I'm very tired but don't want to sleep.
user
You can try drinking caffeine. Also make sure you are drinking enough water. When you are dehydrated you can feel drowsy.
assistant
I do not want to drink coffee because I have heart problems. Is there something else that I can do to keep me awake without risking heart problems?
user
Here are some other recommendations:

1. vitamins B may help improve energy levels, however be sure not to take high dose as it may cause some bad side effects.
2. Take a warm shower
3. Try deep breathing or meditation which may improve your sleepy problem
assistant