Exercise Intensity for Cardiorespiratory Fitness

(REVISE Trial)

Overseen By Robert Ross, PhD

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Robert Ross, PhD

Disqualifiers: Diabetes, Current smokers, Physical impairment, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 8

200 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores how various exercise types affect cardiorespiratory fitness and overall heart health. Researchers aim to determine whether increasing exercise frequency or intensity benefits everyone or if some individuals see no improvement. Participants will join groups with different exercise routines, ranging from low to high intensity and duration. Individuals with a sedentary lifestyle (exercising once a week or less), stable weight, and a BMI between 20 and 40 may be suitable for this trial. The goal is to identify whether some people require alternative strategies beyond standard exercise guidelines. As an unphased trial, this study provides a unique opportunity to enhance understanding of personalized exercise strategies for improved heart health.

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications.

Is there any evidence suggesting that this trial's treatments are likely to be safe?

Research shows that high-intensity interval training (HIIT) is generally safe and most people tolerate it well. Studies have found that HIIT can enhance exercise capacity and improve heart and lung health without causing major problems. The dropout rate from these studies is about 23%, indicating that most participants manage this type of exercise.

For those engaging in low-intensity exercise, current research suggests it's safe and beneficial for improving heart and lung health. Even short exercise sessions, like 10 to 15 minutes, can be effective and reduce health risks.

Overall, past research has shown that different levels of exercise intensity and duration in this study are safe. Always consult a healthcare provider before starting any new exercise program, especially if existing health issues are present. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about this trial because it explores how varying amounts and intensities of exercise can boost cardiorespiratory fitness. Unlike typical exercise recommendations that often suggest moderate activity, this trial dives into the effects of high-intensity workouts in different doses. By understanding how these different exercise regimens impact fitness, the trial aims to uncover more personalized and effective exercise strategies. This could lead to new guidelines that optimize heart and lung health for people with diverse fitness levels and needs.

What evidence suggests that this trial's exercise treatments could be effective for improving cardiorespiratory fitness?

Research shows that high-intensity interval training (HIIT), experienced in this trial as either a high or low amount, greatly improves heart and lung fitness in adults. Studies have found that both high and low amounts of HIIT enhance fitness more than regular moderate exercise or no exercise. In this trial, some participants will engage in low-amount, low-intensity exercise, which evidence suggests can still reduce the risk of heart disease. This indicates that any regular exercise, whether intense or not, can improve heart and lung health. Overall, exercising regularly, regardless of intensity, positively impacts fitness and health. ^{3 6 7 8 9}

Who Is on the Research Team?

Robert Ross, PhD

Principal Investigator

Queen's University

Are You a Good Fit for This Trial?

This trial is for adults who lead a sedentary lifestyle, exercising no more than once a week, have had a stable weight for the past 6 months, and have a BMI between 20-40. It's not suitable for individuals with diabetes, current smokers, those planning to move soon or anyone with physical impairments that make exercise difficult or unsafe.

Inclusion Criteria

You do not engage in physical activity more than once a week.

Your body mass index (BMI) falls between 20 and 40 kg/m2.

Weight stable (± 2 kg) for 6 months prior to the beginning of the study

Exclusion Criteria

Plan to move from the area in next 8 months

Physical impairment which would make the intervention very difficult or unsafe according to doctor's advice

I have diabetes and I currently smoke.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

First Line Therapy

Participants engage in 150 minutes per week of moderate physical activity (MPA) for 16 weeks to assess initial response in cardiorespiratory fitness (CRF) and cardiometabolic risk factors.

16 weeks

4 visits (in-person) every 4 weeks

Increased Exercise Intensity/Amount

Participants who do not respond to first line therapy increase exercise intensity or amount for an additional 16 weeks to evaluate changes in CRF and cardiometabolic risk factors.

16 weeks

4 visits (in-person) every 4 weeks

Follow-up

Participants are monitored for safety and effectiveness after the exercise intervention phases.

4 weeks

What Are the Treatments Tested in This Trial?

