Black coffee without dairy or sweeteners has several health benefits, but drinking it at night could have consequences. Because it contains a large dose of caffeine, coffee can get in the way of obtaining a good night's sleep. A study on caffeine's effect on sleep proves that drinks like coffee consumed at night can cause sleep disturbances. The study also recommended that caffeinated beverages should be consumed more than six hours before attempting to fall asleep. Try swapping your coffee for an herbal tea for bedtime.