Work Rate Adjustments During a High-intensity Interval Training on a Stationary Bike in a Hot and Temperate Environment

NCT05988606 | Completed

• 1 other identifier: 21-02-4359
• Study Type: interventional
• Target: 7
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this repeated measures study is to evaluate acute work rate adjustments during high-intensity interval training (HIIT) in a hot and temperate environment in healthy and active adults when using target heart rate to prescribe the exercise intensity. The main questions it aims to answer are:

• Will HIIT based on target heart rate in a hot environment result in increased cardiovascular (i.e., elevated recovery HR) and thermal strain compared to HIIT in a temperate environment?
• Will work rate be lowered to a greater extent during HIIT in a hot environment compared to a temperate environment in order to maintain target heart rate?
• Will maximal aerobic capacity (V̇O2max) decrease to a greater extent after HIIT in the heat compared to a temperate environment? Procedures: Participants will complete 5 trials on a cycle ergometer. Trial 1 (Control Visit): Participants (n = 7) will have their maximal heart rate and V̇O2max measured in a temperate environment (\~22 °C, 40% RH). Experimental Trials 2-5: The order of the trials will be counterbalanced and randomly assigned to participants.
• 15TEMP: Participants will cycle at 70% of their maximum heart rate for 8 minutes as a warm-up, followed by one round of HIIT. The HIIT protocol consists of 4 minutes at 90% of maximum heart rate followed by 3 minutes at 70% of maximum heart rate, totaling 15 minutes, in a temperate environment (\~22 °C, 40% RH). After the HIIT session, a graded exercise test will measure V̇O2max.
• 15HEAT: Similar to 15TEMP, but participants will perform the HIIT protocol in a hot environment (\~35 °C, 40% RH).
• 43TEMP: Participants will cycle at 70% of their maximum heart rate for 8 minutes as a warm-up, followed by the HIIT protocol repeated four times (4 minutes at 90% of maximum heart rate and 3 minutes at 70% of maximum heart rate), totaling 43 minutes, in a temperate environment (\~22 °C, 40% RH).
• 43HEAT: Similar to 43TEMP, but participants will perform the HIIT protocol in a hot environment (\~35 °C, 40% RH).

Conditions

High-Intensity Interval Training; Heat

Outcome Measures

Primary Outcomes (1)

• Work rate adjustments

  In a hot and temperate environment by how much does work rate need to be adjusted to maintain target heart rate?

  From the first work interval (min 9-12) to the last work interval (min 37-40).

Secondary Outcomes (3)

• Cardiovascular strain

  From the first recovery interval (min 13-15) to the last recovery interval (min 41-43).

• Thermal Strain

  From the first work interval (min 9-12) to the last work interval (min 37-40).

• Maximal aerobic capacity

  The end of the 15 min trials compared to the end of the 43 min trials.

Study Arms (5)

15TEMP

EXPERIMENTAL

Participants cycled at 70% heart rate max for 8 min as a warm-up and then completed one round of HIIT, i.e., 4 min at 90% heart rate max followed by 3 min at 70% heart rate max for a total of 15 minutes in a temperate environment, followed by a graded exercise test to measure maximal aerobic capacity.

Behavioral: 15 minutes of high-intensity interval training; Other: Temperate environment

15HEAT

EXPERIMENTAL

Participants cycled at 70% heart rate max for 8 min as a warm-up and then completed one round of HIIT, i.e., 4 min at 90% heart rate max followed by 3 min at 70% heart rate max for a total of 15 minutes in a hot environment, followed by a graded exercise test to measure maximal aerobic capacity.

Behavioral: 15 minutes of high-intensity interval training; Other: Hot environment

43TEMP

EXPERIMENTAL

Participants cycled at 70% heart rate max for 8 min as a warm-up and then performed the HIIT protocol (4 min at 90% heart rate max and 3 min at 70% heart rate max, repeated 4 times for a total of 43 minutes) in a temperate environment followed by a graded exercise test to measure maximal aerobic capacity.

Behavioral: 43 minutes of high-intensity interval training; Other: Temperate environment

43HEAT

EXPERIMENTAL

Participants cycled at 70% heart rate max for 8 min as a warm-up and then performed the HIIT protocol (4 min at 90% heart rate max and 3 min at 70% heart rate max, repeated 4 times for a total of 43 minutes) in a hot environment followed by a graded exercise test to measure maximal aerobic capacity.

Behavioral: 43 minutes of high-intensity interval training; Other: Hot environment

Control

NO INTERVENTION

Participants completed a graded exercise test on a stationary bicycle in a temperate environment (\~ 22 °C (72 °F), \~40% RH) to measure maximal aerobic capacity and maximal heart rate.

Interventions

15 minutes of high-intensity interval training BEHAVIORAL

Participants completed an 8 min warm-up and 1 round of high-intensity interval training

15HEAT; 15TEMP

43 minutes of high-intensity interval training BEHAVIORAL

Participants completed an 8 min warm-up and 5 rounds of high-intensity interval training

43HEAT; 43TEMP

Hot environment OTHER

Participants exercised in a hot environment, \~ 35 °C, \~40% relative humidity.

15HEAT; 43HEAT

Temperate environment OTHER

Participants exercised in a temperate environment, \~ 22 °C, \~40% relative humidity.

15TEMP; 43TEMP

Eligibility Criteria

• Age: 18 Years - 39 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Participants were healthy males and females who are 18 to 39 years of age, recreationally active as defined by the American College of Sports Medicine, performing moderate-intensity aerobic exercise 30 min or more per session for at least 3 sessions per week for at least the past 3 months, and free of metabolic, cardiovascular, and renal disease

You may not qualify if:

• Individuals classified as needing medical clearance according to American College of Sports Medicine (ACSM) Guidelines were not allowed to participate. Needing medical clearance is defined by ACSM as 1) not being physically active and having known cardiovascular, metabolic, or renal disease and asymptomatic; 2) not being physically active and having any signs or symptoms suggestive of cardiovascular, metabolic, or renal disease; 3) participating in regular exercise and having known cardiovascular, metabolic, or renal disease and asymptomatic; or 4) participating in regular exercise and having any signs or symptoms suggestive of cardiovascular, metabolic, or renal disease .

Sponsors & Collaborators

• University of Alabama, Tuscaloosa: lead

Study Sites (1)

The University of Alabama

Tuscaloosa, Alabama, 35487, United States

Location

MeSH Terms

Interventions

High-Intensity Interval Training

Intervention Hierarchy (Ancestors)

Physical Conditioning, Human; Exercise; Motor Activity; Movement; Musculoskeletal Physiological Phenomena; Musculoskeletal and Neural Physiological Phenomena

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: OTHER
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: Participants completed all trials and were compared to themselves.

Study Record Dates

• First Submitted: August 4, 2023
• First Posted: August 14, 2023
• Study Start: May 12, 2021
• Primary Completion: November 14, 2021
• Study Completion: November 14, 2021
• Last Updated: August 14, 2023

Record last verified: 2023-08

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)