Aerobic Training and Non-Exercise Physical Activity (I-CAN)

This study will determine the health benefits of combining exercise training and increasing the amount of physical activity in daily life on the fat around the abdomen, weight, fitness and sensitivity to insulin. Volunteers will participate in one of three groups for 6 months: 1) a control group, 2) exercise training only, or 3) exercise training and increasing physical activity outside of training. The exercise training will follow the public health recommendations for exercise (150 minutes/week of moderate exercise). The group increasing physical activity along with exercise training will be asked to increase physical activity in their daily life (up to 3,000 step/day above their current levels through the use of step counters), and meetings focused on behavior modification. The investigators hypothesize that combining aerobic training and additional physical activity after training will have the most profound reduction on waist circumference and body composition.

The Intervention Composed of Aerobic Training and Non-Exercise Physical Activity (I-CAN) study will investigate the effects of aerobic exercise training and increasing the amount of physical activity outside of training (Non-EX PA) on waist circumference, weight, and other cardiovascular disease risk factors in a prospective pilot trial. The investigators will randomize sedentary (<6,500 steps per day) obese adults with at least one additional cardiovascular risk factor (N= 45) to a: (1) structured aerobic exercise program with no intervention on Non-Ex PA (AERO group, N=15); (2) structured aerobic exercise program with the additional goal of increasing Non-EX PA (AERO-PA group, N=15), or (3) a non-exercise control group (CON, N=15) for 6 months. Exercise groups will participate in the same aerobic training program (50 to 75% VO2 max), designed to be consistent with public health recommendations of 150 minutes per week of moderate physical activity. Non-Ex PA in the AERO group will be tracked throughout the entire 6 month intervention with pedometers capable of counting steps, but not displaying them to the participant (blind mode capable). The AERO-PA group will progressively increase Non-Ex PA throughout intervention using pedometers (a progressive increase of 1,000 to 3,000 steps per day above baseline levels). The AERO-PA group will also participate in lifestyle counseling grounded in the principles of the behavioral change theories to determine/reinforce strategies to increase Non-Ex PA. The primary outcome measure will be change in waist circumference following the intervention. The results of this pilot study will be used to determine the efficacy/feasibility of the intervention, and power a larger trial as an R01 application.

The goal of this group is to maintain their current lifestyle habits during the intervention. participants are asked to make no conscious changes to their physical activity or dietary habits.

The Aerobic training group will participate in 6 months of aerobic training and asked to make no conscious alterations in their physical activity outside of exercise session, or dietary habits

The goal of this group is to perform 6 months of aerobic exercise and increase the amount of physical activity outside of their training sessions. They will be asked to make no conscious changes to their dietary habits

Individuals randomized to the aerobic exercise training group will participate in 6 months of supervised exercise training. Exercise dose (expressed in kilocalories per kg per week [KKW]) during aerobic training will be 8KKW in week 1, 10KKW in week 2 and 12 KKW in week 3. the exercise dose of 12KKW will be maintained throughout the intervention. Pedometers will be worn by participant in blind-mode throughout the intervention, and removed during exercise training sessions. Participants will enter information about whether they wore their pedometer on the study website. Aerobic exercise group participants will be told to make no conscious alterations to their physical activity or dietary habits

The Aerobic Exercise+ Physical Activity Group will participate in the same supervised exercise training intervention as the Aerobic Exercise Group, but will also increase the amount of non-exercise physical activity in their daily lives. After week 6 of intervention, participants will incrementally increase Non-Ex PA until they reach an average of 3,000 steps/day above baseline. Non-Ex PA will be increased with moderate physical activity consistent with daily living (i.e. leisurely walking in the evening, walking the dog etc.). Participants will also periodically have life-style counseling sessions with instructors with expertise in behavioral change support to their dietary habits

Waist circumference will be measured at the natural waist (midway between the inferior border of the rib cage and the superior aspect of the iliac crest) with a Gulick tape measure. Both landmarks (the inferior border of the ribcage and the superior aspect of the iliac crest) will be marked and the distance will be measured to determine the appropriate measurement site. Staff will confirm that: 1) the measurement tape remains horizontal; 2) the tape touches the entire circumference of the participant; 3) abdominal tissue is not compressed; 3) the tape measure is not within abdominal folds; 4) the measurement is taken at the end of normal respiration. The measurement will be repeated an additional time, and the reported value will be the average of these measurements. Both measurements must be within 0.5 cm to be considered acceptable for data purposes.

Fitness will be measured using a modified Balke protocol on a treadmill. Participants will walk at an initial speed of 2.0 mph with 0% grade for the first 3 minutes after which the treadmill speed will increase to 3.0 mph for the next 3 minutes. The treadmill grade will be increased by 2.5% every 3 minutes until volitional exhaustion. Respiratory gases (VO2, CO2) and ventilation will be measured continuously using a True Max 2400 Metabolic Measurement Cart (Parvomedics, Salt Lake City Utah).

Insulin area under the curve (AUC) and glucose AUC will be determined from an oral glucose tolerance test

Participants will wear a Sensewear accelerometer for seven consecutive days, 24-hrs/day. The amount of time spent in sedentary, light and moderate to vigorous physical activity will be calculated

Food Frequency Questionnaire (FFQ) contains approximately 105 items grouped by categories and is completed for both frequency of consumption as well as portion size selections by the individual. The questionnaire, upon completion, provides estimated daily intake values for selected nutrients (kilocalories, macronutrients, and micronutrients) and provides information on food group servings.

Low density lipoproteins, High density lipoproteins, total cholesterol, and triglycerides will be measured

Glucose and insulin AUC will be measured following the injestion of 75 mg glucose solution at baseline and 24 weeks

Inclusion Criteria: Age: 40 to 65 years Body mass index: 30-40 Sedentary status One additional risk factor for cardiovascular disease High waist circumference Exclusion Criteria: Previous heart attack or stroke Type 1 or type 2 diabetes Resting systolic blood pressure >180 mmHg Resting diastolic blood pressure>100 mmHg Plans to be away from the Pitt County area more than 4 weeks in the next 6 months Currently pregnant or plans to become pregnant Not full-filling requirements during the screening process Currently using weight loss medications Gastric banding surgery

Swift DL, Dover SE, Nevels TR, Solar CA, Brophy PM, Hall TR, Houmard JA, Lutes LD. The intervention composed of aerobic training and non-exercise physical activity (I-CAN) study: Rationale, design and methods. Contemp Clin Trials. 2015 Nov;45(Pt B):435-442. doi: 10.1016/j.cct.2015.11.005. Epub 2015 Nov 2.

Swift DL, Nevels TR, Solar CA, Brophy PM, McGee JE, Brewer SB, Clark A, Houmard JA, Lutes LD. The Effect of Aerobic Training and Increasing Nonexercise Physical Activity on Cardiometabolic Risk Factors. Med Sci Sports Exerc. 2021 Oct 1;53(10):2152-2163. doi: 10.1249/MSS.0000000000002675.