Why do type A personalities get stressed?

Type A's have a hard time relaxing and as a result they are more likely to get stressed than others. Even during a break a type A would be thinking about work and what he or she should be doing.

Even if they are doing an activity that they like, Type A's usually keep on monitoring the time. This can make them stressed, (See also why some people procrastinate).

Type A's hardly give up on the tasks they have to do. Even if they are too busy, they still insist on finishing everything they planned to finish.

Because Type A's schedule is always full, they don't have any tolerance for unexpected events that waste time. That's why they get very stressed when such an event happens.

Type A's are very competitive, and this behavior can lead to much more stress.

Type A's can hardly wait for anything and because of their impatient habit they can get too stressed if they are forced to wait. (See why some people are impatient).

Because Type A's usually don't take a day off, they are more subject to stress than other people who take vacations and some days off.

Type A personalities always race against time. They always compare their progress to time to see how much they achieved. This usually makes them very stressed.

Type A's usually stuff their day with a big to-do list that in many cases can be completed in a single day. Type A's like to achieve more and sometimes they overload their day with so many things.