Effect of Exercise Training Intensity on Abdominal Visceral Fat and Body Composition

Brian A. Irving; Christopher K. Davis; David W. Brock; Judy Y. Weltman; Damon Swift; Eugene J. Barrett; Glenn A. Gaesser; Arthur Weltman

Disclosures

Med Sci Sports Exerc. 2008;40(11):1863-1872. 

In This Article

Abstract and Introduction

Abstract

The metabolic syndrome is a complex clustering of metabolic defects associated with physical inactivity, abdominal adiposity, and aging.
Purpose: To examine the effects of exercise training intensity on abdominal visceral fat (AVF) and body composition in obese women with the metabolic syndrome.
Methods: Twenty-seven middle-aged obese women (mean ± SD; age = 51 ± 9yr and body mass index = 34 ± 6 kg·m-2) with the metabolic syndrome completed one of three 16-wk aerobic exercise interventions: (i) no-exercise training (Control): seven participants maintained their existing levels of physical activity; (ii) low-intensity exercise training (LIET): 11 participants exercised 5 d·wk-1 at an intensity ≤ lactate threshold (LT); and (iii) high-intensity exercise training (HIET): nineparticipants exercised 3 d·wk-1 at an intensity > LT and 2 d·wk-1 ≤ LT. Exercise time was adjusted to maintain caloric expenditure (400 kcal per session). Single-slice computed tomography scans obtained at the L4-L5 disc space and midthigh were used to determine abdominal fat and thigh muscle cross-sectional areas. Percent body fat was assessed by air displacement plethysmography.
Results: HIET significantly reduced total abdominal fat (P < 0.001), abdominal subcutaneous fat (P = 0.034), and AVF (P = 0.010). There were no significant changes observed in any of these parameters within the Control or the LIET conditions.
Conclusions: The present data indicate that body composition changes are affected by the intensity of exercise training with HIET more effectively for reducing total abdominal fat, subcutaneous abdominal fat, and AVF in obese women with the metabolic syndrome.

Introduction

The metabolic syndrome is a complex clustering of cardiometabolic abnormalities associated with aging, physical inactivity, and abdominal adiposity.[5,12,18] Globally, the incidence of the metabolic syndrome and its associated increase in cardiometabolic risk have reached pandemic proportions. Of the risk factors used to identify the metabolic syndrome, elevated abdominal visceral fat (AVF) has consistently been shown to be associated with increased cardiometabolic risk.[30] The International Diabetes Federation (IDF) consensus statement[2] identified central obesity as the unifying cardiometabolic risk factor among individuals with the metabolic syndrome. Researchers and clinicians worldwide are intensively investigating both pharmacological and nonpharmacological approaches to reduce visceral adiposity and its related comorbidities.

Exercise training provides an economically viable, nonpharmacological approach for eliciting beneficial adaptations in body composition and cardiometabolic risk. In support of this contention, endurance training has been shown to be a powerful strategy for inducing abdominal fat loss, particularly with respect to AVF loss.[16,23,27,31] Despite much interest in exercise-induced fat loss, the optimal exercise prescription to maximize fat loss remains elusive. Only a limited number of exercise interventions have systematically examined the impact of endurance training intensity on fat loss and, in particular, AVF loss under equivalent energy expenditures.[36,37] It may be postulated that high-intensity exercise training (HIET) may induce greater fat loss, in particular, AVF loss, than low-intensity exercise training (LIET) for several reasons. First, HIET induces secretion of lipolytic hormones, including growth hormone and epinephrine,[32,33] which may facilitate greater postexercise energy expenditure and fat oxidation. Second, it has been reported that under equivalent levels of energy expenditure, HIET favors a greater negative energy balance compared with LIET.[21] In the present study, we examined the impact of endurance training intensity on AVF under equivalent caloric expenditure (2000 kcal·wk-1). We hypothesized that 16 wk of endurance training above the lactate threshold (LT; i.e., HIET) would result in a greater reduction in AVF and more favorable changes in body composition than 16 wk of endurance training below the LT (i.e., LIET) in abdominally obese women with the metabolic syndrome.

Comments

3090D553-9492-4563-8681-AD288FA52ACE
Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.
Post as:

processing....