Changes in Habitual Physical Activity and Inactivity

Changes in Physical Activity and Inactivity During a 12-week Exercise Training and/or Sedentary Time Intervention

The purpose of this study is to determine if individuals involved in exercise training change habitual activity and inactivity behavior outside of exercise training. Eligible participants were randomly assigned to one of four groups: control, exercise training, sedentary time reduction, or exercise training plus sedentary time reduction. It was hypothesized that participants in the exercise training group will compensate for exercise training by reducing free-living physical activity behavior and increasing sedentary time. Participant free-living behavior was monitored for one week at baseline, 3, 6, 9 and 12 weeks using an activPAL wearable monitor.

Inclusion Criteria:

Eligible participants were those at increased risk of cardiovascular disease, based on meeting two of the following three criteria:

1. Pre-hypertensive: resting blood pressure between 125-160 mm Hg systolic and/or 85-100 mm Hg diastolic,
2. overweight/obese: body mass index (BMI) between 25 and 45 kg∙m-2,
3. high central adiposity: as defined by elevated natural waist circumference (> 102 cm [males] > 88cm [females]), a surrogate measure of visceral fat
4. low aerobic fitness (VO2 peak ≤ 50th percentile of age and sex specific norms)
5. exercising less than three days per week for less than 20 minutes per session for the preceding six months

Exclusion Criteria:

• major orthopedic limitations,
• wheelchair use or musculoskeletal problems that affected mobility,
• life-threatening illness (e.g., terminal cancer),
• chronic diseases (e.g., diagnosed heart disease, diabetes, emphysema) or
• any condition for which a physician did not recommend exercise. Participants were excluded if they had gastric bypass or lap-band surgery within the last year, were taking medication for type II diabetes (e.g. metformin) or beta-blocker medication for high blood pressure.