What are the short-term and long-term effects of caffeine?

Caffeine takes about an hour to affect you (less on an empty stomach), and usually lasts 4-6 hours. Because caffeine is a stimulant, most people experience increased alertness, blood pressure, and breathing rate. These effects are mostly due to caffeine increasing your metabolic rate (though it has not been linked to weight loss). The drug is a diuretic, causing increased urination which can lead to dehydration. Caffeine makes many people feel jittery, “on edge,” and unable to sleep. Long-term use can lead to nervousness, insomnia, dehydration, stomach irritation, and fatigue.

Should I cut back on caffeine?

Assuming you don’t consume a ridiculous amount of caffeine, there’s no reason to cut back unless you experience negative side effects. Caffeine promotes slight bone-density loss, but this can be countered by getting adequate calcium each day (1000 mg). The average person consumes about 200 milligrams of caffeine every day, equivalent to two eight-ounce cups of coffee, or three to four 12-ounce cans of caffeinated soda. Everyone has a different sensitivity to caffeine, so you should know your limits to avoid experiencing negative effects. There has been no scientific evidence linking moderate caffeine intake to major health risks, such as cancer, cardiovascular disease, or birth defects. However, you should cut back if caffeine makes you feel nervous, dizzy, or irritable, causes gastrointestinal aches and headaches, or hinders sleep.

Will I suffer withdrawal symptoms if I stop drinking coffee?

If you drink two or more cups of coffee each day, you will most likely experience withdrawal if you stop drinking coffee completely. The most common symptom of caffeine withdrawal is a headache, but you may also experience anxiety, fatigue, and depression. If you want to eliminate caffeine from your diet, it is best to reduce intake gradually. You could mix regular coffee with decaf, brew weaker tea, increase the milk in lattes, or drink juice instead of soda.

How much caffeine is in what I drink?  


Beverages Serving size (ounces) Amount of caffeine (mg)
Brewed Coffee 8 80-115
Espresso 2 80
Cappuccino 8 80
Iced tea 8 30
Chocolate milk 8 5
Hot cocoa 8 6
Cola drinks 12 38-46
Jolt 12 70