Progressive Metabolic Adaptations to Low Intensity Exercise Training and Weight Loss

the investigators first aim is to determine the effect of low intensity exercise (without weight loss) on insulin sensitivity, muscle lipid metabolism, and factors regulating these processes in skeletal muscle after 1 day, 2 wks, 12 wks of training, and again after 3 days without exercise in obese adults. the investigators second aim is to determine the effect of combining low intensity exercise training with 10% weight loss on insulin sensitivity, muscle lipid metabolism, and factors regulating these processes in skeletal muscle.

Although a single 40 minute session of exercise at a low exercise intensity will not improve insulin sensitivity, the investigators anticipate adaptations after two weeks of exercise training (6 session/wk; 12 session total) will improve insulin sensitivity and be accompanied by a reduction in fatty acid intermediates and a reduction in markers for pro-inflammatory activation in muscle. the investigators anticipate changes in insulin sensitivity, fatty acid partitioning, and pro-inflammatory markers the day after the last session of a 12 wk training program (without weight-loss) will be similar to that measured after 2 weeks of training. the investigators anticipate insulin sensitivity, accumulation of fatty acid intermediates, and pro-inflammatory activation will be markedly improved after 10% weight loss when measured the day after exercise. the investigators would expect the improvements in Insulin sensitivity, accumulation of fatty acid intermediates, and markers of inflammatory stress will be significantly attenuated when measured 3 days after the most recent exercise session, but beneficial effects of 10% weight loss on these metabolic endpoints will persist when compared with before weight loss.

Study Overview

• Status: Completed
• Conditions: Obesity
• Intervention / Treatment: Other: Exercise Training; Other: Weight Loss with continued Exercise Training

• Study Type: Interventional
• Enrollment (Anticipated): 16
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Michigan
    • Ann Arbor, Michigan, United States, 48109
      • Michigan Clincal Research Unit

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 45 years (Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• body mass index [BMI]: 30-45 kg/m2; All women must be pre-menopausal; Non-exerciser (no regularly planned exercise/physical activity)

Exclusion Criteria:

• Hematocrit ≤ 34%; Fasting plasma glucose concentration ≥ 125 mg/dL; Weight instability ≥ ±5 lbs in past month; Taking medications known to affect lipid and/or glucose metabolism; evidence and/or history of cardiovascular or frank metabolic diseases; pregnancy or actively breast feeding

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Other: Exercise Training with Weight Loss; During the first 12 weeks of the study, subjects will adhere to an exercise training program while maintaining their original body weight. The exercise training program will entail the following: 40min/session, ~50% of their maximal aerobic capacity (approximately 100-110 beats per min), 5-6 days/week After the first 12 weeks in the study, subjects will continue with the same exercise program, but then they will be placed on a reduced calorie diet until they lose exactly 10% of their original body weight

Other: Exercise Training; During the first 12 weeks of the study, subjects will adhere to an exercise training program while maintaining their original body weight. The exercise training program will entail the following: 40min/session, ~50% of their maximal aerobic capacity (approximately 100-110 beats per min), 5-6 days/week; Other: Weight Loss with continued Exercise Training; After the first 12 weeks in the study, subjects will continue with the same exercise program, but then they will be placed on a reduced calorie diet until they lose exactly 10% of their original body weight

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Insulin Sensitivity	A hyperinsulinemic-euglycemic clamp will be used to assess peripheral insulin sensitivity	2-3 hours

Secondary Outcome Measures

Outcome Measure	Time Frame
Meal Tolerance Test	2-3h
Resting Metabolic Rate	20-30 min

Collaborators and Investigators

• Sponsor: University of Michigan
• Collaborators: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Study record dates

Study Major Dates

• Study Start: July 1, 2011
• Primary Completion (Actual): July 18, 2014
• Study Completion (Actual): July 18, 2014

Study Registration Dates

• First Submitted: October 11, 2011
• First Submitted That Met QC Criteria: October 11, 2011
• First Posted (Estimate): October 14, 2011

Study Record Updates

• Last Update Posted (Actual): March 21, 2022
• Last Update Submitted That Met QC Criteria: March 18, 2022
• Last Verified: March 1, 2022

More Information

Terms related to this study

• Keywords: Exercise Training; Weight Loss; Insulin Sensitivity; Fat Metabolism
• Additional Relevant MeSH Terms: Body Weight; Body Weight Changes; Weight Loss
• Other Study ID Numbers: R01 DK077966 - PA; R01DK077966 (U.S. NIH Grant/Contract)