Interventions

• High amount, high intensity exercise
• Low amount, high intensity exercise
• Low amount, low intensity exercise

Trial Overview The study is testing how different amounts and intensities of exercise affect cardiorespiratory fitness and cardiometabolic risk factors. Participants will be assigned to one of three groups: low amount/low intensity exercise, low amount/high intensity exercise, or high amount/high intensity exercise.

How Is the Trial Designed?

Group I: Low amount, low intensity exercise Experimental Treatment 1 Intervention

exercise dose (amount and intensity) will be controlled.

Group II: Low amount, high intensity exercise Experimental Treatment 1 Intervention

exercise dose (amount and intensity) will be controlled.

Group III: High amount, high intensity exercise Experimental Treatment 1 Intervention

exercise dose (amount and intensity) will be controlled.

Group IV: Control Active Control 1 Intervention

no exercise intervention

Who Is Running the Clinical Trial?

Robert Ross, PhD

Lead Sponsor

Robert Ross, PhD

Lead Sponsor

Queen's University

Lead Sponsor

Trials

382

Recruited

122,000+

Published Research Related to This Trial

In a study involving 17 inactive obese males, a single session of high-intensity interval exercise (HIIE) and moderate-intensity continuous exercise (MICE) did not lead to significant changes in overall physical activity or sedentary behavior levels over the following week.

Both types of exercise can be safely incorporated into the routines of inactive obese males without negatively impacting their daily activity levels or increasing sedentary time.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effects of High-Intensity Interval and Moderate-Intensity Continuous Exercise on Physical Activity and Sedentary Behavior Levels in Inactive Obese Males: A Crossover Trial. Santos, VOA., Browne, RAV., Souza, DC., et al.[2020]

In a study of 36 male cyclists and triathletes, the individual anaerobic threshold (IAT) was found to be closely aligned with exercise intensities defined as 75% of VO2max and 85% of HRmax, indicating that these measures can be effective for assessing exercise intensity.

However, the study revealed significant variability in how VO2max and HRmax correspond to the IAT, suggesting that using these parameters alone may not accurately reflect physiological responses during exercise, especially at lower intensities.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Is determination of exercise intensities as percentages of VO2max or HRmax adequate? Meyer, T., Gabriel, HH., Kindermann, W.[2022]

High-intensity interval training (HIIT) is as effective, if not more so, than traditional moderate-intensity continuous training (MICT) for patients with cardiovascular disease, based on a systematic review of 23 studies involving 1117 participants.

The safety profile of HIIT in cardiac rehabilitation is promising, with only one major cardiovascular adverse event reported per 17,083 training sessions, indicating that HIIT can be safely implemented in this population.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

High-Intensity Interval Training for Patients With Cardiovascular Disease-Is It Safe? A Systematic Review. Wewege, MA., Ahn, D., Yu, J., et al.[2021]

High-intensity interval training (HIIT) can improve performance in intense exercise events by 2-4% in well-trained athletes after just 6-8 sessions over 2-4 weeks, highlighting its efficacy in enhancing aerobic capacity.

A polarized training approach, where 75% of training is at low intensity and 10-15% at very high intensity, is recommended for elite athletes to optimize metabolic adaptations and performance in events like rowing and track cycling.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Training for intense exercise performance: high-intensity or high-volume training? Laursen, PB.[2022]

In an 8-week study involving 44 healthy men, both high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) improved cardiorespiratory fitness, but the increase in VO2max was not significantly different between the two groups.

MICT was more effective than HIIT in reducing systolic blood pressure, indicating that while HIIT may enhance fitness, MICT may offer better cardiovascular benefits in terms of blood pressure management.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effects of high-intensity interval training compared to moderate-intensity continuous training on maximal oxygen consumption and blood pressure in healthy men: A randomized controlled trial Arboleda-Serna, VH., Feito, Y., Patiño-Villada, FA., et al.[2020]

Low-volume high-intensity interval training (HIIT), involving less than 15 minutes of high-intensity exercise, can lead to significant improvements in cardiorespiratory fitness, glucose control, and blood pressure, comparable to traditional aerobic exercises, but with a much lower time commitment.

