Inclusion Criteria

• Apparently healthy men and women, employed at Mayo Clinic
• Between the ages of 18 and 75
• Must be able to walk continuously for 2 miles or 1 hour at a moderate pace and free of any orthopedic problems that would limit walking
• Patients with three or more risk factors, as defined by the American College of Sports Medicine (ACSM), must receive clearance from their primary care physician before participating in this study. ACSM risk factors include
  • Age (men ≥ 45 years of age and women ≥ 55 years of age)
  • Family history (heart attack, bypass surgery, or sudden death before the age of 55 years for father/brother; or before 65 years old for mother/sister)
  • Smoking status (current smoker, or have quit < 6 months, or is exposed to environmental smoke)
  • Sedentary lifestyle (not participating in moderate physical activity at least 3 days/week for 3 months)
  • Obesity (body mass index ≥ 30kg/m2 or waist girth > 102 cm for men and 88 cm for women)
  • Hypertension (systolic blood pressure ≥ 140 mmHg and/or diastolic blood pressure ≥ 90 mmHg, or currently taking blood pressure medication)
  • Dyslipidemia (LDL ≥ 130 mg/dl, or HDL < 40 mg/dl, total cholesterol ≥ 200 mg/dl or taking medication)
  • Pre-diabetes (IFG ≥ 100 mg/dl or OGTT ≥ 140 and ≤ 199 mg/dl confirmed by two different measurements)
• Ability to understand study procedures and to comply with them for the entire length of the study

Exclusion Criteria

• Individuals with known orthopedic problems that would prevent them from walking continuously for more than 30 minutes
• Women who are pregnant or plan to become pregnant will not be eligible to participate in the study
• Individuals with absolute contraindications to exercise testing, as defined by the ACSM. These include
  • recent significant change in resting ECG suggesting significant ischemia
  • recent myocardial infarction (within 2 days) or other acute cardiac event
  • unstable angina
  • uncontrolled cardiac dysrhythmias causing symptoms or hemodynamic compromise
  • symptomatic severe aortic stenosis
  • uncontrolled symptomatic heart failure
  • acute pulmonary embolus or pulmonary infarction
  • acute myocarditis or pericarditis
  • suspected or known dissecting aneurysm
  • acute systemic infection, accompanied by fever, body aches, or swollen lymph glands
• Individuals exhibiting signs and symptoms indicative of cardiovascular disease, as defined by the ACSM, will not be included in this research study. Signs and symptoms include
  • Pain/discomfort in the chest, neck, jaw, arms, or other areas that may result from ischemia
  • Shortness of breath at rest or with mild exertion
  • Dizziness or syncope
  • Orthopnea or paroxysmal nocturnal dyspnea
  • Ankle edema
  • Palpitations or tachycardia
  • Intermittent claudication
  • Known heart murmur
  • Unusual fatigue or shortness of breath with usual activities
• Anyone under the age of 18
• Inability or unwillingness of individual or legal guardian/representative to give written informed consent