If you are reading this, you will probably have read ‘Part 1’ from my sleep series blog and you will know I have not always been committed to getting decent quality and quality of sleep. In fact, you will know that until fairly recently, I was a ‘I only need 4 hours a night’ kind of a gal. Improving my sleep has without a doubt been one of the most impactful changes I have made in my life – benefiting me physically and mentally in more ways than I can do justice to describing here.
You can't get away from it. Sleep impacts everything. Sleep impacts our entire being. Sleep is a fundamental part to elevating our human performance as it is critical for all levels of your functioning: brain, body, and mind.
The science of sleep:
Sleep is not the opposite of being awake. Sleep is part of the 24-hour circadian cycle or /body-clock’. Sleep is a complex physiological event in an ordered series of stages. Each stage benefits the brain and the body in slightly different ways.
The 24-hour circadian cycle defines when it is that we sleep, determines when we are awake and the timing of our various bodily functions.
If there is any one point, I hope you will take out of this blog is that everything you do while you are awake, determines how you sleep. And this is because our awake state and sleep state are closely linked through this 24-hour circadian cycle. They are part of a phased and staged physiological event.
Daylight and sleep:
Light matters. Sunlight and daylight matter. If you follow neuroscientist, Andrew Huberman (https://hubermanlab.com), you'll see that he talks about getting daylight/sunlight in through your eyes early in the day as one of the most important factors to your health and wellbeing and positively impacting your sleep.
This is because the brain uses sunlight to set our 24-hour clock. When we wake up and open our eyes, if we then get sunlight in through our pupils, it hits the back of our eyes. Our retinas are connected to our brain, so this triggers off a cascade hormones and neuromodulators that starts the 24-hour circadian cycle.
The daylight entering our eyes, sets the time that we will then begin to want to fall asleep or feel sleepy towards the end of the day. Daylight hitting our eyes sets our period of wakefulness for 12 to 16 hours thereafter – it varies between people. In other words, our wakefulness sets our sleepiness. What you do early in the day will impact how you sleep, the quality of your sleep and when you sleep.
Melatonin and sleep:
Most people are aware melatonin is linked to sleep.
A question I am asked often is:
“Should I use melatonin to help me sleep?”
Melatonin is released by the pineal gland, in the brain and is in fact derived from serotonin. As it becomes dark, the pineal gland releases melatonin, and the melatonin levels build up and peak around the time of sleep.
In essence, melatonin's role is to tell the brain and body that as it is dark, you can start to prepare for sleep. Melatonin does not do much for generating sleep. It just tells us when it's time to sleep. Therefore, using melatonin supplements will not necessarily help your quality of sleep. And in fact, many of the sleep experts suggest avoiding its use.
While we are asleep, melatonin levels begin to drop. When we wake in the morning, the sun hits our eyes, and it turns the pineal gland off. Melatonin then shuts down until we start moving into the period of dusk later in the day.
Adenosine and sleep: What is adenosine?
Adenosine is important in the regulation of our sleep cycle. From the moment we wake, adenosine builds up in our system, and once the levels reach a critical point, it creates a craving for sleep. A ‘sleep hunger’. The longer you are awake, the higher your adenosine. Adenosine peaks 12 to 16 hours after you wake, driving your need for sleep.
One of the reasons I have included adenosine in this blog is because of its link with caffeine.
Adenosine and caffeine explained:
The consumption of caffeine blocks adenosine uptake. When you drink caffeine, adenosine is not taken up by the cells, but remains circulating in your body. The caffeine blocks the adenosine until it wears off. Once the caffeine wears off, all the adenosine that has been building up, floods into our systems. We are then hit with a ‘crash’: tiredness, and a desire to sleep immediately!
Something I learned from neuroscientist, Andrew Huberman’s podcast, is that if you drink your coffee really early in the day, and you notice you have a crash around midday or early afternoon you may want to have your first coffee a little later. A simple tip is to experiment with the timing of your coffee so that any slump you may experience will occur much later in the day rather than during a time you may want to be productive/focused.