This training method is safe and well-tolerated among adults, showing high adherence rates and minimal adverse effects, while its benefits may stem from enhanced mitochondrial function and improved insulin sensitivity.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Low-volume high-intensity interval training for cardiometabolic health. Sabag, A., Little, JP., Johnson, NA.[2022]

This pilot study involving 34 sedentary individuals demonstrated that low-volume high-intensity interval training (HIIT) protocols, performed just 2 times a week for 8 weeks, are feasible and well-tolerated in a community setting, with no adverse events reported.

Both 2×4-minute and 5×1-minute HIIT protocols significantly improved cardiovascular fitness (VO2max) by 20% and 27%, respectively, while requiring 60% less time than traditional moderate-intensity continuous training, highlighting their effectiveness for health promotion.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effects of low-volume high-intensity interval training in a community setting: a pilot study. Reljic, D., Wittmann, F., Fischer, JE.[2018]

A 1-year high-intensity interval training (HIIT) program significantly improved exercise capacity in heart transplant recipients, increasing their VO2peak levels to 89% of predicted values compared to 82.5% in the control group.

The study involved 48 stable heart transplant recipients, and despite the improvements in exercise capacity, there were no adverse effects on cardiac function, indicating that HIIT is a safe and effective exercise option for this population.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

High-intensity interval training improves peak oxygen uptake and muscular exercise capacity in heart transplant recipients. Nytrøen, K., Rustad, LA., Aukrust, P., et al.[2023]

In a study of 21 stable coronary artery disease (CAD) patients, high-intensity aerobic interval exercise (80-90% of VO2peak) resulted in a significant 17.9% increase in peak oxygen uptake (VO2peak) compared to a 7.9% increase with moderate-intensity exercise (50-60% of VO2peak) over 10 weeks.

The findings suggest that high-intensity exercise is more effective than moderate exercise for improving VO2peak in CAD patients, which is important for reducing the risk of cardiovascular disease and mortality.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

High intensity aerobic interval exercise is superior to moderate intensity exercise for increasing aerobic capacity in patients with coronary artery disease. Rognmo, Ø., Hetland, E., Helgerud, J., et al.[2022]

A systematic review of 11 studies involving 156 clinically stable patients with cardiometabolic diseases found that high-intensity interval exercise (HIIE) can lead to adverse responses in about 8% of individuals, indicating a higher risk compared to moderate-intensity exercise.

It is recommended that patients with cardiometabolic diseases who wish to engage in HIIE should be clinically stable, have prior experience with moderate-intensity exercise, and exercise under supervision to ensure safety.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

What Doesn't Kill You Makes You Fitter: A Systematic Review of High-Intensity Interval Exercise for Patients with Cardiovascular and Metabolic Diseases. Levinger, I., Shaw, CS., Stepto, NK., et al.[2022]

High-intensity interval training (HIIT) is a feasible exercise strategy for breast cancer patients undergoing anthracycline-based chemotherapy, with 80% of participants attending the majority of sessions and completing an average of 78 minutes of exercise per week.

The HIIT intervention successfully maintained cardiorespiratory fitness (VO2max) in participants, while the control group experienced a significant decline in VO2max, highlighting the potential of HIIT to counteract the negative effects of chemotherapy on fitness.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Feasibility of high intensity interval training in patients with breast Cancer undergoing anthracycline chemotherapy: a randomized pilot trial. Lee, K., Kang, I., Mack, WJ., et al.[2023]

In a 1-year study involving 186 men with coronary artery disease, both low-intensity (LO) and high-intensity (HI) exercise improved the ventilatory threshold (VT) and peak oxygen uptake (VO2).

High-intensity exercise led to significantly greater improvements in VO2 at VT compared to low-intensity exercise, suggesting that HI may be more effective for enhancing cardiovascular fitness in this population.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Training level comparison study. Effect of high and low intensity exercise on ventilatory threshold in men with coronary artery disease. Jensen, BE., Fletcher, BJ., Rupp, JC., et al.[2022]

Aerobic interval training (AIT) significantly improved peak oxygen uptake in cardiac patients more than the usual care rehabilitation, with AIT participants showing an increase from 31.6 to 36.2 mL·kg(-1)·min(-1) compared to a smaller increase in the usual care group.

