated

Primary completion date

Jan 31, 2029

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 50+

Healthy Volunteers: Not accepted

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.

Study Design

Enrollment

54 participants

Anticipated

Allocation

Randomized

Intervention Model

Parallel Assignment

Primary purpose

Prevention

Interventions and Outcome Measures

Arms

experimental: 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.

sham comparator: 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.

active comparator: 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.

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).

High-intensity interval training

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

Primary outcome measure

  • Glycemic control [ Time Frame: Before intervention, after Phase 1 (at about 12 weeks), and after Phase 2 (at about 24 weeks, except HIIT group) ]
  • Skeletal muscle architecture 1 [ Time Frame: Before intervention, after Phase 1 (at about 12 weeks), and after Phase 2 (at about 24 weeks, except HIIT group) ]
  • Skeletal muscle architecture 2 [ Time Frame: Before intervention, after Phase 1 (at about 12 weeks), and after Phase 2 (at about 24 weeks, except HIIT group) ]
  • Frailty status [ Time Frame: Before intervention, after Phase 1 (at about 12 weeks), and after Phase 2 (at about 24 weeks, except HIIT group) ]
  • Exercise capacity [ Time Frame: Before intervention, after Phase 1 (at about 12 weeks), and after Phase 2 (at about 24 weeks, except HIIT group) ]

Central Contacts and Locations

Central contacts

Hui-Ying Luk, PhD

8068340827huiying.luk@ttu.edu

Danielle Levitt, PhD

8068341830danielle.levitt@ttu.edu

Locations

Texas Tech University

Recruiting

Lubbock, Texas, United States, 79409

Contacts

Hui Ying Luk, Ph.D.

806-834-0827huiying.luk@ttu.edu

Danielle Levitt, Ph.D.

806-834-1830danielle.levitt@ttu.edu

Principal Investigator:

Hui Ying Luk, Ph.D.

More Information

Sponsor

Texas Tech University

Last update posted

Jun 23, 2026

Last verified

Jun, 2026

Keywords

  • Exercise
  • Heat
  • Aging
  • Prediabetes
  • Skeletal Muscle

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-09. This information was provided to ClinicalTrials.gov by Texas Tech University on 2026-06-23.