Why 8 hours of sleep isn't always enough

Sleep quality: Why getting your 8 hours isn’t always enough…

EVER WONDERED WHY…

… you often wake up after 8 hours of sleep still feeling tired and lethargic? It can feel almost as if you’ve not recovered or slept at all.

The problem may not be your sleep duration (how long you spend asleep), but instead your sleep quality.

Sleep quality refers to how much of your sleep is restorative.

This is dictated by how long you spend in the two most restorative stages: deep sleep and REM sleep.

DEEP SLEEP

This stage plays a critical role in knowledge consolidation and physical restoration.

Not getting enough of it could be why you don’t remember those facts you learned yesterday and why you aren’t as physically recovered.

Hallmarks of deep sleep are lower core body temperature, little movement (no tossing/turning), and a lower and stable heart rate.

REM SLEEP

Do you sometimes feel irritable, short-tempered, and erratic in the morning? It could be because you didn’t get enough REM last night.

Which makes sense given it’s responsible for things like memory consolidation, emotional regulation, and creativity/problem-solving.

(P.S. it is during REM that dreaming predominantly occurs.)

HOW TO GET MORE OF EACH

When it comes to getting good quality sleep, which largely translates as getting more deep and REM, the focus in the run up to bedtime should be on these 3 principles:

Reducing physiological activation

How? Set your routine up so it includes activities which bring your heart rate and core body temperature down. Avoid activities which do the opposite.

Why? A lower core body temp and stable/lower HR is an essential requirement for getting sufficient deep sleep.

Do:

• Meditation, breath work, reading, aromatherapy etc (to bring down heart rate promoting relaxation)

• Keep the bedroom cool (16-19°C / 60-67°F), take a hot shower 30-60 minutes before bed (paradoxically, this cools your core as the heat rushes to your skin)

Don’t:

• Eat or exercise within 3-4 hours of bed time (this elevates HR and core body temp)

• Avoid alcohol (this triggers a stress response, causing HR to elevate)

Reducing mental stimulation

Here the focus is on avoiding things which are going to trigger or excite you.

Why? Increased mental stimulation can trigger stress responses disrupting REM sleep.

Do:

• Avoid stimulants such as addicting content 60 mins before bed (e.g social media/video games), caffeine (8-10 hours before bed) and substance use

• Try to avoid strong overhead lighting (bright lights at night simulate daytime)

• If stressed, try to decompress before bed. Journalling (writing down your concerns), meditation, and breath work can be effective to achieve this.

Minimising potential disruptions

The aim is to reduce the chances of sleep being disturbed and waking up prematurely.

Why? Waking throughout the night for extended periods disrupts the natural flow of sleep, reducing both REM and deep sleep.

Do:

• Ensure your room is as quiet and dark as possible (consider ear plugs and/or a sleep mask - I’ve linked the ones I use)

• Avoid liquids 2/3 hours before bed to reduce the need to wake for the bathroom

DISCLAIMER

The general principles in this post are aimed at increasing awareness of what you can do to improve sleep.

We are all unique, and the same blanket routine may not work for everyone.

It’s about testing, tracking (with a health tracker e.g Apple Watch, Whoop, Oura) and seeing what changes are most beneficial for you.

Then it is about building a sleep routine that works sustainably over time. Don’t try to be perfect, where’s the fun in that?

Note: When avoiding liquids and eating earlier, ensure you stay hydrated and get sufficient calories. Just try to achieve this ~3 hours before bed.

PLEASE NOTE

I research each topic thoroughly before sending each newsletter. However the science is ever-evolving. The information, at the time of sending, was accurate to the best of my knowledge.

The information contained in this newsletter is not medical advice, and I am not medically qualified. You should always research independently or consult a medical professional before making any changes to your lifestyle, including on the subject discussed here.

Not all sleep concerns can be fixed with a good routine. If you suspect you may suffer from a sleep disorder (sleep apnea, insomnia, etc.) consult your doctor.

Sources:

(Walker, 2008), (Fattinger et al., 2017), (Nishida et al., 2008), (Groch et al., 2013), (Debellemanière et al., 2018), (Pal et al., 2023), (Ajwad et al., 2018), (Black et al., 2015)