AIT was performed at a higher intensity (87.3% of peak heart rate) compared to the usual care group (78.7% of peak heart rate), suggesting that the increased intensity of AIT contributes to its greater effectiveness in enhancing exercise capacity and overall cardiovascular health.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Aerobic interval training increases peak oxygen uptake more than usual care exercise training in myocardial infarction patients: a randomized controlled study. Moholdt, T., Aamot, IL., Granøien, I., et al.[2022]

Moderate-intensity continuous training (MICT) was found to be significantly more effective than sprint interval training (SIT) in improving cardiorespiratory fitness (CRF) among overweight or obese individuals, based on a systematic review of 26 studies with 784 participants.

There was no significant difference in body fat percentage or CRF improvement when comparing MICT to high-intensity interval training (HIIT), suggesting that MICT is a preferable option for enhancing CRF in this population.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Comparison of High-Intensity Training Versus Moderate-Intensity Continuous Training on Cardiorespiratory Fitness and Body Fat Percentage in Persons With Overweight or Obesity: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Rugbeer, N., Constantinou, D., Torres, G.[2022]

Both low-volume and high-volume high-intensity interval training (HIIT) significantly improved heart rate responses in post-myocardial infarction patients, showing that these exercise programs are effective regardless of β-blocker treatment.

Supervised HIIT was more beneficial than just following physical activity recommendations, with low-volume HIIT being a particularly time-efficient option that enhances heart function in this patient group.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Chronotropic Responses to Exercise and Recovery in Myocardial Infarction Patients Taking β-Blockers Following Aerobic High-Intensity Interval Training: AN INTERFARCT STUDY. Jayo-Montoya, JA., Jurio-Iriarte, B., Aispuru, GR., et al.[2022]

Citations

1. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/38760916/

An umbrella review of systematic reviews and meta-analyses Existing evidence from systematic reviews consistently supports the effect of HIIT on enhancing CRF in adults when compared to non-exercise control and MICT.

2. onlinelibrary.wiley.com onlinelibrary.wiley.com/doi/10.1111/sms.14652

High‐intensity interval training and cardiorespiratory fitness ... The majority of reviews indicated that HIIT results in similar or greater improvements in CRF when compared with MICT and other exercise ...

3. nature.com nature.com/articles/s41598-025-11809-x

Effects of high-intensity interval training on physical fitness ... Furthermore, the findings indicate that HIIT significantly enhances cardiorespiratory fitness and reduces body fat percentage, even in ...

4. frontiersin.org frontiersin.org/journals/physiology/articles/10.3389/fphys.2024.1227316/full

High-intensity interval training improves respiratory and ... Results: HIIT significantly improved not only maximal oxygen uptake and minute ventilation, but also maximal heart rate (HR), systolic blood ...

5. bmcsportsscimedrehabil.biomedcentral.com bmcsportsscimedrehabil.biomedcentral.com/articles/10.1186/s13102-025-01176-5

The effectiveness of a high-intensity interval exercise on ... Considering the literature, HIIT significantly improves cardiorespiratory fitness (V̇O₂peak), body composition, and metabolic parameters such as ...

6. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC8294064/

Evidence-Based Effects of High-Intensity Interval Training on ... Research has indicated that high-intensity interval training induces numerous physiological adaptations that improve exercise capacity.

7. sciencedirect.com sciencedirect.com/science/article/pii/S1755296624000486

Can high-intensity interval training improve health ... HIIT may improve cardiorespiratory fitness and reduce drug craving in this population. The pooled dropout rate is 23.08%, with only two dropout cases being ...

8. ahajournals.org ahajournals.org/doi/10.1161/STROKEAHA.124.046564

Cardiorespiratory Fitness Benefits of High-Intensity Interval ... Results have been promising, suggesting that HIIT may be superior for improving mobility, with the greatest gains in V̇O2peak achieved after long ...

9. ama-assn.org ama-assn.org/public-health/prevention-wellness/massive-study-uncovers-how-much-exercise-needed-live-longer

Massive study uncovers how much exercise is needed to ... Participants who performed two to four times above the recommended amount of moderate physical activity had a 26% to 31% lower all-cause mortality and a 28% to ...