Dear Doctors: I recently heard about something called sleep inertia. This came up in a conversation about how to sleep better at night. Is this true? I often don’t feel refreshed when I wake up and wonder if sleep inertia is to blame.
Dear reader: Sleep inertia sounds like one of those health memes trending on social media, but it’s true.
This refers to the persistent lightheadedness that sometimes occurs when you wake up. This is a temporary condition that usually subsides in about 30 minutes. However, in some cases, symptoms may take several hours to disappear.
People with sleep inertia wake up feeling heavy, groggy, and out of sync.
Symptoms vary in intensity and duration. This condition is known to be more pronounced among night shift workers, teenagers, and people who already have significant sleep debt.
The reasons behind this transient state are not fully understood.
Brain scans of people experiencing this condition show that some sleep-related functions persist despite being awake. An important factor in the likelihood of its occurrence and its strength is the person’s sleep stage at the time of waking up.
Sleep inertia is much more likely to occur when someone is suddenly pulled out of slow-wave sleep (the deep, restorative stage of the sleep cycle). If your alarm clock goes off when you’re in a light sleep, the transition to wakefulness is usually smoother.
Fluctuations in core body temperature are part of the nightly sleep cycle. Sleep inertia tends to be stronger when wakefulness coincides with the lowest point of temperature change. Other factors include being out of sync with your circadian cycle, having an underlying medical condition, and using certain medications.
Sleep inertia can interfere with thinking and decision-making, negatively impact learning and short-term memory, and lead to decreased reaction times.
Research has found that certain strategies can help:
- If you nap, limit it to 10 to 15 minutes. If you take long naps, you run the risk of waking up later in your sleep cycle.
- Bright light suppresses the sleep hormone melatonin. Exposure to bright light when you wake up can help you recover faster from long periods of inert sleep. The same effect is not seen in short episodes.
- Caffeine has been shown to shorten recovery time.
- It is important to have a consistent bedtime and wake-up time.
- There’s also evidence that repeatedly using the snooze button to extend your sleep can lead to sleep inertia.
If you continue to feel light-headed in the morning and it is interfering with your quality of life, consult your doctor.
Dr. Eve Glazier and Dr. Elizabeth Ko are internal medicine physicians at UCLA Health.
