You feel awake and alert. Caffeine binds to receptors in brain cells, blocking the sleep-inducing effect of adenosine and speeding neural activity. But it's not a substitute for sleep.
Coffee can enhance some headache relievers. Caffeine aids in their absorption and can lead to constriction of blood vessels, which can temporarily widen during a migraine.
By blocking adenosine, caffeine may prevent your arteries from widening; the result is a brief though not necessarily harmful bump in blood pressure.
If you're caffeine sensitive, you get jitters. Caffeine fires the fight-or-flight hormone, adrenaline.
Caffeine restricts the activity of an enzyme that puts the breaks on heat production. As a result, your body produces more heat, which may help you burn calories.
People in an Australian study who were given caffeine and essential amino acids (EAAs) reported feeling less fatigued after sprinting than people who were, given EAAs alone.
Caffeine stimulates your GI tract, helping you poop. It also release bile acids into the intestine, producing a laxative effect as well as the urge to go, like, right now.
Watch Your Caffeine Dosage
- 95 mg-The caffeine in about 8 ounces of coffee. Mugs can range from 8 to 12 ounces.
- 300 mg-About 24 ounces of coffee is the average daily caffeine consumption of a U.S. adult.
- 400 mg-About 32 ounces of coffee is the caffeine threshold you should not exceed in a day.
- 500 mg to 600 mg-About 40 to 48 ounces of coffee is a potent does that may cause rapid heartbeat, insomnia, and tremors.
- 5g to 50g-400 to 4,000 ounces of coffee, is the amount that could actually kill you. Death is rare but has occurred.