Morning Grogginess: Waking Up Tired With Sleep Inertia

Getting out of bed can sometimes feel like a battle. Our vision can be blurry, our brains confused, and we have no idea what day it is. Fighting the urge to slip back under the covers and close your eyes is easier said than done.

Even after a full 8 hours of sleep, it can be difficult to slip out of your snooze and prepare for the day ahead. This is what’s known as sleep inertia — a common condition where you can’t shake the haze of slumber. In this article, we’ll discuss the whats and whys and suggest ways to help prevent the wake-up struggle.

According to sciencedirect.com, Sleep inertia (also termed sleep drunkenness) refers to a period of impaired performance and reduced vigilance following awakening from the regular sleep episode or from a nap. This impairment may be severe, last minutes to hours, and be accompanied by polygraphically recorded microsleep episodes.

In layman’s terms, this simply means that feeling of grogginess when we wake. And it’s typically what causes us to fall into microsleeps as we begin our day.

You may think you shouldn’t wake up tired after 8 hours of sleep. This monophasic sleeping pattern should be enough to see you leaping out of bed in the morning, right? Well, not quite. Just like those old Windows PCs of the early 2000s, it takes your body a fair bit of time to ‘boot up’.

Our sleep cycle consists of four stages, and the transition from the final stage into a waking state causes sleep inertia.

During sleep, particularly the deeper phases, our bodies are immobilized with relaxed muscles and a low heart rate. If we are awoken in these stages of deep sleep, our bodies haven’t had time to set in motion what they need to wake up cleanly.

It’s best to wake in the REM stage of sleep. In this phase, your brain is at its most active. When we wake during REM, our body isn’t as deeply in slumber and we can more quickly adapt to the day ahead. As mentioned, it works the opposite way too, so it’s important to try and set your alarm to wake up when your sleep is at its lightest.

Top tip:

Use our sleep cycle calculator to identify when you are likely to be in your REM sleep phase. All we need is your usual or planned bedtime and our tool will do the rest.

To truly understand sleep inertia, we also need to be aware of how our bodies wake up.

The trigger to move out of our sleep state is stimulated by the Reticular Activating System (RAS). The RAS responds to external stimuli, such as the sound of the alarm clock or the rays of sunlight breaking through the curtains. The RAS then sends electrical signals to the parts of the brain that need activation to wake up. The issue is that once we do awaken, we still have a build-up of chemicals that we use to help us sleep.

Although scientists are still not exactly certain about what bodily processes cause us to wake up, there is an understanding of how we fall asleep.

The melatonin hormone and adenosine neurotransmitter are both key players for getting us to sleep and keeping us there. In relation to sleep inertia, studies suggest these linger on when we wake up.

It’s only once these chemicals have fully dispersed that we start to feel fully awake. It’s their presence post-sleep that causes the ‘sleep drunkenness’ we feel in the early mornings.

Feeling tired and groggy when waking up every day is entirely natural. In fact, 67% of people don’t wake up feeling refreshed each morning. Your body will always need time to charge up. However, if your mornings are difficult or impact the start of your day, speak to your GP about potential sleeping disorders. Identifying what may be causing your problems or changing your bedtime routine could do the trick.

In the meantime, discover the many ways you can get a better night’s sleep to prevent sleep inertia from dragging you down in the morning.