This randomized controlled trial will compare the effectiveness of an Iyengar Yoga intervention to a Wellness Seminar health education lecture series, for improvements in energy, mood and biological functioning in breast cancer survivors with persistent, post-treatment fatigue. It is anticipated that the Iyengar Yoga intervention will be feasible and acceptable to breast cancer survivors with minimal side effects and that the Yoga intervention will be effective in improving fatigue and physical performance.

Fatigue is the most common and distressing side effect of cancer treatment and persists beyond successful treatment completion in approximately 30% of breast cancer survivors, causing serious disruption in quality of life. Behavioral interventions incorporating physical activity or relaxation/stress management have demonstrated beneficial effects on cancer-related fatigue, although research in cancer survivors is limited. Mind-body interventions such as yoga are extremely popular among cancer patients and offer a promising alternative to traditional treatments. Research is needed to establish the feasibility and efficacy of these interventions in cancer populations, particularly those who are experiencing problems with fatigue.

Inclusion Criteria:

• Diagnosed with early, resectable breast cancer (Stage I or II)
• Completed treatment with surgery, radiation, and/or chemotherapy between 6 months and 5 years previously
• No other cancer in last 5 years, including breast cancer recurrence
• Postmenopausal women
• Age 40 - 65
• Reporting persistent cancer-related fatigue

Exclusion Criteria:

• Evidence that fatigue is directly related to a medical or psychiatric disorder (e.g., untreated hypothyroidism, diabetes, anemia (defined as hematocrit < 24), chronic fatigue syndrome, current major depression, insomnia, sleep apnea, restless leg syndrome)
• Evidence that fatigue is related to other non-cancer related factors (e.g., shift work, recent change in activity or schedule)
• Physical problems or conditions that could make yoga unsafe (e.g., serious neck injuries, unstable joints; also severe cachexia, dizziness, bone pain, severe nausea, etc)
• Regular use of medications and/or behavioral therapies that would confound evaluation of IY, including regular participation in yoga classes
• Presence of medical conditions that involve the immune system and would confound immune evaluation (e.g., autoimmune disorder, inflammatory disease)
• Use of medications that might confound immune evaluation (e.g., regular use of corticosteroids, narcotics, opiates)
• Unable to commit to intervention schedule
• Body mass index greater than 30 kg/m2
• Regular tobacco (defined as daily or near daily) or alcohol use (defined as > 2 drinks/day)