Heat Therapy and Muscle Function Study

Brigham Young University (BYU)

Status: Enrolling

Conditions: High Intensity Interval Training; Aging; Exercise Intolerance; Heat Therapy

Treatments: Other: Sham Heat Therapy; Other: Muscle Disuse; Other: Muscle Heat Therapy; Other: High Intensity Interval Training of the Knee Extensors

Study type: Interventional

Funder types: Other

Identifiers

NCT04733287

F2020-023

Details and patient eligibility

About

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.

Enrollment: 148 estimated patients

Sex: All

Ages: 18 to 95 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• 18-95 years of age
• Currently no cardiovascular or metabolic disease (e.g. heart failure, diabetes)
• ability to perform knee extension exercise

Exclusion criteria

• Pregnant
• Current cardiovascular or metabolic disease (e.g. heart failure, diabetes)
• participating in exercise training within the last 6 months
• inability to perform knee extension exercise

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Single Blind

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148 participants in 5 patient groups

Effect of High Intensity Interval Training

Experimental group

Description:

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.

Treatment:

Other: High Intensity Interval Training of the Knee Extensors

Effect of Muscle Heat Therapy

Experimental group

Description:

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.

Treatment:

Other: Muscle Heat Therapy

Effect of Sham Muscle Heat Therapy

Sham Comparator group

Description:

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.

Treatment:

Other: Sham Heat Therapy

Effect of Immobilization with Daily Sham Heat Therapy

Sham Comparator group

Description:

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.

Treatment:

Other: Sham Heat Therapy

Effect of Immobilization with Daily Heat Therapy

Experimental group

Description:

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.

Treatment:

Other: Muscle Disuse