Effect of Iyengar yoga practice on fatigue and diurnal salivary cortisol concentration in breast cancer survivors

Abstract

To examine the effect of regular Iyengar yoga practice on measures of self-perceived psychosocial function and diurnal salivary cortisol secretion in stage II-IV breast cancer survivors (n = 18). Women were randomly assigned to attend yoga practice for 90 min twice weekly for 8 weeks (n = 9) or to a wait-listed, noninterventional control group (n = 9). Traditional Iyengar yoga routines that progressively increased in difficulty as participants gained strength and flexibility were used. At baseline and after the 8-week study period, women completed self-report instruments to document various aspects of psychosocial and physical functioning, and collected salivary samples for cortisol analysis four times during the day for two consecutive days. The yoga group had lower morning and 5 p.m. salivary cortisol and improved emotional well-being and fatigue scores. Breast cancer survivors are at risk for chronic psychosocial distress that may alter activity of the hypothalamic-pituitary-adrenal axis, resulting in aberrant regulation of cortisol secretion and increased risk of immune dysfunction and cancer progression. Regular yoga practice may be a low-risk, cost-effective way to improve psychosocial functioning, fatigue, and regulation of cortisol secretion in breast cancer survivors. These findings require validation with a larger randomized study.