Inclusion Criteria:

• Age 18-60 years.
• Body mass index (BMI) ≥18.5 kg/m².
• Insufficiently physically active, defined as generally not meeting current physical activity guidelines for moderate-to-vigorous physical activity.
• Able to safely participate in moderate-to-vigorous physical activity as determined by study screening procedures, including completion of the Physical - Activity Readiness Questionnaire (PAR-Q+) and health history review.
• Willing and able to provide written informed consent.
• Willing to complete all study visits, wear activity monitors, and comply with study procedures.

Exclusion Criteria:

• Known cardiovascular, pulmonary, metabolic, neurological, orthopedic, or other medical conditions that would make participation in moderate-to-vigorous physical activity unsafe.
• Resting heart rate >100 beats/minute at screening.
• Resting blood pressure >160/100 mmHg at screening.
• Clinically significant electrocardiogram (ECG) abnormalities identified during screening that require medical evaluation.
• Current participation in regular structured physical activity that meets or exceeds recommended physical activity guidelines.
• Physical limitations or injuries that preclude safe participation in the intervention or fitness testing.
• Moderate-to-severe psychological distress or other mental health concerns identified during screening that require referral or would make study participation inappropriate.
• Pregnancy or any other condition judged by the investigators to make participation unsafe or interfere with completion of study procedures.