Two types of sleep - REM and non-REM sleep:
Is REM sleep more important than non-REM sleep?
These two types/phases of sleep are paired together and cycled. We go between REM and non-REM sleep, every 90 minutes. Both phases are equally important as they both have very specific functions for our brains/bodies.
Non-REM sleep tends to occur more in the earlier part of the night and REM sleep much later in the night. So whenever people ask,
‘Is it better for me to get up earlier or is it better for me go to bed later if I need to cut sleep?’, I explain that neither option is better than the other!
You’ll either miss more REM sleep on one hand or non-REM on the other. And both of those are equally important.
What is insomnia?
Insomnia is suffering from the inability to be able to generate a good quality and quantity of sleep. It is not being able to get good sleep, but not allowing yourself to do it. It is not denying yourself the opportunity to sleep.
Most people with sleep challenges, struggle with the onset of sleep or struggle to maintain their sleep, and unfortunately some people, struggle with a mix of both.
What to do to improve your sleep:
Insomnia and difficulty sleeping are linked to anxiety and worry. It can help some people to check off some of the mental tasks or things that they are worrying about during their wind down before bed. Journaling, writing a task list etc. can prepare your mind and allow you to feel you have addressed some of the things weighing on your mind before bed.
I have already mentioned getting light in your eyes early in the day (more details below), however I also suggest you think about your exposure to light towards the end of your day. Bright lights and artificial lights in your environment close to bedtime makes your brain think that you're still in the middle of the busy working day. In order to start releasing melatonin (see section above) you want your brain to be cued that it is in fact dusk and bedtime is approaching. As you already know, minimizing your phones, laptops, and bright TV screens closer to bedtime is beneficial. I also suggest dimming the lights in your home in the evening to create a lower light environment.
Another useful tip is around body temperature. To have ideal sleep, you need your core body temperature to drop a few degrees. Having a warm shower or a warm bath before bed, creates vasodilation of your blood vessels and this cools your core body temperature. Being able to pop out a hand or a foot out from under the duvet while you're sleeping is helpful as this is a way you can drop your body's core temperature and help you sleep better.
Alcohol – in a nutshell alcohol does not benefit your sleep. In fact, it is the opposite. Alcohol is not a sedative, and it lowers your sleep quality.
Try to get up at the same time every single day. Do not make the mistake of sleeping late on a weekend to try to catch up on your sleep. This will just make it more difficult for you to get into a circadian cycle.
I am a big fan of the afternoon nap. I like to call it a snap (combination of a snooze and a nap) but try to only nap before 3:00 PM and try to limit it to 30-45 minutes.
Try not to go to bed if you feel full or have just eaten. The opposite is also true - it can also be hard to sleep when you are hungry.
Timing your exercise – for some people, exercising late in the day/evening/night can make it difficult to sleep. If you are struggling with your sleep, consider moving your (especially your cardiovascular) exercise, to earlier in the day.
Prof Matt Walker,( https://www.sleepdiplomat.com/professor) one of the world’s leading experts warns of the impact of coffee consumption. Caffeine has a half-life of 5-7 hours – this means that only 50% of your 4pm coffee would have worn off by 9-11pm. I would therefore, at the very least, limit your intake and not consume caffeine after midday.
Get that morning sunlight in early. When you wake up, get up and go outside. Get anywhere between five to 10 minutes (or more if it's very cloudy and overcast) of sunlight – do not wear sunglasses and of course, please do not stare into the bright sun!
I also suggest exercising early in the day if you can - some of the hormones that get our circadian cycles going, can be released by exercise. Setting the circadian cycle early will tee us up for being ready for a good night of sleep later on.
Yoga Nidra and NSDR (Non Sleep Deep rest) can benefit your sleep – performing an NSDR meditation or Yoga Nidra during the day can benefit your sleep later on and can also be useful to use just before bed or if you are struggling to sleep at night.
In summary: As Prof Walker says, “Sleep is a repeat prescription that is available for you to use every single 24 hours. A prescription to benefit your brain and body and positively impact your wellbeing and your outcomes in your life.”