An introvert, because she likes to keep to herself.
If you are exercising in your target fitness zone, you are between your threshold of training and your target ceiling.
If you achieve a good fitness rating, you probably are at the level of fitness needed to live a full, healthy life.
These are what I found on Quizlet.
It depends on what causing it. the only thing I can say is to drink plenty of fluids but I would recommend to go see a doctor, if you are unsure or worried.
cardiovascular fitness activities