obesity presented by kristen billings. what is obesity? surplus of adipose tissue-containing fat...
TRANSCRIPT
ObesityPresented by Kristen Billings
What is Obesity?
Surplus of adipose tissue-containing fat stored in triglyceride form
Characterized by excess body weight Overweight is defined as deviation in body weight from
some standard or “ideal” weight related to height. Body weight is a function of energy balance over an
extended period of time Overweight does not always reflect obesity
The point at which excessive fat constitutes obesity is arbitrary
Epidemiology
Accessible, abundant, and inexpensive energy-dense foods among industrialized countries
Substantial reduction in average daily energy expenditure required for survival.
Evolutionary adaptation theory
More than two decades of steadily increasing rates of obesity Since the end of 2006 the rates have appeared to stabilize
Epidemiology
66% are overweight, 5% extremely obese
18% of children are overweight
In 2006- 33.3% of adult men and 35.3% women in U.S were categorized as obese (BMI > 30) Notably higher raters of obesity were seen in Hispanic and
non-Hispanic black women.
Cost
Obesity related conditions account for 7% of total healthcare costs in the U.S. Direct and indirect costs of obesity are in excess of $117
billion annually
Symptoms
BMI (weight in kg/height squared in meters): Class I 30.0-34.9 Class II 35.0-39.9 Class III >40.0
Excessive accumulation of body fat Women >35% Men >25%
Diagnosis
Body Mass Index
Waist Circumference
Body Fat Percentages
Waist to hip ratio
Complications
Associated with numerous comorbidities, many of which are life threatening
Increases the overall risk and severity of numerous diseases
Altered physiological responses: increased fasting insulin, increased insulin response to glucose, decreased insulin sensitivity, decreased growth hormone, decreased growth hormone response to insulin stimulation, increased adrenocortical hormones, increased cholesterol synthesis and excretion, decreased hormone-sensitive lipase
Complications
Distribution of fat is of more importance for risk of disease than total fat alone
Upper body fat distribution (android obesity): strongly correlated with increased risk of coronary artery disease, hypertension, hyperlipidemia, diabetes, hormone and menstrual dysfunction
Complications
Chronic Diseases Diabetes Hypertension Hypercholesterolemia Hyperinsulinemia Hypertriglyceridemia
Increased risk of cardiovascular disease
Treatment
Primary objective of obesity management is to reduce fat weight while preserving lean body weight
Behavioral change focused on dietary and activity habits toward weight reduction
FDA approved drugs
FDA approved invasive procedures
Treatment- Behavioral Change
Patients are less motivated by health and more by personal appearance
Success in weight loss is more commonly seen when: Person is slightly or moderately obese Has upper body fat distribution Doesn’t have a history of weight cycling Sincere desire to lose weight Became overweight as an adult
Treatment- Drugs
Drug Mechanism of action Exercise-related precautions
Adipex-P Appetite suppressant Increase in blood pressure
Meridia Appetite suppressant Increase in blood pressure
Dexedrine CNS stimulant Possible cardiovascular risks
Alli & Xenical Reduction in fat absorption via inhibition of pancreatic lipase activity in intestine
none
Treatment- Invasive Procedures
Based on reducing the size of stomach and lowering the absorption of nutrients in the intestine
Must have BMI of >40 or >35 with comorbidities such as diabetes and hypertension to be eligible
Surgical treatment of obesity has been shown to reduce excess body weight by an average of 50-60%
Treatment- Invasive Procedures
Laparoscopic gastric banding Minimally invasive surgery Adjustable silicone band is placed around top portion of
stomach Small gastric pouch is created which reduces capacity of
stomach and produces a feeling of fullness shortly after eating
Benefits: minimal surgical trauma and pain, fast recovery rate, rare operative mortality.
Surgery Videos
http://www.youtube.com/watch?v=n-ucSHx9nHM
http://www.youtube.com/watch?v=P83Vs9GQ0WI
Treatment- Invasive Procedures
Roux-en-Y gastric bypass Invasive surgical procedure that reduces capacity of the
stomach A small pouch is created at the top of the stomach that is
then connected directly to middle portion of the small intestine
The rest of the stomach and the upper portion of the small intestine are bypassed.
