Using heart rate variability index to measure exercise intensity and training load in healthy adults


This research will be looking into the relationship between heart rate variability (HRV) and different forms of aerobic exercise (cycling on a stationary bike). Detrended fluctuation analysis alpha 1 (DFA-­α1) will be used to give us information about HRV in the context of exercise. DFA-­α1 values typically range from 2.0 to 0.0, lower values signify increasing random behavior of successive heartbeats which occurs in periods of increased stress or high exercise intensity. On separate days, volunteers who participate in this study will perform incremental exercise (i.e., maximal exercise tests), continuous heavy-intensity exercise, and time to task failure trials. Participants will exercise while wearing a face mask connected to a metabolic cart to facilitate the analysis of expired gas and a heart rate monitor to measure heart rate variability. From this research, we hope to add clarity on the use of DFA-­α1 as a potential tool to assess exercise intensity and fatigue, ideally providing end users a simpler and more readily available tool for exercise testing and prescription.


Currently recruiting participants: Yes

Eligible gender: Male, Female, Transgender, Other

Eligible ages: 18 to 50

Accepts healthy participants: Yes

Inclusion criteria:

To be eligible to participate in this study, you must
- be between the ages of 18 and 50 years old
- have no contraindications to exercise

Exclusion criteria:

You will not be eligible to participate if you
- are obese (BMI > 30 kg/m2)
- are taking medications known to affect cardiovascular or metabolic responses to exercise (such as β-blockers, anti-inflammatories, anti-coagulants, insulin, etc.)
- are dieting for weight loss or following a low-carbohydrate diet
- are smoking, vaping or using tobacco products (within the past year)
- are consuming excessive amounts of alcohol (>21 units/week)
- have known health problems, such as: renal or gastrointestinal disorders, metabolic disease, heart disease, vascular disease, arthritis, diabetes, respiratory disease, uncontrolled blood pressure, dizziness, thyroid problems, or any other major health conditions that are being treated
- have orthopedic issues that limit exercise capacity
- are using/have used an investigational drug product within the last 30 days
- are pregnant
- have donated blood in the last 90 days
- do not understand English


Fill out the following form if you want to participate in this research

Method of contact

Additional information

Contact information

Timi Ajayi, MSc Student Human Performance Lab, KNB 2220 Faculty of Kinesiology, University of Calgary

Principal investigator:

Martin MacInnis

Clinical trial: