The Effect of Training Frequency on Improvements in VO2max With REHIT

NCT ID: NCT05249205

Last Updated: 2024-05-09

Basic Information

• Recruitment Status: SUSPENDED
• Clinical Phase: NA
• Total Enrollment: 45 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2022-02-21
• Study Completion Date: 2025-08-31

Brief Summary

Many people do not manage to do the recommended amount of physical activity for improving general health and wellbeing, and a common reason for this is lack of time. Sprint interval training (SIT) has been suggested to be a time-efficient alternative to current exercise recommendations, but most SIT protocols are not actually as time-efficient as claimed. However, it has previously been shown that the training time commitment of common SIT protocols can be substantially reduced while remaining effective at improving key health markers such as aerobic fitness, insulin function and blood pressure. For example, the reduced-exertion high-intensity interval training (REHIT) protocol consists of two 20-second 'all-out' cycle sprints within a 10-minute low-intensity exercise session. There is some evidence that REHIT is just as effective at improving aerobic fitness with 2 exercise sessions per week compared to 3 or 4 sessions. However, it remains unknown if improvements in aerobic fitness are reduced if just a single REHIT session is performed each week. Therefore, the aim of the present study is to compare improvements in aerobic fitness levels between a control group (no training intervention), a group performing a single REHIT session per week, and a group performing 2 REHIT sessions per week.

Detailed Description

Up to 45 apparently healthy participants will be recruited at multiple sites. Eligible participants will complete a fitness test to measure pre-training maximal aerobic capacity (V̇O2max). Participants will start cycling on a stationary bike at a low intensity (30 W). The intensity will increase by 1 W every 3 seconds until volitional exhaustion or an inability to maintain a pedalling frequency of >60 rpm. Expired O2 and CO2 will be continuously measured breath-by-breath using an online gas analyser. V̇O2max will be determined as the highest value for a 15-breath rolling average of V̇O2. V̇O2max will be accepted if at least 2 of the following criteria are met: volitional exhaustion / inability to maintain a pedal frequency of 60 rpm, RER>1.10, a plateau in V̇O2, and/or heart rate within 10 bpm of the age predicted maximum (220-age).

Participants will then be randomised into one of 3 groups, performing either 1 or 2 REHIT training sessions per week, or no training intervention (control group). Randomisation will be performed using the sealed envelope method. Participants in the control group will be asked to maintain their regular lifestyle for 6 weeks. Participants in the training groups will perform 6 weeks of REHIT. Each REHIT session involves 10 min of unloaded pedalling interspersed with 2 all-out cycle sprints against a resistance equivalent to 7.5% of the participant's body weight. Sprint duration will be 10 s in week 1, 15 s in week 2, and 20 s in the remaining 4 weeks. The first sprint will finish at 2 min and the second sprint will finish at 6 min. Participants will be instructed to start pedalling as fast as they can ~2-3 s before applying the sprint resistance, and to keep pedalling as fast as they can during the sprint. Verbal encouragement will be provided. Heart rate and power output will be measured throughout each 10-minute exercise session. The post-training V̇O2max test will be scheduled 3 days following the last training session.

Conditions

General Health

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: PREVENTION
• Blinding Strategy: NONE

Study Groups

Control

Participants in the control group will be asked to maintain their regular lifestyle for the duration of the study. They will not receive an intervention.

Group Type: NO_INTERVENTION

No interventions assigned to this group

REHIT1

Participants in the REHIT1 group will perform a single REHIT session per week for 6 weeks.

Group Type: EXPERIMENTAL

REHIT1

Intervention Type: BEHAVIORAL

This intervention involves a single REHIT exercise session per week. REHIT involves 10 minutes of unloaded cycling on a stationary bike interspersed with two 20-second 'all-out' cycle sprints against a resistance equivalent to 7.5% of body mass.

REHIT2

Participants in the REHIT2 group will perform 2 REHIT sessions per week for 6 weeks.

Group Type: EXPERIMENTAL

REHIT2

Intervention Type: BEHAVIORAL

This intervention is the same as that for the REHIT1 intervention, but with 2 sessions per week instead of 1.

Interventions

REHIT1

This intervention involves a single REHIT exercise session per week. REHIT involves 10 minutes of unloaded cycling on a stationary bike interspersed with two 20-second 'all-out' cycle sprints against a resistance equivalent to 7.5% of body mass.

Intervention Type: BEHAVIORAL

REHIT2

This intervention is the same as that for the REHIT1 intervention, but with 2 sessions per week instead of 1.

Intervention Type: BEHAVIORAL

Other Intervention Names

Reduced-exertion high-intensity interval training / single session per week; Reduced-exertion high-intensity interval training / 2 sessions per week

Eligibility Criteria

Inclusion Criteria

• Apparently healthy
• Sedentary or recreationally active

Exclusion Criteria

• Classified as highly physically active on the International Physical Activity Questionnaire (IPAQ)
• Answering 'Yes' to any of the questions of a standard Physical Activity Readiness Questionnaire (PAR-Q)
• Resting heart rate >100 bpm
• Resting blood pressure > 140/90 mm Hg
• BMI > 35 kg/m2
• Testing positive for Covid-19
• Pregnant women

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 40 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Swansea University

OTHER

Sponsor Role: collaborator

University of Worcester

OTHER

Sponsor Role: collaborator

University of Stirling

OTHER

Sponsor Role: lead

Responsible Party

Niels Vollaard

Principal investigator

Responsibility Role: PRINCIPAL_INVESTIGATOR

Locations

University of Stirling

Stirling, Stirlingshire, United Kingdom

University of Worcester

Worcester, Worcestershire, United Kingdom

Swansea University

Swansea, , United Kingdom

Countries

United Kingdom

Other Identifiers

NICR4056

Identifier Type: -

Identifier Source: org_study_id