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Completed

NCT Number: NCT03376685

The Relationship Between Exercise Frequency, Intensity, and Restoration of Cardiometabolic Health

Regular physical activity is well established to decrease the risk of cardiometabolic diseases. While research has characterized responses based on exercise intensity, many beneficial effects of exercise are transient in nature, and therefore exercise frequency may play an important, yet currently under-appreciated, role in improving health. The purpose of this study is to determine the efficacy of 6-week high-frequency endurance (END) or low-frequency sprint (SIT) training with respect to reducing clinically relevant cardiometabolic risk factors in overweight/obese males. It is hypothesized that END, performed at a greater frequency than SIT, will markedly improve cardiometabolic health, while low-frequency SIT will not.

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Key information

Conditions

Overweight or Obesity Body Weight Nutrition Disorders Nutritional and Metabolic Diseases Obesity Overnutrition Overweight Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

18 year–70 year

Sex eligibility

Male

Study type

Interventional

Phase

Not applicable

Primary location

University of Guelph

Guelph, Ontario, N1G 2W1, Canada

About this study

Involvement in regular physical activity is known to elicit systemic adaptations and reduce the risk of cardiometabolic diseases, including hypertension, obesity, dyslipidemia, and hyperglycemia. Traditional physical activity recommendations suggest that 150 minutes of moderate-intensity continuous endurance (END) exercise dispersed over 5 days per week is sufficient to improve physical fitness in adults. However, given the commonly cited barrier of "lack of time," literature has recently focused on time effective sprint interval training (SIT), obtaining equivalent increases in aerobic capacity and acute glycemic regulation compared to classical END exercise when protocols are work-matched. Despite these similarities, END is conducive to daily sessions not feasible of SIT. As improvements in many clinically relevant risk factors are transient in nature following exercise, it remains imperative to assess the implications of variable frequency exercise regimes performed as per general practice (i.e. high-frequency END, low-frequency SIT). Furthermore, improvements in cardiovascular outcomes following END have been shown, in some instances, to be absent in response to SIT, suggesting END may be more beneficial for cardiovascular health. Therefore, the current study aims to assess several markers of cardiovascular (aerobic capacity, blood pressure, arterial stiffness, vascular endothelial function) and metabolic (glucose tolerance, lipid tolerance, body composition) health following 6-weeks of high-frequency END or low-frequency SIT, performed as per general practice. Combined, this research will provide important insight into the under-appreciated role of exercise frequency for improving cardiometabolic health.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Male, aged 18-70 years
  • Body mass index (BMI) > 25 kg/m^2 (classified as overweight or obese)
  • Sedentary (<100 minutes moderate physical activity per week)
  • Approval for vigorous exercise via physical activity readiness questionnaire (PARQ+)

Exclusion criteria

  • Prescribed with glucose lowering medications
  • Smoker
  • Not cleared for physical activity

Treatment and study plan

Endurance Exercise Training (END)

Behavioral

Physical activity will be conducted on cycle ergometers under supervision. Participants will exercise 5 days a week for 30 minutes (Week 1-2); 35 minutes (Weeks 3-4); or 40 minutes (Weeks 5-6) at 60% VO2 peak.

Sprint Exercise Training (SIT)

Behavioral

Physical activity will be conducted on cycle ergometers under supervision. Participants will exercise 3 days a week involving a 3-minute warm-up, followed up 4 repetitions (Week 1-2); 5 repetitions (Weeks 3-4); or 6 (Weeks 5-6) repetitions of 30 seconds at a maximal intensity with 2 minutes' rest in between. Exercise will conclude with a 2-minute cool-down.

Primary outcomes

  1. Cardiorespiratory fitness

    Time frame: Baseline (pre-training) vs. week 6 (post-training)

    Assessed via VO2 peak test, to determine the change in cardiorespiratory fitness following 6-weeks of exercise training

  2. Free-living glycemic regulation

    Time frame: Baseline (pre-training) vs. week 6 (post-training)

    Assessed via continuous glucose monitoring (CGM), to determine the change in free-living glycemic regulation following 6-weeks of exercise training

  3. Glucose tolerance

    Time frame: Baseline (pre-training) vs. week 6 (post-training)

    Assessed via an oral glucose tolerance test (OGTT) to determine changes in standardized glycemic regulation following 6-weeks of exercise training

Secondary outcomes

  1. Blood lipids

    Time frame: Baseline (pre-training) vs. week 6 (post-training)

    Blood lipid profile from fasted venous blood sampling, including high-density lipoproteins (HDL), low-density lipoproteins (LDL), high-sensitivity C-reactive protein (Hs-CRP), cholesterol, non-HDL cholesterol, triglycerides (TAG), free-fatty acids (FFA), and cholesterol/HDL ratio

  2. HbA1C

    Time frame: Baseline (pre-training) vs. week 6 (post-training)

    Change in HbA1C assessed via fasted venous blood sampling, following 6-weeks of exercise training

  3. Post-prandial blood lipids

    Time frame: Baseline (pre-training) vs. week 6 (post-training)

    Assessed following the consumption of an oral fat tolerance test (OFTT). Blood lipid responses include triglycerides (TAG) and free fatty acids (FFA), assessing the influence of 6-weeks of exercise training on these parameters

  4. Blood pressure

    Time frame: Baseline (pre-training) vs. week 6 (post-training)

    Assessed via automated brachial blood pressure (including systolic (SBP), diastolic (DBP), and mean arterial pressure (MAP))

  5. Body composition

    Time frame: Baseline (pre-training) vs. week 6 (post-training)

    Assessed via dual-energy X-ray absorptiometry (DXA); including total and regional lean and fat mass. Assessed via height and weight measurements to determine BMI.

  6. Arterial stiffness

    Time frame: Baseline (pre-training) vs. week 6 (post-training)

    Assessed via carotid-femoral pulse wave velocity (PWV)

  7. Arterial stiffness acutely post-exercise

    Time frame: Acutely pre-exercise vs. post-exercise in week 1 of training

    Assessed via carotid-femoral pulse wave velocity (PWV) following a single bout of exercise in week 1 of each group

  8. Brachial artery vascular function

    Time frame: Baseline (pre-training) vs. week 6 (post-training)

    Assessed via brachial artery flow mediated dilation (FMD) following 6-weeks of exercise training

  9. Brachial artery vascular function acutely post-exercise

    Time frame: Acutely pre-exercise vs. post-exercise in week 1 of training

    Assessed via brachial artery flow mediated dilation (FMD) following a single bout of exercise in week 1 of each training group

  10. Daily sedentary/active time

    Time frame: Baseline (pre-training), week 1 (of training), week 6 (post-training)

    Assessed via accelerometer

  11. Free-living glycemic regulation during the first week of exercise training

    Time frame: Baseline (pre-training) vs. week 1 (of training)

    Assessed via continuous glucose monitoring (CGM)

Sponsors and collaborators

Lead sponsor

University of Guelph

Other

Registry information

Important dates

Study start
2018
Primary completion
2019
Study completion
2019
First posted
Dec 18, 2017
Registry last updated
Apr 29, 2020

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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