Caffeine is a stimulant. This can cause your nervous system to become hyper-aware; which in turn can cause an increase in your stress level. Caffeine causes a rise in both respiration and cardiac function. The hormone adrenaline is secreted by the adrenal glands in response to stimulation of the sympathetic nervous system. It causes what is known as the "fight-or-flight" response.
A woman's fist is aproxomently one serving size for her
The cocktail party effect. The cocktail party effect is the phenomenon of the brain's ability to focus one's auditory attention on a particular stimulus while filtering out a range of other stimuli, as when a partygoer can focus on a single conversation in a noisy room.
