Yes, up to a point humans actually need stress. Without any challenge or difficulty in our lives we just switch off or give up trying.

However, it's not as simple as that because, of course, it all depends on how much stress you mean. This is different for everybody. Some people love to feel under pressure, and find they act faster and make better decisions when there is a lot at stake. Others need a very calm environment and plenty of time to think; putting pressure on them just causes them to panic and make mistakes. So response to stress is very individual.

For everyone, there is certainly such a thing as too much stress. However, driven, active or confident you are, if you are overstretched, over-challenged or just simply working too hard, you are liable to develop symptoms of stress - you can see a list of these here.