According to the NHS,
"Stress is the feeling of being under too much mental or emotional pressure.
"Pressure turns into stress when you feel unable to cope. People have different ways of reacting to stress, so a situation that feels stressful to one person may be motivating to someone else.
"Many of life’s demands can cause stress, particularly work, relationships and money problems. And, when you feel stressed, it can get in the way of sorting out these demands, or can even affect everything you do.
"Stress can affect how you feel, think, behave and how your body works. In fact, common signs of stress include sleeping problems, sweating, loss of appetite and difficulty concentrating.
"You may feel anxious, irritable or low in self-esteem, and you may have racing thoughts, worry constantly or go over things in your head. You may notice that you lose your temper more easily, drink more or act unreasonably.
"You may also experience muscle tension or pain, or dizziness.
"Stress causes a surge of hormones in your body. These stress hormones are released to enable you to deal with pressures or threats – the so-called "fight or flight" response.
"Once the pressure or threat has passed, your stress hormone levels will usually return to normal. However, if you're constantly under stress, these hormones will remain in your body, leading to the symptoms of stress."
The descriptions of stress in autism would seem to indicate that it is much more common that in the general population and that there may be important differences in the physiology of stress in autism. It would appear to be much more severe and long term and the consequences more disabling. Results of stress impact on all areas of life, health and wellbeing and behaviour. The stress affecting care givers is also reported as more common and severe than in other groups.