Clinical trial NCT01997021: Effects of Interrupting Sedentary Time on Glycemic Control in Older Overweight and Obese Adults
Official title: Effects of Interrupting Sedentary Time on Glycemic Control in Older Overweight and Obese Adults
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Metabolic Syndrome
Diabetes
Aging
Keywords: Sedentary behavior
physical activity
older adults
Lead sponsor: University of Colorado, Denver
Sponsor class: OTHER
First posted: 2013-11-27
Enrollment: 25
Sex: ALL
Minimum age (years): 60
Maximum age (years): 85
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: TREATMENT

Brief summary: Increasing physical activity in older adults has important implications for treating obesity related metabolic conditions, however the interaction of aging- and obesity-related declines in physical function may make adding structured exercise particularly challenging for this group. Given these challenges, an alternative prescription to traditional structured exercise, may be short bouts of intermittent walking scattered throughout the day - this may be an effective strategy to increase physical activity, reduce sedentary behavior, and improve glycemic control in overweight/obese older adults. The purpose of this project is to determine how interrupting sedentary time with short bouts of moderate intensity walking affects important metabolic outcomes in older, overweight adults. It would also be of interest to compare the effects of short, frequent interruptions in sedentary behavior to a traditional exercise prescription (continuous 30 min walking bout) on metabolic outcomes (e.g., glycemic control, insulin sensitivity, and 24 h fat oxidation). Thus, the overall aims of the proposed research are to 1) Determine the effect of performing short bouts of moderate-intensity intermittent walking (IW) on glucose and insulin metabolism compared to uninterrupted sitting (US) in older overweight and obese adults. 2) To compare the effects of interrupting sedentary time (IW) vs. a traditional exercise prescription (continuous 30 m walk (CW)) on metabolism.

The investigators hypothesize that interrupting sedentary time with intermittent walking will improve glucose and insulin metabolism compared to uninterrupted sitting and it will be as effective at improving metabolism as a single continuous 30 min walk.


Eligibility criteria: Inclusion Criteria:

* Aged 60-85 yr • BMI 25-35 kg.m-2
* Non-exercisers (\<150 m/wk of moderate intensity exercise)
* Sedentary (\>60% of waking day sedentary)
* Able to walk on a treadmill for 36 continuous minutes at a pace of at least 2.0 mph

Exclusion Criteria:

* Self-reported acute or chronic disease (e.g. diabetes, heart disease, thyroid disease)
* Fasting plasma glucose ≥ 126 mg/dl - participants will not be excluded if they an abnormal post prandial glucose levels (e.g. glucose ≥ 200 mg/dl) following the MTT's.
* Tobacco use (cigarettes, cigars, or chewing tobacco) within the past 6 months
* Females who previously used (\> 6 months) or are currently using any formulation of estrogen-based hormone therapy (e.g., oral Premarin, transdermal 17-estradiol, selective estrogen receptor modulators).
* Resting diastolic blood pressure \> 100 mm mercury or resting systolic blood pressure \> 160 mm mercury
* Contra-indications to exercise (e.g. orthopedic limitations)
* Unable to walk on a treadmill for 36 continuous minutes at a pace of at least 2.0 mph

Primary outcomes:
measure: Incremental area under the glucose curve in response to meal tolerance test (MTT)
timeFrame: Hourly for 5 hours after meal is consumed
measure: Area under the insulin curve in response to meal tolerance test
timeFrame: Hourly for 5 hours after meal is consumed
Secondary outcomes:
measure: Postprandial glycemia in response to meal tolerance test
timeFrame: Continuously for 5 hours after meal is consumed
measure: Insulin sensitivity
timeFrame: Immediately post 24 hr intermittent walking and continuous walking conditions
measure: 24-hr Fat Oxidation
timeFrame: Continuously during 24 hr intermittent walking and continuous walking conditions
measure: 24-hour Glycemic variability
timeFrame: Continuously during 24 hr intermittent walking and continuous walking conditions
Other outcomes:
Locations:
city: Aurora
country: United States
facility: University of Colorado Denver Anschutz Medical Campus
state: Colorado
Study officials:
affiliation: University of Colorado, Denver
name: Kate Lyden, PhD
role: PRINCIPAL_INVESTIGATOR
affiliation: University of Colorado, Denver
name: Ed Melanson, PhD
role: PRINCIPAL_INVESTIGATOR
References: