Effects of Exercise Training Intensity on Fitness and Insulin Sensitivity in African Americans

NCT02892331 | Completed Results

• 1 other identifier: 1R03DK105297-01A1
• Study Type: interventional
• Target: 52
• Locations: 1 country
• Sites: 1

Brief Summary

African Americans are at a substantially greater type 2 diabetes risk compared to Caucasians; however, very little data are available on the effects of exercise training on type 2 diabetes risk factors in at risk African Americans. The present proposal will evaluate the effects of 6 months of moderate versus vigorous intensity aerobic exercise training on fitness, insulin sensitivity, mitochondrial capacity, skeletal muscle oxidative/insulin sensitivity markers, adiposity, and quality of life in African Americans.

Conditions

Obesity; Insulin Resistance; Sedentary Lifestyle

Keywords

exercise; insulin resistance; mitochondrial function; arterial stiffness; exercise intensity; fitness

Outcome Measures

Primary Outcomes (1)

• Change in Cardiorespiratory Fitness

  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. Maximal oxygen consumption (Liters of O2 per minute) will be measured using a True Max 2400 Metabolic Measurement Cart (Parvomedics, Salt Lake City Utah).

  Baseline and 24 weeks

Secondary Outcomes (17)

• Change in Body Fat Percentage

  Baseline and 24 weeks

• Change in Body Weight

  Baseline and 24 weeks

• Change in Waist Circumference

  Baseline and 24 weeks

• Change in Low Density Lipoprotein

  Baseline and 24 Weeks

• Change in High Density Lipoprotein

  Baseline and 24 Weeks

Study Arms (3)

Control

NO INTERVENTION

This group does not change physical activity during the intervention period, but will receive exercise training after the study is complete

MOD-INT

EXPERIMENTAL

The Moderate intensity exercise training (MOD-INT) group will exercise at a moderate aerobic exercise intensity for 24 weeks

Behavioral: Moderate intensity exercise training (MOD-INT)

HIGH-INT

EXPERIMENTAL

High Intensity exercise training (HI-INT) group will exercise at a high aerobic intensity for 24 weeks

Behavioral: High Intensity exercise training (HI-INT)

Interventions

Moderate intensity exercise training (MOD-INT) BEHAVIORAL

Participants in the MOD-INT group will exercise at the heart rate associated with 45-55% VO2 max. The exercise volume will be 600 MET-minutes per week, which is consistent with current public health guidelines (500-1,000 MET-minutes)

MOD-INT

High Intensity exercise training (HI-INT) BEHAVIORAL

Participants in the HI-INT group will exercise at the heart rate associated with 70-80% VO2 max (heart rate ranges will be updated at mid-intervention CRF assessment). The exercise volume will be 600 MET-minutes per week, which is consistent with current public health guidelines (500-1,000 MET-minutes)3

HIGH-INT

Eligibility Criteria

• Age: 35 Years - 65 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• African American
• Body mass index 30-45 kg/m2
• sedentary/low active (step count ≤ 6,500 step/day)

You may not qualify if:

• willingness to accept group assignment from randomization
• No resistance training and no structured aerobic exercise for \> 20 minutes per day, 3+ days per week, for the last 6 months
• conditions that are contraindicated for exercise training
• Resting blood pressure \> 180 mm Hg systolic and/or \>100 mm Hg diastolic; individuals on blood pressure medications meeting the blood pressure criteria are eligible
• Diagnosis of type 1 or 2 diabetes, and/or fasting glucose \>125 mg/dL
• Medication for the treatment of type 1 or type 2 diabetes
• Bariatric surgery including gastric banding or bypass (potential effects on energy intake)
• Factors that may limit adherence to intervention or affect conduct of the trial
• Unable or unwilling to communicate with staff
• Failure to complete run-in or baseline testing
• Hospitalization for depression or severe mental illness in the last 6 months
• Not physically capable of performing the exercise required of the study protocol
• Consuming more than 14 alcoholic beverages per week
• Plan to be away from the Pitt County area more than 3 weeks in the next 3 months
• Lack support from a primary health care provider or family members

Sponsors & Collaborators

• East Carolina University: lead

Study Sites (1)

East Carolina University

Greenville, North Carolina, 27858, United States

Location

Related Publications (1)

• McGee JE, Barefoot SG, Gniewek NR, Brophy PM, Clark A, Dubis GS, Ryan TE, Houmard JA, Vos P, Raedeke TD, Swift DL. High-intensity exercise to promote accelerated improvements in cardiorespiratory fitness (HI-PACE): study protocol for a randomized controlled trial. Trials. 2019 Aug 8;20(1):484. doi: 10.1186/s13063-019-3611-1.

  PMID: 31395096 DERIVED

MeSH Terms

Conditions

Obesity; Insulin Resistance; Sedentary Behavior; Motor Activity

Condition Hierarchy (Ancestors)

Overweight; Overnutrition; Nutrition Disorders; Nutritional and Metabolic Diseases; Body Weight; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Hyperinsulinism; Glucose Metabolism Disorders; Metabolic Diseases; Behavior

Results Point of Contact

• Title: Damon Swift
• Organization: University of Virginia

dls3s@virgina.edu

(434) 924-1436

Study Officials

• Damon L Swift, Ph.D.

  East Carolina University

  PRINCIPAL INVESTIGATOR

Publication Agreements

• PI is Sponsor Employee: No
• Restrictive Agreement: No

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assistant Professor

Study Record Dates

• First Submitted: August 30, 2016
• First Posted: September 8, 2016
• Study Start: October 1, 2016
• Primary Completion: August 1, 2021
• Study Completion: August 1, 2021
• Last Updated: June 13, 2024
• Results First Posted: June 13, 2024

Record last verified: 2024-06

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)