I used to naively think one 'used up' dopamine when one moved. After all you need dopamine to move, but apparently the opposite is true. Any movement, even passive movement (when someone moves your limbs for example), stimulates dopamine production. And it's like a dynamo, the brain needs less stimulation to make dopamine each time, and the follow on effect of 'free dopamine' lasts longer each time. Dopamine can be stimulated by
* being active - walking, dancing, swimming etc
* using facial expressions
* being engaged and attentive
* (and as I mentioned yesterday) nesting for women and mating for men!