Not All People Respond To Caffeine The Same

BOSTON (CBS) - Is your partner able to drink several cups of coffee before bed yet one cup keeps you up all night? As it turns out, some people may be more sensitive to caffeine than others, probably due to genetics.

Researchers found that there are three main ways that people respond to coffee depending on whether their liver breaks down caffeine quickly or slowly and whether their brains are more sensitive to the stimulating effects.

In people with high-sensitivity, even small amounts of caffeine can be arousing and cause sleep problems. Those with "regular" sensitivity to caffeine can drink 2-5 cups of coffee a day and feel more alert but won't feel any unwanted effects. And in people with low sensitivity who metabolize caffeine quickly, large amounts don't do much of anything. These people need to be careful not to drink more than five cups of coffee a day trying to get the desired effects.