Short Term Effects
The coffee pick-me-up (a short term effect)
Many people find that coffee gives them a boost of energy and enhanced attentiveness. Caffeine is indeed a stimulant. Medically, it’s used for heart stimulation and for increasing urine production (a diuretic).
So why do you get the buzz?
Caffeine is chemically very similar to adenosine, a chemical secreted by the brain. Adenosine builds up throughout the day and binds to special receptors in the brain, slowing down nervous activity, dilating blood vessels and causing drowsiness. Like Adenosine, caffeine binds to the same receptors but has the opposite effect. It not only speeds up brain cell activity, it also blocks dilation of the blood vessels, constricting blood vessels of the brain.
The increased nerve cell activity causes the pituitary gland to releases hormones, acting as though the body were facing an emergency. The hormones stimulate the adrenal glands to produce adrenaline, causing:
- Increase in heart rate
- Dilating pupils and airways
- Raising blood pressure by constricting blood vessels close to the surface
- Reducing blood flow to the stomach
- The liver to release sugar into the bloodstream to provide extra energy.
Drinking coffee throughout the day causes the body to be in intermittent ‘fight and flight’ mode.