Fat Distribution: Health risks and adaptations to exercise Paul Vanderburgh HSS 306: Human Physiology

Agenda  Background  Basic Physiology  Measurement  Links to Disease  Adaptation to Exercise  Summary and Conclusions

Background  %Body Fat: Fat mass/Total mass  BMI: Kg/Ht 2  WHR: Waist-to-Hip Ratio

Basic Somatotypes

Basic Physiology  Insulin Sensitivity: the higher the better  Insulin Resistance: the lower the better  Lipolysis: (the breakdown of fat cells for metabolism) Higher in abdominal than peripheral, deep than subcutaneous (Smith ‘85, Bjorntorp ‘89)

Gender and Fat Distribution Women: Have 50% more fat cells than men, mostly in the periphery Tend to store fat peripherally more than men (Bouchard ’88, Campaigne ’90, Carr ’04) Spare gluteo-femoral (peripheral) fat except during menopause and lactation (Campaigne ’90, Lanska ’85, Carr ‘04) Show more abdominal fat deposition after menopause (Lanska ’85, Fajardo ’04)

Gender and Fat Distribution (cont.) Men: With similar levels of total fatness, show higher:  Fasting glucose levels  TG’s  BP And women with male fat patterning (android) show similar risk factors (Krotkiewski ’86)

Genetics and Fat Distribution  Heredity accounts for 20-25% of fat patterning in central vs. peripheral (Bouchard ’85)  Twins exercise study indicates similar change among twins but different changes between pairs of twins (Despres ‘84)  Same with increased feeding (Poehlman ’86)

Direct Measurement Direct Measurements CT: Computed Tomography MRI: Magnetic Resonance Imaging Expensive and time-consuming: For research purposes only

Field Measurement  WHR: Waist-to-hip ratio  WC: Waist circumference  WHtR: Waist-to-height ratio  T/E: Trunk to extremity skinfold ratio All have shown better predictive quality for CHD and/or metabolic disease risk factors than %fat (Tulloch ’04, Wat ’01, Despres ’01)

WHR Danger Zones Women: Men: 1.0+ (Bjorntorp ’89)

Fat Distribution and Links to Metabolic Disease and CHD Risk Factors  Insulin resistance  Hyperinsulinemia  Impaired glucose tolerance  Diabetes  Hypertension  Low HDL cholesterol (Woods ’89, Lundgren ’89, Boyko ’96, Albu ’97, Bonora ’00, and Wat ’01, lzadeh ’04, Mannucci ‘04)

Adaptations to Exercise  Krotkiewski ’86: Men and android women (WHR>0.82) gained lean mass and reduced %BF Gynoid women did not reduce %BF  Despres ’85: Exercise alters abdominal fat more readily than peripheral  Tremblay ’90: Exercise intensity was directly proportional to abdominal fat loss

Summary  Fat distribution (FD) is a better indicator of metabolic and/or CHD risk than %fat  FD is easily measured by WHR or T/E skinfold ratio  Men are more android, women more gynoid  Android fat easier to lose via exercise than gynoid  Premenopausal women tend to spare peripheral fat even with exercise

Conclusions  Clinicians, teachers, and health professionals should be aware of the diagnostic value of the WHR and its relationship to metabolic and/or CHD outcomes  WHR’s above 0.80 for women and 1.0 for men should be considered indicative of elevated risk for such diseases

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