Circadian Rhythms

Or: I wanted to skip my afternoon nap, but I didn’t have time

I’ve been aware of circadian rhythms for many years but they have recently come back into my focus after listening to several episodes of the Feel Better, Live More podcast and the work of Nick Littlehales. The ideas (and how they could improve my life) resonated so strongly with me that I quickly became fascinated.

To start, let’s get our definitions straight. Circadian Rhythms are natural cycles within the human body that determine, among other things, sleepiness and alertness. The rhythms themselves are affected by light and dark and the sleep patterns of the person in question. One cycle lasts about 90 minutes, with the first half being a period of more alertness, and the second half being a period of less alertness and more sleepiness. You are most likely to wake up naturally during the “alert” section, and you can consider this the start of your first cycle for the day.

(I’ll also add that this is not new-age airy-fairy medicine. There’s lots of studies on circadian rhythms and in 2017 someone won the Nobel Prize for research in this area!)

The most obvious issue is if you try to go to sleep at a period of high alertness: you are very unlikely to fall asleep. This can lead to frustration which leads to even less ability to sleep. Fortunately, the solution is simple: time your bedtime with a dip in alertness. This might be bleeding obvious because I’m basically saying “go to sleep when you’re tired” – but a lot of people don’t do that! They go to bed at some arbitrarily defined bedtime (or when the TV show you’re watching finishes) that might not be the right time. If you’re not sleepy wait around 45 minutes and a dip might just come along.

Beyond this, we can use our new knowledge to help plan ahead. Let’s say you are yawning at 9pm: probably a little early for most people to want to go to bed. However, this is an indicator that you are in a dip, and that the next one will arrive in around 90 minutes, so 10:30pm would be a good time to plan to go to bed.

This method can be enhanced and refined through routine – by getting up and going to bed at similar times you can know in advance at what points you will be most alert and most sleepy through the day and plan accordingly.

The beauty of knowing about circadian rhythms, however, is you can take advantage of it even if your routine is disrupted, or you don’t have a regular routine because of (for example) shift work. You don’t have to throw yourself into bed at the soonest moment and deal with the ensuing frustration of insomnia – you can be more efficient by timing it with the cycle.

I often struggle with waking up in the middle of the night and being unable to get back to sleep. I get annoyed and anxious that I’m wasting time that I’m neither working in, resting in nor enjoying. Circadian rhythms brought the revelation that it was actually natural and totally ok to wake up during the night; it’s simply a point of alertness in the cycle. Historically it has been typical for people to get up and do something for a period during the night, and then go back to bed and return to sleep. By doing this we are not disrupting our natural cycles but working with them to be more content and relaxed. I know now that when this happens I don’t have to freak out, I can just roll with it.

One of the nice things about knowledge of C.R. is that it takes the stress out of a lot of things. It is nice to know it’s natural and normal, when waking through the night or during the day when there are periods of tiredness.

Speaking of daytime tiredness, C.R. help us with this too. Everyone is aware of the “post-lunch slump” at work, when it feels like you are moving through treacle. This is a natural consequence of C.R. and it’s comforting to know if you weather the storm for 45 minutes a wave of alertness will arrive. We can take this further, however, and make the most of our dip in alertness. Rather than pushing through with very low productivity, why not have a nap? It will come naturally due to the point in the cycle, and it will enhance productivity during the upcoming alert phase. It is even possible that just taking a rest and a break during this downtime (without actually sleeping) can help.

Now obviously there are many more factors to good sleep and good health than managing circadian rhythms, but this area is not well-known and offers simple, significant benefits. Honestly there is much more to be said on this and here I have just distilled my biggest personal takeaways. If any of this resonates with you I would strongly recommend listening to this episode of the Feel Better, Live More podcast ( or reading Nick Littlehales book (

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