• Serum estrone concentrations as measured by radioimmunoassay at 12 months [ Designated as safety issue: No ]
  

• Serum estradiol and free estradiol concentration as measured by radioimmunoassay at 12 months [ Designated as safety issue: No ]
  
• Testosterone and free testosterone as measured at 12 months [ Designated as safety issue: No ]
  
• Sex hormone binding globulin as measured at 12 months [ Designated as safety issue: No ]
  
• Insulin and insulin-like growth factor (IGF)-1 as measured at 12 months [ Designated as safety issue: No ]
  
• IGF binding protein-3 as measured at 12 months [ Designated as safety issue: No ]
  
• Mammographic density (i.e., percentage density and dense area) as measured at 12 months [ Designated as safety issue: No ]
  
• Weight and body mass index as measured at 12 months [ Designated as safety issue: No ]
  
• Total and percentage body fat and body fat distribution (i.e., waist and hip circumferences) as measured by dual x-ray absorptiometry at 12 months [ Designated as safety issue: No ]
  
• Quality of life as measured at baseline, 6 months, and 12 months [ Designated as safety issue: No ]
  
• Change in daily caloric intake as measured by Food Frequency Questionnaire at baseline, 6 months, and 12 months [ Designated as safety issue: No ]
  

DISEASE CHARACTERISTICS:

• At increased risk for developing breast cancer due to any of the following lifestyle risk factors:

  • Lack of physical activity
  • Excess weight
  • Obesity
  • Weight gain over lifetime
• Body mass index > 25.0
• Physically able to undertake a moderate exercise or calorie reduction program
• No history of invasive or in situ breast cancer

PATIENT CHARACTERISTICS:

• Postmenopausal, defined by the absence of periods for the past 12 months
• Able to attend study clinic visits and classes, and undergo study measurements
• Able to fill out questionnaires and logs in English
• No moderate to high alcohol intake (more than 2 drinks per day)
• No concurrent smoking
• No invasive cancer within the past 10 years except simple basal cell or squamous cell carcinoma

• No diabetes mellitus

  • Fasting blood sugar < 126 mg/dL (on 2 occasions)
• Hematocrit 32-48%
• WBC 3,000-15,000/mm³
• Potassium 3.5-5.0 mEq/L
• Creatinine ≤ 2.0 mg/dL
• No abnormalities on screening physical that contraindicate study participation

• No contraindications for treadmill testing or entry into a training program, including any of the following:

  • Myocardial infarction within the past 6 months
  • Pulmonary edema
  • Myocarditis
  • Pericarditis
  • Unstable angina
  • Pulmonary embolism or deep vein thrombosis
  • Uncontrolled hypertension (i.e., blood pressure > 200/100 mm Hg)
  • Orthostatic hypotension
  • Moderate-to-severe aortic stenosis
  • Uncontrolled arrhythmia
  • Uncontrolled congestive heart failure
  • Third-degree heart block
  • Left bundle branch block
  • Thrombophlebitis
  • ST depression > 3 mm at rest
  • History of cardiac arrest or stroke

• Normal exercise treadmill testing (ETT)

  • Negative thallium or echo ETT required for patients with abnormal ETT (defined as ≥ 1.5 mm ST depression in > 1 lead within 1-minute recovery OR ≥ 1.1 mm ST depression in > 1 lead after 1-minute recovery OR reading of positive test by study doctor)
• No drug abuse
• No significant mental illness

PRIOR CONCURRENT THERAPY:

• More than 6 months since prior and no concurrent menopausal hormone replacement therapy of any type, including vaginal route
• No concurrent participation in any other organized weight loss or exercise program
• No concurrent appetite suppressant medication
• No concurrent medications (e.g., weight-loss medications) likely to interfere with adherence to interventions or study outcomes