ou sleep for seven to eight hours almost every night, only to feel unrested through the morning or even most of the day. How could you be following a golden rule of sleep so right, yet feel so wrong?
This discrepancy is often due to a heightened state of sleep inertia, a circadian process that modulates memory, mood, reaction time and alertness upon waking, according to a 2015 study. Some people experience impaired performance and grogginess in this period after first turning off the alarm. The effects of sleep inertia usually go away after 15 to 60 minutes but can last for up to a few hours.
Sleep inertia impairs more sophisticated cognitive skills such as evaluative thinking, decision-making, creativity and rule usage, and gets worse the more sleep deprived a person is.
But even if your job isn't saving lives or driving a truck overnight, experiencing sleep inertia for hours can still affect your quality of life.
The way to address this begins with evaluating your sleep using the "two Qs," said pulmonary and sleep specialist Dr. Raj Dasgupta, a clinical associate professor of medicine at the University of Southern California's Keck School of Medicine. "If you're getting the good quantity sleep, the next question is, 'Am I getting good quality sleep?'"
Dasgupta suggested seeing a sleep specialist, who can check for an underlying or primary sleep disorder. But there are other more easily modifiable factors that could be interfering with the restoration and recovery processes -- such as memory consolidation, hormone regulation and emotional regulation or processing -- that need to happen during sleep.
"There are a lot of conditions that cause fatigue, but they don't necessarily make people feel like they're ready to fall asleep," said Jennifer Martin, a professor of medicine at the David Geffen School of Medicine at the University of California, Los Angeles, and president of the American Academy of Sleep Medicine.
These can include chronic pain conditions, metabolic or thyroid conditions, anemia, and chronic obstructive pulmonary disease.
If you're feeling inexplicable fatigue, "an important first step might just be a routine physical with your family doctor," Martin said.
Additionally, the National Sleep Foundation has said healthy adults need seven to nine hours of sleep nightly, so you might need more than eight hours of sleep to feel energized. You could try going to sleep an hour earlier or waking an hour later than usual and see if that makes a difference, said Christopher Barnes, a professor of management at the University of Washington who studies the relationship between sleep and work.