Just because you spent nine hours in bed doesn't mean you actually got nine hours of deep sleep. And when it comes to how energized you feel upon waking, integrative medicine physician Dana Cohen, M.D. says "the quality of sleep matters."
Most of our rest and recovery occurs in deeper sleep stages like REM sleep or slow-wave sleep, which we enter about 60-90 minutes after we doze off. If distractions like a snoring partner, an uncomfortable bed, or bright lights continually snap us out of these restorative stages, we may feel more tired in the mornings.
"Sleep quality can vary quite a bit, so it's not necessarily a problem if someone occasionally wakes up tired after a full night of sleep," says Janet Kennedy, Ph.D., clinical psychologist and founder of NYC Sleep Doctor.
However, if you continually wake up sleepy after what should have been a full night of rest—or feel like your morning fatigue is interfering with your life—it might be time to visit a sleep specialist to see if there's an underlying issue to address.