For many people a trip to the GP can be an extremely stressful event. This in turn may artificially raise their blood pressure and result in unnecessary drug treatment for this condition. But now a small portable device is likely to lead to radical changes in the way doctors diagnose high blood pressure. The ambulatory blood pressure monitor is worn by the patient over a 24 hour period. Every 30 minutes it measures and records the blood pressure while the person goes about their normal daily life. it is estimated that with this device up to a third of patients may be spared unnecessary blood pressure treatment.