Heat Therapy and High-Intensity Training for Exercise Intolerance

Overseen By Chad Hancock, Ph.D.

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Brigham Young University

Disqualifiers: Pregnancy, Cardiovascular disease, Diabetes, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 3

Duration: 6 weeks

148 Participants Needed

Trial Summary

What is the purpose of this trial?

Exercise tolerance decreases with age and a sedentary lifestyle. Muscle critical power (CP), is a sensitive measure of exercise tolerance that is more even more relevant to and predictive of endurance performance than VO2max. While recent evidence indicates that CP and muscle function decrease with aging, the cause of this decrease in CP and the best way to mitigate the decrease in CP are unknown. This study will: 1. Measure knee extensor CP in young and old individuals and determine the extent to which changes in muscle oxygen delivery (e.g. resistance artery function, maximum exercise blood flow), muscle mass and composition (e.g. whole-muscle size, muscle fiber cross-sectional area) and mitochondrial oxygen consumption (e.g. maximal coupled respiration of permeabilized fibers biopsied from the knee extensors) contribute to the decrease in CP with age. 2. Examine the effectiveness of two different therapies (1. High Intensity Interval Training, HIIT and 2. Muscle Heat Therapy) at improving muscle function and critical power in young and older adults. 3. Examine the impact of muscle disuse (2 weeks of leg immobilization), a potential contributor to the decrease in muscle function with aging, on muscle function and critical power and determine if heat therapy is an effective means of minimizing the impact of disuse on muscle function and critical power.

Research Team

Jayson Gifford, Ph.D.

Principal Investigator

Brigham Young University

Robert Hyldahl, Ph.D.

Principal Investigator

Brigham Young Univeristy

Eligibility Criteria

This trial is for individuals aged 18-95 who can perform knee extension exercises and have no current cardiovascular or metabolic diseases like heart failure or diabetes. It's not suitable for those who are pregnant, have been exercising regularly in the last six months, or cannot do knee extensions.

Inclusion Criteria

You can perform an exercise that involves straightening your knee.

I do not have heart disease or diabetes.

Exclusion Criteria

You are currently pregnant.

I have a heart condition or diabetes.

You are unable to do a specific knee exercise.

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants undergo either High Intensity Interval Training or Muscle Heat Therapy for 6 weeks

6 weeks

3 visits per week (in-person)

Immobilization with Heat Therapy

Participants undergo 2 weeks of leg immobilization with daily heat therapy

2 weeks

Daily visits (in-person)

Follow-up

Participants are monitored for safety and effectiveness after treatment

4 weeks

Treatment Details

Interventions

• High Intensity Interval Training of the Knee Extensors
• Muscle Disuse
• Muscle Heat Therapy
• Sham Heat Therapy

Trial Overview The study tests how well High Intensity Interval Training (HIIT) and Muscle Heat Therapy improve muscle function and exercise tolerance in young and older adults. It also looks at the effects of leg immobilization on these factors and if heat therapy can minimize its impact.

Participant Groups

Group I: Effect of Muscle Heat Therapy Experimental Treatment 1 Intervention

Young and older subjects will participate in single-leg,heat therapy training of a single leg ( quadriceps femoris, 120 minutes of shortwave diathermy to raise the muscle temperature to \~39C) 3 times a week for 6 weeks. Muscle function and knee extensor critical power will be measured before and after the 6 weeks of treatment.

Group II: Effect of Immobilization with Daily Heat Therapy Experimental Treatment 1 Intervention

Young subjects (18-35 years) will undergo 2 weeks of leg immobilization while receiving 2 hours of heat therapy treatment each day. Heat therapy will consist of 120 minutes of shortwave diathermy to raise the quadriceps femoris muscle temperature to \~39C. Muscle function and knee extensor critical power will be measured before and after the 2 weeks of leg immobilization.

Group III: Effect of High Intensity Interval Training Experimental Treatment 1 Intervention

Young and older subjects will participate in single-leg, high-intensity interval training of the right knee extensors (4 intervals of 4 minutes at 80% of max aerobic power with 4 minute rest intervals between, 3x per week for 6 weeks). Muscle function and knee extensor critical power will be measured before and after the 6 weeks of treatment.

Group IV: Effect of Sham Muscle Heat Therapy Placebo Group 1 Intervention

Young and older subjects will participate in a sham treatment of single-leg,heat therapy training of the right knee extensors (120 minutes with shortwave diathermy unit positioned on leg, but not turned on) 3 times a week for 6 weeks. Muscle function and knee extensor critical power will be measured before and after the 6 weeks of treatment.

Group V: Effect of Immobilization with Daily Sham Heat Therapy Placebo Group 1 Intervention

Young subjects (18-35 years) will undergo 2 weeks of leg immobilization while receiving 2 hours of a sham heat therapy treatment each day. For the sham treatment, the heating device will be applied to the limb, but, unbeknownst to the participant, it will not be turned on. Muscle function and knee extensor critical power will be measured before and after the 2 weeks of leg immobilization.

Who Is Running the Clinical Trial?

Brigham Young University

Lead Sponsor

Trials

23

Recruited

10,200+