Clinical trial NCT02164474: Small Steps for Big Changes
Official title: Time-efficient High-intensity Interval Training Versus Moderate-intensity Continuous Aerobic Training for Promoting Exercise Adherence: A Randomized-controlled Trial
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Physical Activity
Lead sponsor: University of British Columbia
Sponsor class: OTHER
Collaborators: name: Canadian Institutes of Health Research (CIHR)
First posted: 2014-06-16
Enrollment: 100
Sex: ALL
Minimum age (years): 30
Maximum age (years): 65
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: PREVENTION

Brief summary: Exercise is a proven strategy for preventing type 2 diabetes. Traditionally individuals have been prescribed moderate-intensity continuous aerobic exercise but adherence to this standard exercise program is dismal. High-intensity interval training (HIIT) is a novel form of exercise that involves brief, repeated bursts of vigorous exercise separated by periods of recovery. HIIT elicits many favourable cardiometabolic adaptations that are similar to traditional exercise but does so with a lower amount of exercise and in substantially less time than moderate-intensity continuous exercise. Therefore, HIIT has been touted as a "time-efficient" exercise strategy for improving health. Whether overweight individuals at risk for pre diabetes will show greater adherence to HIIT than moderate-intensity continuous exercise over the long-term (12-months) has not been tested. Because exercise adherence requires complex self-regulation, interventions designed to improve adherence should include a behavioural component. The investigators will assess adherence to HIIT and moderate-intensity continuous exercise over 12 months following a short-term (2 week) intervention of either HIIT or moderate-intensity continuous exercise. Both conditions will include a self-regulatory component targeted to increase participants' confidence to engage in regular, independent exercise. The results will help determine whether HIIT is a more feasible option for promoting exercise adherence for pre diabetes prevention than the traditional moderate-intensity continuous exercise. The investigators hypothesize that a) over the 12 months follow-up subjects randomized to the HIIT will be more likely to adhere when compared to moderate-intensity continuous exercise, b) over the 12 months follow-up subjects randomized to HIIT will have higher rates of adherence and levels of total physical activity, c) greater increases in self-regulation (including goal setting, self-monitoring, and self-regulatory efficacy) following HIIT will mediate higher rates of adherence, d) 10-days of HIIT and moderate-intensity continuous exercise will improve cardiorespiratory fitness, increase insulin sensitivity, reduce circulating inflammatory markers, and improve glucose control and e) Improvements in cardiometabolic health factors will be greater following HIIT compared to moderate-intensity continuous exercise.

Detailed description: Eligible participants will be randomized to the HIIT or moderate-intensity continuous exercise conditions. Each condition will involve a two-week supervised exercise period consisting of ten sessions. Exercise prescriptions for each condition will be progressive in nature over the two week supervised period and will be matched for external work. Specifically, individuals randomized to HIIT will begin with four intervals lasting 1-minute each at \~85-90% peak oxygen uptake \[VO2peak\] and increased to 10 X 1-min intervals by day 10. Individuals randomized to moderate-intensity exercise condition will begin with 20 minutes of continuous activity at \~55-60% V02peak and gradually increase the duration to 50 minutes by day 10. Participants will self-select exercise modality (walking outdoors, elliptical machine, treadmill walking, or stationary cycling). One trainer will supervise participants during the 2-week training program. Participants will complete 3 of the 10 training days (day 4, 7 and 9) at home unsupervised. Participants will wear a heart rate monitor during each exercise session (supervised and unsupervised) to monitor exercise intensity and ensure compliance. In addition, participants will record their exercise bouts in a logbook on both lab and home training days.

Participants in both conditions received 10 minutes of behavioural counseling each day they trained in the lab (for a total of 70 minutes). Following the supervised training, participants will be instructed to maintain HIIT or moderate-intensity continuous exercise three days per week independently. Specifically, individuals randomized to HIIT will be prescribed three exercise sessions per week involving 10 X 1-minute intervals at \~85-90% VO2peak, while participants randomized to moderate-intensity continuous exercise will be prescribed three session per week of 50-minute continuous exercise at \~55-60% VO2peak. Training logs will be provided and participants will be instructed to estimate exercise intensity based on physiological cues taught during supervised training days.

Eligibility criteria: Inclusion Criteria:

* Aged 30-65
* Physically inactive (engaging in 2 or less aerobic exercise bouts per week in the last 6 months)
* BMI between 24-40 kg/m2
* Cleared to engage in vigorous exercise (via PARQ+ and, if advised by this validated tool further clearance by their family physician)

Exclusion Criteria:

* Any contraindications to exercise (e.g., musculoskeletal injury)
* Failure to obtain medical clearance to engage in vigorous intensity exercise following a positive PARQ+ screening
* Prior history of cardio- or cerebrovascular disease or myocardial infarction
* Diagnosed with type 2 diabetes
* Currently taking glucose-lowering medications (e.g., metformin), Hypertension that is not controlled by medication (systolic blood pressure (BP) \>160 mmHg and/or diastolic BP \>99 mmHg)
* Change in cardiovascular medications (e.g., statins) in the previous 6 months Class III obesity (BMI \>40 kg/m2).

