Hyperhydrosis or excessive sweating affects 3 of the population and is caused by over activity of the sympathetic nervous system it can be stimulated by stress hormones heat physical activity and exercise and is often hereditary normal sweating is essential to regulate our body temperature for hyperhidrosis sufferers sweating can become uncontrollable and embarrassing impacting negatively on psychological and emotional wellbeing the most common problem area is underarm sweating axi