Effect of Yoga on Objective and Subjective Menopausal Hot Flashes

Hot flashes and/or night sweats are the most common and troubling symptoms associated with menopause. It is estimated that 64% to 87% of women report experiencing hot flashes for an average of about 4 years. For many women, these symptoms are frequent and severe enough to become debilitating and interfere with daily activities. They often occur at night, disturbing sleep and leading to daytime irritability, fatigue and depressed mood. About 30-40% of menopausal women seek medical help for hot flashes. Relief from hot flashes has been shown to be the primary reason that women initiate hormone therapy (HT).

HT is currently the gold standard for treatment of vasomotor symptoms. A Cochrane Database systematic review showed a 75% reduction in hot flash frequency with hormone therapy compared to placebo.1 However, recent findings from the Women's Health Initiative (WHI) trial indicate that benefits of HT are outweighed by risks, such as coronary heart disease, stroke, pulmonary embolism, breast cancer, and probable dementia. The wide publicity of the WHI results has heightened women's concerns about taking HT and many women have sought alternative treatments for hot flashes. These alternatives include other pharmaceutical agents, herbal or dietary remedies, and behavioral therapies. Unfortunately, many of these agents have a high incidence of side effects or have not been shown to be effective. A recent NIH conference has called for more research on alternative treatments for hot flashes.

Behavioral interventions involving relaxation and slow deep, abdominal breathing have been found to be useful for reducing mild- to moderate-intensity hot flashes. Although the physiological mechanisms for the effectiveness of these interventions are not completely understood, there is some suggestion that they may help reduce sympathetic activity which is related to the narrowing of the thermoneutral zone. It is currently thought that hot flashes are linked to a disruption in thermoregulation and that elevated levels of brain norepinephrine may be the primary mechanism for altered thermoregulation. Breathing techniques form the most integral core of any yoga practice which involves the combination of physical postures (asanas), breathing (pranayama), and deep relaxation (savasana). Despite suggestions that yoga may be beneficial for the relief of hot flashes, these potential benefits have not been well-studied.

To date, treatment efficacy for hot flashes has been limited to self-reported, subjective symptoms. While subjective hot flashes are important from a woman's perspective in her decision-making with respect to treatment, research has shown that they can be influenced by mood and reporting biases. Objective measures are not subject to these biases and have the advantage of providing insight as to whether an intervention has a physiological effect. However, until recently, reliable objective measures that could be used in an ambulatory setting were not available. NCCAM has recently funded the development of new technologies to monitor objective hot flashes in an ambulatory setting, as measured by skin conductance. This technology greatly enhances our ability to fully evaluate the impact of treatment on both subjective and objective hot flashes.

The primary goal of this R21 pilot grant is to obtain preliminary data on the efficacy of Integral Yoga for reducing self-reported menopausal hot flashes. Secondary aims are to determine the impact of yoga on objective hot flashes and other outcomes and study feasibility. Our primary hypothesis will be a greater reduction in subjective hot flash frequency and severity in the yoga group than in two control groups. Secondary outcomes will include a greater reduction in objective hot flash frequency; a greater decrease in hot flash interference; and greater improvement in sleep, other symptoms, mood, perceived stress, and overall quality of life in the yoga group.