1. What is the brain's role in mental health and illness?
2. How does stress affect health?
3. What are the main sources of stress and the
main approaches to managing stress?

1. Most scientists believe that mental illnesses result from problems with the communication between neurons in the brain (neurotransmission). For example, the level of the neurotransmitter serotonin is lower in individuals who have depression. This finding led to the development of certain medications for the illness.

the more fit you are, the faster the recovery. your heart rate drops most sharply in the first minute after you stop exercising; it should then fall about 20 beats a minute—a drop of less than 12 beats a minute is considered abnormal. this “recovery heart rate” is measured as part of an exercise stress test.