Effect of Ethnicity on Changes in VO2max and Cardiac Output in Response to Short-Term High Intensity Interval Training


The purpose of this study was to determine if ethnicity alters training responsiveness to a low dose of high intensity interval training in inactive women.

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Non-Randomized
    • Intervention Model: Sequential Assignment
    • Primary Purpose: Prevention
    • Masking: None (Open Label)
  • Study Primary Completion Date: December 22, 2019

Detailed Description

Prior to the session, women completed a 4-minute warmup at 10 % PPO. Each subject completed 9 sessions of HIIT over a 3-week period which consisted of eight to ten 1-minute bouts of cycling at 85% PPO with 75-second recovery between bouts at 10 % PPO. This protocol is well-tolerated in inactive individuals. Continuously during each session, heart rate was monitored using telemetry. On days 1, 3, 6, and 9 of training, the physical activity enjoyment scale (PACES) was completed. VO2max and cardiac output max were assessed prior to training, as well as post.


  • Other: High intensity interval training
    • Repeated, brief, and intense exercise bouts separated by active recovery

Arms, Groups and Cohorts

  • Experimental: Caucasian
    • Participants performed 9 sessions of HIIT over 3 weeks, utilizing progressive overload by increasing the number of bouts by 1 each week. They started with 8 bouts on week 1, 9 bouts on week 2, and 10 bouts on week 3.
  • Experimental: Hispanic
    • Participants performed 9 sessions of HIIT over 3 weeks, utilizing progressive overload by increasing the number of bouts by 1 each week. They started with 8 bouts on week 1, 9 bouts on week 2, and 10 bouts on week 3.

Clinical Trial Outcome Measures

Primary Measures

  • Change in baseline in VO2max at 3 weeks
    • Time Frame: 3 weeks
    • Each participant performed VO2max testing on an electronically-braked cycle ergometer using a ramp protocol. During exercise, subjects expired through a plastic mouthpiece and low resistance valve into tubing connected to a mixing chamber. Measures of ventilation and expired fractions of oxygen and carbon dioxide were obtained throughout exercise by a metabolic cart. Gas exchange data including VO2, VCO2, and ventilation were time-averaged every 15 seconds. The test was terminated when the subject’s pedal cadence was below 50 rev/min.
  • Change in baseline in cardiac output max at 3 weeks
    • Time Frame: 3 weeks
    • During the VO2max assessment, participants wore a thoracic impedance device to measure heart rate and stroke volume, calculating their cardiac output.

Participating in This Clinical Trial

Inclusion Criteria

  • Women
  • Between the age of 18-45
  • Healthy and non-obese (BMI < 30 kg/m2)
  • Perform less than 150 minutes per week of exercise in the last 12 months
  • 100% Caucasian or 100% Hispanic

Exclusion Criteria

  • Injured
  • Obese
  • Active
  • Mixed ethnicity

Gender Eligibility: Female

Minimum Age: 18 Years

Maximum Age: 45 Years

Are Healthy Volunteers Accepted: Accepts Healthy Volunteers

Investigator Details

  • Lead Sponsor
    • California State University, San Marcos
  • Provider of Information About this Clinical Study
    • Principal Investigator: Todd A. Astorino Ph.D, PhD, FACSM – California State University, San Marcos
  • Overall Official(s)
    • Todd Astorino, PhD, Principal Investigator, California State University, San Marcos


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Skinner JS, Jaskólski A, Jaskólska A, Krasnoff J, Gagnon J, Leon AS, Rao DC, Wilmore JH, Bouchard C; HERITAGE Family Study. Age, sex, race, initial fitness, and response to training: the HERITAGE Family Study. J Appl Physiol (1985). 2001 May;90(5):1770-6.

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