syndrome x - university of michigankcourses/f99/mvs443/syndromex/syndromex.pdf · exercise...
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Syndrome X
Endocrine and metabolicconsequences of obesity
What is obesity?
n BMI greater than 30 kg/m2
n Incidence greater than 30% of populationand growing in size
Obesity as a consequence of
n Excessive foodintake
n Inappropriatefood choices
Obesity as a consequence of
n Inadequatephysicalactivity
n Hormonaleffects
n Bioenergeticeffects
Health risks of obesity in men
n Arthritisn Diabetesn Hypertensionn Gall stones
Health risks of obesity in women
n Arthritisn Diabetesn Hypertensionn Cancern Gall stones
Inactivity and CHD risk
Health risks of obesity
n depend on fatpatterning
n android (“apple”) hashigher risks
n gynoid (“pear”) haslower risks
Android pattern of obesity
Gynoid pattern of obesity
Android obesity and insulinresistance
n Reducedglucosetolerance
Android obesity and insulinresistance
n Insulinoversecretion
Android obesity and insulinresistance
n Reducedglucoseutilization
Android obesity and insulinresistance
n Reducedglucoseutilization
Android obesity and insulinresistance
n Reducedglucosemetabolism
Android obesity and insulinresistance
n Reducedcapacity ofinsulin tosuppresshepaticglucoseproduction
Android obesity and insulindefectsn Insulin
oversecretion isa function ofobesityindependentlyof its pattern
Android obesity and insulindefectsn Insulin
clearance isreduced
Insulin oversecretion and resistancein aging
n Aging is oftenasociated with obesity
n Reduced insulin-induced glucoseuptake is seen both inaged and obese
n This is due to reducedperipheral sensitivityto insulin, principallyin the muscle
Insulin oversecretion andresistance in aging
n Aging is oftenasociated with obesity
n Oversecretion ofinsulin is seen in bothaged and obese
n High fasting plasmainsulin
Insulin defect acts on portalvascular bedn Insulin
concentration ishigh in theportalcirculation dueto insulinoversecretion
Insulin defect acts on portalvascular bedn High insulin acts on
the visceral adiposetissue causingincreased visceraladiposity
Insulin resistance of androidobesen Resides in skeletal musclen Muscle is insensitive to insulin
Insulin resistance of muscles inthe android obesen Deficient
glucoseuptake
n Deficientglycogensynthesis
Insulin resistance affects lipidmetabolismn Adipose LPL
hypoactivebecauseadiposetissue isinsulinresistant
n Lower LDLreceptorbinding
Development of syndrome X
n Peripheralinsulinresistance
n Insulinoversecretion
n More insulinresistance
Role of androgens in androidobesityn Reduced levels of
SHBG, the high-affinity bindingprotein for androgens
Role of androgens in androidobesityn Reduced levels of
SHBG, the high-affinity bindingprotein for androgens
n Increased freeandrogen titers
Exercise counteracts syndrome x
n Fat lossn Increased insulin sensitivityn Reduced blood pressuren Reduced plasma lipids
Exercise and increased insulinsensitivityn Acute increase in
sensitivityn Associated with
glycogendepletion,increased GLUT-4and glucose uptake
Exercise and reduced plasmalipids
Android obesity and muscle fibertypesn Higher
proportionsof fastanaerobicfibers
n Trainingincreasesconversionto red fibers
Endurance training counteracts
n obesity
Endurance training counteracts
n hyper-tension
Endurance training counteracts
n plasmalipids
Endurance training counteracts
n glucoseintolerance
Endurance training improves
n glucosedisposal
Obesity
n Major health problemn Results from inappropriate life-style choicesn Can be reduced and its risks attentuated
with aerobic exercise and better dietarychoices