Fatty Acid Metabolism and Insulin Sensitivity After Exercise in Obesity

Summary

Alterations in fatty acid mobilization and oxidation may be primary adaptations responsible for the improvements in metabolic health after a single session of endurance exercise. The investigators will determine the effect of a single session of endurance exercise on whole-body fatty acid mobilization and oxidation, IMTG concentration and the expression of factors that regulate these processes in skeletal muscle of 11 women with abdominal obesity (age: 18-45y). In addition, the investigators will evaluate how these factors, and exercise, effect insulin signalling and insulin sensitivity. Every effort will be made to recruit subjects from ethnic and minority groups. Before participating in the study, subjects will be informed of all the procedures and potential risks, and they will sign an informed consent form approved by The University of Michigan Institutional Review Board. Eligible volunteers will participate in three separate trials, in a randomized order. In two trials subjects will eat exactly the same amount of calories, except in one trial they will exercise (eucaloric + exercise) and in the other trial they will remain sedentary (hypercaloric). In a third trial subjects will again remain sedentary but instead they will ingest appropriate calories to maintain caloric balance (eucaloric + sedentary). By doing this the investigators are also able to investigate the effect of acute caloric perturbations on insulin sensitivity, because it is possible that the enhanced insulin sensitivity evident after exercise, as compared to the sedentary state, is due to caloric deficit and not the exercise bout, per se.

Conditions

• Obesity

Interventions

OTHER

Exercise - caloric balance

90 min exercise on Day 1 with meals afterward resulting in caloric balance for the day (i.e.; extra kcals provided to account for energy expended during exercise)\]

OTHER

No Exercise - hyper-caloric diet

Subjects remain sedentary on Day 1 and they ingest meals that are identical to those ingested on the day they performed exercise (i.e.; more calories ingested than expended because no exercise performed).

OTHER

No exercise - caloric balance

Subjects remain sedentary on Day 1 and they ingest a similar proportion of macronutrients however, the total calories ingested will be lower than the other two trials, resulting in caloric balance for the day.

Sponsors & Collaborators

• University of Michigan

  lead OTHER

Principal Investigators

• Jeffrey F Horowitz, Ph.D. · University of Michigan

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

NONE

Model

SINGLE_GROUP

Eligibility

Min Age

18 Years

Max Age

45 Years

Sex

FEMALE

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2003-08-31

Primary Completion

2011-04-30

Completion

2011-04-30

Countries

• United States

Study Locations