- Dopamine: To some extent we're all chasing this pleasure chemical, you can get it from eating or from exercise.
- Growth Hormones (Human Growth Hormone): These guys help regulate and make muscle. The growth factors such as hepatocyte, insulin, and fibroblast go to muscles/repair following a workout.
- Estrogen: Levels of this hormone correlate whether you burn fat (higher levels typically in women) or carbs (usually in men).
- Endorphins: These come from the pituitary gland at the base of the brain. Endorphins block pain and make one feel happy. Note 'the runner's high'.
If you're looking for additional detailed information, here is a great PowerPoint presentation from the University of South Carolina Aiken.