Procedure has a higher mortality and complication risk than the lap-band
Effects of Exercise
Biomechanical Effects
Excess joint stress
Affected movement and gait
Increased foot pressure
Decreased strength
Increased risk of osteoarthritis
http://www.youtube.com/watch?v=cNATWsVVwgo
Effects of Exercise
Comorbidities of obesity (diabetes, hypertension, CAD, sleep apnea, increased overall risk of exercise) may affect the exercise response.
Past experiences/current fears of exercise
Exercise training in combination with caloric restriction reduces body weight and favorably alters body composition. Ineffective in morbidly obese individuals
Benefits of Exercise
Preservation of lean body mass despite caloric restriction
Improved insulin sensitivity
Favorable changes in metabolic rate and lipid profiles
Reduced blood pressure
Improved mood
Possible effects on satiety
Overall reduction in comorbidity risk
Benefits of Exercise
Loss of regional fat
More effective in reducing abdominal fat cell size than diet alone
Energy expenditure following exercise remains elevated above pre-exercise levels
Glucose metabolism Decreased fasting glucose and insulin Increased glucose tolerance Decreased insulin resistance
Exercise Testing
Primary goal: develop a safe and effective exercise program
Low-level protocols are recommended because of the low function capacity of most obese individuals
Testing protocol must take into consideration any comorbidities, orthopedic limitations and current medications.
Arm or leg ergometry may be more appropriate depending on orthopedic limitations and weight limits of treadmills.
Exercise Testing
Initial exercise intensity is most likely far below the point at which cardiac risk is of concern
Exercise testing is used to determine physical work capacity
Special Considerations
Increased risk of orthopedic injury Physical injury may be primary reason for discontinuation
of exercise
Increased risk of cardiovascular disease
Increased risk of heat intolerance
Weight regain averages 33-50% of initial weight loss within 1 year of terminating treatment
Exercise Prescription
Exercise prescription should optimize energy expenditure while maintaining minimal potential for injury
Total energy expenditure should include that of the actual exercise as well as the recovery period
Two or more short sessions/day may be more tolerable and result in same or higher total energy expenditure
Exercise Prescription
ACSM recommends accumulating 200-300 min/week (>2000 kcal/week) of physical activity for weight loss and weight maintenance.
Initial intensity and duration should be low and progression should be gradual: Mode- non-weight-bearing exercise such as: walking,
swimming, biking increase in activities of daily living and resistance training
Frequency-daily or at least 5/week Duration- 200-300 min/wk (30-60 min/day) Intensity- 40-60% of peak oxygen consumption
Exercise Goals
Significant health benefits can be achieved by losing only 10-20% of body weight even if the ideal body weight is not reached
Loss of 1lb/week, -3500 calories/week, -500 calories/day
Loss of 10lbs maintained for 6 months before further weight loss
Summary and Conclusion
Overuse injury prevention
Adequate flexibility, warm-up, cool-down
Gradual progression of intensity and duration
Use of low-impact or non-weight-bearing exercises
Thermoregulation
Neutral temperature and humidity
Cool times of day
Adequate hydration
Loose fitting clothing
References
1.American College of Sports Medicine. 2010. ACSM’s guidelines for exercise testing and prescription, 8th ed. Baltimore: Lippincott Williams & Wilkens, chapter 10.
2.ACSM. 1999. Roundtable Supplement. Physical activity in the prevention and treatment of obesity and its comorbitities. Med. Sci. Sport Exer. 31(11) : S497-S667.
3. American Obesity Association. 2000. http://www.obesity.org/
4.ACSM. 2009. Position Stand. Appropriate physical activity intervention strategies for weight loss and prevention of weight gain for adults. Med. Sci. Sport Exer. 41 :459-467.
5.Rampersaud, E., et al. 2008. Physical activity and the association of the common FTO gene variants with body mass index and obesity. Arch Intern Med. 168(160): 1791-1797.
6. Patricia Curtis. 2007. Fighting Fat New Frontiers. Readers Digest. 85-91