The body's response to danger is the release of adrenaline which produces " the alarm reaction ".
It's not difficult to recognise and learn to control the alarm reaction of stage fright. But the off-stage pressures of being a professional singer can easily turn this into a way of life.
Be aware of the stresses of looking for work, constantly travelling, living in hotel rooms, encountering new people, long delays at airports, moving through time zones, dealing with bad reviews, lack of security, professional rivalry, disrupted relationships........
Living with a constant adrenaline rush can lead to black-outs, ulcers and hardening of the arteries.