Effect of Low Volume Sprint Interval Training on Cardiorespiratory Fitness

NCT07328568 | Active Not Recruiting

• 1 other identifier: R15AG093525
• Study Type: interventional
• Target: 60
• Locations: 1 country
• Sites: 1

Brief Summary

Low levels of physical activity (PA) are related to poor health and greater risk of premature death in adults. Lack of time is cited as a primary barrier to partaking in PA. In the last 20 years, a lot of attention has been directed towards the efficacy of high intensity interval training (HIIT), which consists of brief, intense bursts of PA separated by recovery. One primary benefit of HIIT is a sizable increase in cardiorespiratory fitness (CRF), which enables adults to exercise better and reduce health risks due to the strong link between health status and CRF. Completion of cardiovascular exercise is typically recommended for all adults to increase CRF, yet it takes a lot of time and may be perceived as boring. Alternatively, HIIT requires less time and tends to cause greater feelings of enjoyment in many adults. Hundreds of studies report an increase in CRF in response to HIIT in various groups of adults ranging from athletes and those with obesity, diabetes, cancer, stroke, and even spinal cord injury, which emphasizes the potency of this vigorous form of PA. Yet, many studies are weakened by a small sample size which questions the feasibility of these findings. This randomized controlled trial will test the efficacy and feasibility of a very small amount of HIIT, referred to as reduced exertion high intensity interval training (REHIT), in inactive adults. In the proposed study, REHIT will consist of 2 days per week of 1 to two 10 - 20 second sprints on a stationary bike. The proposed sample will include 60 adults who complete 18 sessions of REHIT over a 9 week period, and their responses will be compared to a non exercising control group. During the study, changes in CRF, fuel metabolism, and psychological responses will be monitored, with the latter outcome shedding light on the overall feasibility of HIIT in inactive adults. Overall, this novel study has profound public health applications as it will assess fitness and health related changes to a small dose of PA in the largest sample to date. If substantial changes in CRF are shown, these data have the potential to modify public health guidelines for implementing PA in inactive adults.

Conditions

Inactivity, Physical; Overweight (BMI > 25); Healthy Participants

Keywords

high intensity interval training; maximal oxygen uptake; fat metabolism; affective valence; body composition; exercise adherence

Outcome Measures

Primary Outcomes (1)

• Cardiorespiratory fitness

  Cardiorespiratory fitness (CRF) is determined by oxygen transport from cardiovascular system to mitochondria and is strongly related to health status and premature mortality. It will be assessed using VO2max testing on a cycle ergometer and expressed in mL/kg/min.

  CRF will be assessed at baseline 48 - 72 hours before the start of training, and at 6 and 12 weeks of training, which represent halfway and end of training. The assessments will be performed at least 24 hours after sessions of exercise training.

Secondary Outcomes (5)

• Fat and Carbohydrate Oxidation

  Fat and carbohydrate oxidation will be measured at baseline before the start of training and at 6 and 12 weeks of training, representing halfway and end of training, and at baseline and at 12 weeks in the non exercising control group.

• Cardiac output

  CO will be measured at baseline and at 6 and 12 weeks of training, representing halfway and the end of training, and at baseline and at 12 weeks in the non exercising control group.

• Enjoyment of REHIT

  This outcome will be assessed during session #2 of each week of training in the exercise training group. So, this outcome will be assessed weekly during all 12 weeks of training.

• Perceived exertion responses to REHIT

  This outcome will be assessed during session #2 of each week of training in the exercise training group. So, this outcome will be assessed weekly during all 12 weeks of training

• Pleasure responses to REHIT

  This outcome will be assessed during session #2 of each week of training in the exercise training group. So, this outcome will be assessed weekly during all 12 weeks of training

Study Arms (2)

Intervention group

EXPERIMENTAL

This group will perform long term REHIT.

Other: High intensity interval training

Non exercising control group

PLACEBO COMPARATOR

This group will not complete REHIT, and will be given the option to complete the training once post testing is performed.

Other: High intensity interval training

Interventions

High intensity interval training OTHER

Participants will complete 24 sessions of REHIT and their responses will be compared to a non exercising control group.

Intervention group; Non exercising control group

Eligibility Criteria

• Age: 18 Years - 64 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64)

You may qualify if:

• Healthy
• BMI \< 35 kg/m2
• younger than 65 yr old
• no joint issues

You may not qualify if:

• Those adults who are currently active and not weight stable
• Adults with BMI \> 35 kg/m2
• Use of medications which may alter study outcomes

Sponsors & Collaborators

• California State University, San Marcos: lead

Study Sites (1)

California State University--San Marcos Human Performance Laboratory

San Marcos, California, 92096, United States

Location

Related Publications (1)

• Astorino TA, Metcalfe RS, Vollaard NBJ. The effect of low volume sprint interval training on cardiorespiratory fitness: study protocol for a definitive randomized controlled trial. Trials. 2026 Mar 23. doi: 10.1186/s13063-026-09647-x. Online ahead of print.

  PMID: 41872855 DERIVED

MeSH Terms

Conditions

Sedentary Behavior; Overweight

Interventions

High-Intensity Interval Training

Condition Hierarchy (Ancestors)

Behavior; Overnutrition; Nutrition Disorders; Nutritional and Metabolic Diseases; Body Weight; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

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

Study Officials

• Todd A Astorino, Ph.D

  California State University, San Marcos

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Masking Details: Investigators are masked to participant randomization which is performed by an individual who has no interaction with participants.
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: This is a randomized controlled trial.

Study Record Dates

• First Submitted: October 31, 2025
• First Posted: January 9, 2026
• Study Start: September 1, 2025
• Primary Completion (Estimated): August 30, 2028
• Study Completion (Estimated): August 30, 2028
• Last Updated: January 9, 2026

Record last verified: 2026-01

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)