 Previously it has been demonstrated that exposing the heart to electromagnetic field during exercise stress test improves the recovery following the stress test. This is explained by the effect of the electromagnetic field on the sympathetic activity of the heart. In the present study we would like to further investigate the effects of electromagnetic field on autonomic nervous system function in patients with chronic musculoskeletal pain that usually have high sympathetic activity. Each patient will be exposed to 20 minutes of electromagnetic field during which the autonomic nervous system function will be measured. In addition, patient tolerability to the exposed magnetic field will be investigated. We assume that short exposure to electromagnetic field would result in decreased sympathetic activity and therefore, on the long run, could be suggested as a therapeutic tool for such patients. 