Heat and Exercise in Aging as Therapy (HEAT)

Official title

Glycemic Control and Frailty Risk in Older People at Risk for Type 2 Diabetes: Impact of Local Heat Therapy

Overview

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.

Interventions

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

Primary outcome measures

• 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)]

Secondary outcome measures (4)

• Anthropometrics 1 [Time frame: Weekly for about 14 (HIIT group) or about 27 (LHT and CON groups) weeks]
• Anthropometrics 2 [Time frame: Weekly for about 14 (HIIT group) or about 27 (LHT and CON groups) weeks]
• Body composition [Time frame: Before intervention, after Phase 1 (at about 12 weeks), and after Phase 2 (at about 24 weeks, except HIIT group)]
• Sleep quality [Time frame: Weekly for about 14 (HIIT group) or about 27 (LHT and CON groups) weeks]

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.

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Single blind

Primary purpose

Prevention

Study locations

United States · 1 center

• Texas Tech University — Lubbock

Identifiers

NCT: NCT06580964 · R01AG084597

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