Surprising Things Happen When You Drink A Cup Of Coffee

3. Fight Or Flight

Bad-coffee
Image source: bilmoore.com

As the brain’s cells fire more rapidly, the pituitary gland notices the increased activity and reacts as if it were an emergency. It releases hormones telling the adrenal glands to produce adrenaline. This leads to the “fight or flight” syndrome which causes your pupils to dilate, your heart rate to increase and your blood pressure to jump a little (since the blood vessels are constricted). It also causes your muscles to tense and breathing tubes to open wider, allowing you to breathe easier. These effects occur about 20-30 minutes after drinking.