There’s something extra special about the feeling of going to bed without needing to set an alarm.

With no set time to anxiously count down to as you toss and turn, it’s a chance to fully relax and unwind without the pressure of the morning looming over everything. And that’s not forgetting the opportunity it offers to try to ‘catch up’ on the sleep many of us regularly miss.

As someone who tends to be quite busy throughout the week, the draw of a weekend morning without an alarm often gets me through the most fatigue-inducing parts of my schedule. It feels like I’m giving my body the chance to even the playing field and eat up all the sleep it needs before the week ahead.

But is that really true? Is allowing your body to wake up naturally without an alarm really an effective way to ensure your body is getting all the sleep it needs, or is it more complex than that? 

I’ve always assumed that sleeping in without an alarm allows my body to choose when it wakes up, therefore giving it the opportunity to get all the sleep it needs. However, it turns out that’s not exactly the case.

“While sleeping in without an alarm may help you get an extra hour or so of sleep, it doesn’t guarantee that your body gets the sleep it needs,” says Sammy Margo, Dreams’ sleep expert. This is because there are plenty of factors that influence why, how and when we wake up – with the amount of sleep we need being just one.

“We wake up without an alarm due to a complex sequence of chemicals,” Margo explains. “When we’ve had enough sleep and our circadian rhythm is functioning properly, we are more likely to wake up in a natural way without an alarm clock.”

However, she adds: “Factors such as stress, diet, exercise and even our bedroom environment can also influence when we wake up. High levels of stress can cause us to wake up earlier and a healthy diet can help improve the quality of our sleep meaning we feel good when we wake up.”  

On top of these factors, the way our sleep is structured – in periods called ‘sleep cycles’ – can also cause us to wake up at a variety of different times.

Dr Lindsay Browning, a neurologist, psychologist and sleep expert at And So To Bed, explains: “Each sleep cycle tends to last around 90-110 minutes, and between each sleep cycle everyone tends to wake briefly at a point where the sleep is lighter.

“If you don’t use an alarm clock you will likely wake naturally at one of these points of sleep, and if you have had enough sleep at that point you will not have enough sleep pressure to go to back to sleep again (or in other words you won’t be as hungry for sleep because you have already slept.”

So, while having enough sleep can cause us to wake at the end of a sleep cycle, it’s not the only thing that can wake us up when we sleep without an alarm.  

We’ve all come across the idea that spending too much time in bed can make you more tired, but is that true? Is it possible to ‘oversleep’ – and can doing so lead to feelings of fatigue? Again, it’s complicated.

While it is possible to oversleep, the feelings of fatigue many of us are talking about when we describe this situation probably aren’t to do with excess sleep.

“If you wake up later than your usual wake time, you may wake from a deeper part of sleep,” Dr Browning explains. “This means you may wake up with sleep inertia, meaning that you may feel groggy upon waking because you have woken from this deeper part of sleep.

“Some people interpret this sleep inertia as a sign that they have overslept, however it’s just the result of waking from a deeper part of sleep and has no relation to how restorative your sleep was.”

Oversleeping every so often isn’t necessarily bad for you. However, sleeping too much on the regular can lead to long term health issues in the same way that not sleeping enough can too. 

Everybody’s sleep needs will be different, and sleeping in without an alarm isn’t the most accurate way to tell how much sleep you need. Instead, you’ll need to rely on a combination of timings and how you feel.

“It takes a long time to understand how much sleep your body needs, and it can completely vary on several factors including age and lifestyle,” Margo explains.

“It’s important not to rely completely on the results from a sleep app or smart watches and focus on how you feel when you wake up in the morning and if you feel good and energised throughout the day.” 

Browning agrees: “For most adults, somewhere between 7-9 hours sleep is likely the right amount of sleep, according to research.

“If you fall asleep within around 20 minutes, are not awake during the night for more than around 20-30 minutes, don’t wake more than around 20 minutes before your alarm, feel refreshed during the day, and have had somewhere between 7-9 hours sleep, that is likely the right amount.”  

Images: Getty