Sedentary Behavior Interrupted Randomized Controlled Trial (P2)

Epidemiological findings indicate that older adults do not meet physical activity (PA) guidelines \& spend up to 11 hrs/day sitting. Given the high prevalence of sedentary behavior (SB), the higher chronic disease risk in this population, \& the age-associated challenges of meeting traditional PA guidelines, involving longer bouts of moderate PA, the investigators hypothesize that older adult health will benefit from new strategies to interrupt sitting. This protocol "Sedentary Behavior Interrupted: A randomized trial of 3-month effects on biomarkers of healthy aging and physical functioning in the real world (Project 2)" is part of a National Institutes of Aging Program Grant called "Sedentary Time \& Aging Mortality and Physical Function (STAR). The overall purpose of the STAR program to is to better understand how to interrupt sitting time and the consequences for healthy aging in postmenopausal women. This protocol (also referred to Project 2 of the STAR program) is a 3-arm randomized control trial designed to assess ways of interrupting sitting in 405 overweight, postmenopausal women.

Primary Aims:

In our primary biomarker outcomes of glucose regulation (fasting insulin \& glucose, HbA1c, HOMA-IR) \& blood pressure (BP):

1. Investigate the 12 week effects of increased standing and additional brief sit-to-stand compared to attention controls.
2. Investigate the dose-response effects of behavioral change on the biomarkers \& BP.

Secondary aims

1. Assess the effect of changes in standing and sit-to-stand transitions at 12 weeks on physical, emotional \& cognitive functioning.
2. Assess the effect of changes in standing and sit-to-stand transitions at 12 weeks on in vivo skeletal muscle mitochondrial function.

Exploratory aims

1. Explore the possible modifying effect of age on the relationship between intervention conditions \& primary \& secondary outcomes.
2. Explore the psychosocial \& environmental mediators \& moderators of changes in sitting time, standing time, and transitions.
3. Explore differences in outcomes between the 2 sitting interruption conditions.

Eligibility Criteria:
Inclusion Criteria:

1. Female;
2. 55 years of age and above;
3. any ethnicity or race;
4. screened to sit for 7 or more hours per day, perform less than 70 sit-to-stand transitions per day
5. ambulatory;
6. medically stable without any health conditions that would inhibit standing or PA;
7. able to give informed consent \& comply with study protocols;
8. able to read and write fluently in English;
9. able to travel to study visits; and
10. no menstruation for at least one year;
11. BMI 25-45
12. able to walk, stand and transition without high risk of falling.

Exclusion Criteria:

1. Male;
2. younger than 55 years of age;
3. sit for less than 7 hours per day, perform 71 or more sit-to-stand transitions per day
4. mental state that would preclude complete understanding of the protocol or compliance;
5. physical limitations to completing any of the study conditions;
6. menstruation less than one year prior;
7. unable to complete the Short Physical Performance Battery,
8. Active cancer
9. body Mass Index \<25 or \>45kg/m2,
10. use of insulin