Sleep Calm & Carry On: Is a Lack of Sleep Making Me Tired and Angry?

Posted by Dr Sophie Bostock - Sleep Expert on 9th Jul 2024

Sleep Calm & Carry On: Is a Lack of Sleep Making Me Tired and Angry?

Dr Sophie Bostock, our very own sleep expert, has been looking into why so many of us feel tired during the day.

The first question to ask if you’re feeling tired on a regular basis, is whether or not you’re getting enough sleep.

Let’s face it, no-one wants to be sleep deprived, but modern life can be relentlessly busy. Whether it’s work deadlines, childcare or caring for a loved one, ,a mind that won’t switch off, or simply striving to carve out a little ‘me time’, there are many reasons that sleep time can get squeezed. So how do you know whether you’re getting enough?

How much sleep do I need?

Research suggests that the majority of adults need between 7 and 9 hours sleep every night to be able to function at their best.

This recommendation is for ‘the average adult, and you may be different. And as we get older, we need slightly less sleep than we used to. Athletes (who train on a regular basis) may need a little longer in bed each night. A small minority of people carry a ‘short sleep’ gene; they can consistently wake up after 5 hours and feel refreshed, but this is rare.

Why do I need sleep?

A woman suffering from a lack of sleep lying asleep face down on the couch

So, you may be thinking why do I need a minimum 7 hours per night?

First off, sleep is not just about replenishing your energy. Sleep performs crucial housekeeping tasks for both your body and your brain. It helps to store memories, get rid of toxins, process emotions, and repair damaged cells.

The longer term risks associated with sleeping for 6 hours or include higher rates of depression, anxiety, diabetes, heart disease, infection and cognitive decline.

This may sound worrying if you’re struggling to get enough sleep, but it’s important to remember that chronic diseases are influenced by many factors – not just sleep. If you focus on making positive lifestyle choices during the day – such as exercising regularly, eating healthily, and managing your stress levels – you may be able to compensate for some of the health impacts of less sleep.

But here’s the thing – short sleep makes making healthier choices so much harder.

The importance of a good night’s sleep

Our brains evolved during the hunter gatherer era. To our ancestors, a lack of sleep probably meant they were in danger.

As a result, when you don’t get enough sleep, your brain dials up your sensitivity to threat and your fight or flight stress response goes into high alert. This means that when you’re tired, you’re more likely to feel tense, irritable, and anxious.

At the same time, our brains de-prioritise activity in the logical prefrontal cortex. This can result in us becoming more impulsive. It may also lead to difficulties with being able to concentrate and reduce our ability to adapt to new information.

What do we know about the effects of a lack of sleep?

A man sat at his computer rubbing the bridge of his nose as he tries to concentrate while suffering from a lack of sleep.

Couples who are sleep deprived are more likely to argue. Bosses that are short of sleep are more likely to be accused of bullying behaviour. Workers not getting enough sleep are more likely to procrastinate.

The occasional night of short sleep here or there , and we’ll quickly bounce back, but sleep debt builds. So, if you’re routinely ‘getting by’ on fewer than 6 hours sleep per night during the working week, by Friday your mood and concentration will really start to suffer.

So how do you know how much sleep you personally need?

As a rule of thumb, you need enough sleep so that you don’t feel sleepy during the day. By not feeling sleepy, I mean without relying on caffeine or sugar to pep you up during the day and not relying on extra sleep at the weekends to catch up.

If you usually fall asleep within 5 minutes of your head hitting the pillow, it’s may be a sign that you’re not getting enough good quality sleep.

If you have at least 4 days off, try this exercise:

Go to bed in the evening when you naturally start to feel sleepy. Allow yourself to wake up without setting an alarm clock. You can doze if you feel like you need to. You might sleep in for a few mornings, but it’s likely that after a few nights of catch up sleep, your sleep and wake times will start to fall into a more regular pattern that reflects your true sleep need.

What else can I try to get my sleep back on track?

Another method of working out how much sleep you really need is to start keeping a sleep diary. For a week, write down the times that you go to sleep and wake up, and keep a note of how you feel during the day. We’ve created a sleep diary template for you to print out to make this easier to do.

When you understand your typical sleep pattern, you can start to experiment. For example, how do you feel if you go to bed 15 minutes earlier, or wake up 15 minutes later, for a week? 

For a quick recap, watch the video below:

In the next step of our Sleep Calm and Carry On Programme, we’ll look at how to use a sleep diary to improve the quality of your sleep. This can help make it more likely that you’ll wake up feeling refreshed.

Thanks for reading. Sleep well!

authors profile
Dr Sophie Bostock
Sleep Expert
Sophie brings a wealth of expertise to the role having spent the last six years researching and championing the importance of sleep science in NHS and corporate settings. Sophie was responsible for improving access to the award-winning digital sleep improvement programme, Sleepio, as an NHS Innovation Accelerator Fellow. She has delivered hundreds of talks, including for TEDx and Talks@Google, and regularly features as a media sleep expert.
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