Biofeedback is a technique that measures bodily functions and gives you information about them in order to help train you to control them.

Biofeedback is most often based on measurements of:

• Blood pressure
• Brain waves (EEG)
• Breathing
• Heart rate
• Muscle tension
• Skin conductivity of electricity
• Skin temperature

By watching these measurements, you can learn how to alter these functions by relaxing or by holding pleasant images in your mind.

Electrodes measure your heart rate, blood pressure, or other function. A monitor displays the results for both you and the trained practitioner to see. A tone or other sound may be used to let you know when you've reached a goal or certain state.

While the practitioner describes stressful situations and guides you through relaxation techniques, you can see how your heart rate and blood pressure change in response to being stressed or remaining relaxed.

Biofeedback teaches you how to control and change these bodily functions. By doing so, you feel more relaxed and may be able to help treat such conditions as:

• Anxiety and insomnia (how well biofeedback works for these symptoms remains controversial)
• Tension and migraine headaches
• Urinary incontinence

Burgio KL, Kraus SR, Menefee S, Borello-France D, Corton M, Johnson HW, et al. Behavioral therapy to enable women with urge incontinence to discontinue drug treatment: a randomized trial. Ann Intern Med. 2008;149(3):161-9.

Loder E, Rozzoli P. Tension-type headache. BMJ. 2008;336(7635):88-92.

Nestoriuc Y, Martin A. Efficacy of biofeedback for migraine: a meta-analysis. Pain. 2007;128(1-2):111-27. Epub 2006 Nov 2.

Rogers RG. Clinical practice. Urinary stress incontinence in women. N Engl J Med.2008;358(10):1029-1036.