Exercise Snacks in Obesity

Participants will be randomized into an Exercise Snacks or a Placebo Exercise group for 12 weeks. The former will involve bodyweight exercises performed with vigorous effort and the latter will involve low-intensity stretching and mobility exercises. Following baseline testing, individualized interventions will be delivered via a customized mobile application ("app") or web platform. Participants will be instructed to perform a minimum of 4 isolated bouts of prescribed exercises per day on at least 5 days per week. Each bout will be one minute in duration. The interventions will be individualized and consider exercise preferences and physical abilities (e.g., fitness, musculoskeletal issues), and be adaptable to multiple environments (e.g., home, work). To facilitate this, participants will have a pre-intervention meeting wherein any physical limitations will be documented, and a research assistant trained in health behaviour change techniques will provide a brief exercise counselling session designed to individualize the intervention to the participant's preferences, abilities, and lifestyle. After 12 weeks, participants will be asked to return to the lab for follow-up testing.

Inclusion criteria

• Aged 35-64 years.
• Habitually engaging in < 150 min moderate-to-vigorous physical activity per week.
• Body mass index 30-45 kg/m2 or 27.5-45 for participants who self-identify as being of Asian or Southeast Asian origin.
• Waist circumference: >88cm for females and >102cm for males, or >80 cm for females and >90 cm for male participants who self-identify as being of Asian or Southeast Asian.
• Not currently diagnosed with a cardiometabolic disease (e.g., coronary artery disease, stroke, diabetes, non-alcoholic fatty liver disease).
• Taking ≤2 commonly prescribed medications for the prevention of cardiometabolic diseases (e.g., statins, antihypertensives).
• Not a current smoker
• Cleared to engage in physical activity using the Get Active Questionnaire and, if applicable, consultation with a health care provider or Qualified Exercise Professional.
• Access to a computer, tablet or smartphone for intervention delivery and tracking.
• Ability to read and write in English.

Exclusion criteria

• Chronic musculoskeletal condition or recent (within 2 years) cardiovascular event preventing participation in exercise.
• Lack of internet access.
• Angina upon exertion assessed by the Rose Angina Questionnaire.
• Prescribed beta-blockers that can compromise the validity of heart rate measurements. during the exercise test.
• Have a scheduled surgical procedure within the next 3-4 months that would prevent exercise participation.
• Currently participating in another clinical trial that interferes with the study procedures.
• Currently pregnant or planning on becoming pregnant during the intervention (i.e., within the next 4 months).
• Uncontrolled high blood pressure (>160/90 mmHg)