Read labels and make that next after-dinner cappuccino a decaf. Nicotine is also a stimulant. It makes falling asleep more difficult. The withdrawal that occurs overnight impairs sleep and makes it more difficult to awaken in the morning. Alcohol may relax you and make you sleepy but that also has a catch.
Alcohol relaxes the muscles and makes snoring and sleep apnea worse.
Sleep apnea occurs when the tongue and soft tissues in your throat block off the airway. The body reacts to this by waking you up just long enough to breathe but not long enough for you to remember awakening. These arousals disturb your sleep and leave you exhausted in the morning. For example, drugs used for asthma, over-the counter diet pills, and decongestants are stimulants and make sleep more difficult. Antidepressants can be activating, causing you to feel more awake or sedating, causing you to feel sleepy.