Primary outcomes:
measure: Change from baseline in cardiorespiratory fitness (VO2peak) at 6 and 12-month follow-up
timeFrame: Baseline, 6-month follow-up and 12-month follow-up
Secondary outcomes:
measure: Self reported adherence to exercise prescription
timeFrame: Exercise log book filled in for a 12-month duration
measure: Changes from baseline in objectively measured moderate-to-vigorous physical activity in bouts ≥10 minutes (MVPA10+) at 3-, 6-, 9-, and 12-months follow-up
timeFrame: Baseline, 3-, 6-, 9-, 12-month follow-up
measure: Changes in efficacy beliefs
timeFrame: Baseline, Post-Intervention, 6-, 12-month follow-up
measure: Changes in body composition
timeFrame: Baseline, post Intervention, 12-month follow-up
Other outcomes:
measure: Changes in insulin sensitivity and inflammation
timeFrame: Baseline, post-intervention, 12-month follow-up
measure: Changes in acute affect during exercise sessions
timeFrame: Repeated measurements on Day 1, Day 6 and Day 9 of the intervention
measure: Changes in exercise enjoyment
timeFrame: Baseline, post intervention, 6- and 12-month follow-up
measure: Changes from baseline in average blood glucose at day 9 of the intervention
timeFrame: Baseline, Intervention day 9
measure: Change in Affective and Instrumental Attitudes
timeFrame: Baseline, intervention day 6, post-intervention, 12-month follow-up
Locations:
city: Kelowna
country: Canada
facility: Health and Exercise Psychology Laboratory
state: British Columbia
Study officials:
affiliation: University of British Columbia
name: Mary E Jung, PhD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Little JP, Safdar A, Wilkin GP, Tarnopolsky MA, Gibala MJ. A practical model of low-volume high-intensity interval training induces mitochondrial biogenesis in human skeletal muscle: potential mechanisms. J Physiol. 2010 Mar 15;588(Pt 6):1011-22. doi: 10.1113/jphysiol.2009.181743. Epub 2010 Jan 25.
citation: Little JP, Gillen JB, Percival ME, Safdar A, Tarnopolsky MA, Punthakee Z, Jung ME, Gibala MJ. Low-volume high-intensity interval training reduces hyperglycemia and increases muscle mitochondrial capacity in patients with type 2 diabetes. J Appl Physiol (1985). 2011 Dec;111(6):1554-60. doi: 10.1152/japplphysiol.00921.2011. Epub 2011 Aug 25.
citation: Hood MS, Little JP, Tarnopolsky MA, Myslik F, Gibala MJ. Low-volume interval training improves muscle oxidative capacity in sedentary adults. Med Sci Sports Exerc. 2011 Oct;43(10):1849-56. doi: 10.1249/MSS.0b013e3182199834.
citation: Trost SG, Owen N, Bauman AE, Sallis JF, Brown W. Correlates of adults' participation in physical activity: review and update. Med Sci Sports Exerc. 2002 Dec;34(12):1996-2001. doi: 10.1097/00005768-200212000-00020.
citation: Jung ME, Wright WL, Wright AE, Ainslie PN, Little JP. Does the Relationship Between Affect and Exercise Intensity Apply to High-Intensity Interval Exercise? Medicine & Science in Sports & Exercise. 2012;44(5S):85.
citation: Bourne JE, Little JP, Beauchamp MR, Barry J, Singer J, Jung ME. Brief Exercise Counseling and High-Intensity Interval Training on Physical Activity Adherence and Cardiometabolic Health in Individuals at Risk of Type 2 Diabetes: Protocol for a Randomized Controlled Trial. JMIR Res Protoc. 2019 Mar 26;8(3):e11226. doi: 10.2196/11226.
citation: Bourne JE, Ivanova E, Gainforth HL, Jung ME. Mapping behavior change techniques to characterize a social cognitive theory informed physical activity intervention for adults at risk of type 2 diabetes mellitus. Transl Behav Med. 2020 Aug 7;10(3):705-715. doi: 10.1093/tbm/ibz008.
citation: Barry JC, Simtchouk S, Durrer C, Jung ME, Mui AL, Little JP. Short-term exercise training reduces anti-inflammatory action of interleukin-10 in adults with obesity. Cytokine. 2018 Nov;111:460-469. doi: 10.1016/j.cyto.2018.05.035. Epub 2018 Jun 6.