The reason that you may feel like hibernating at this time of year, going to bed early and getting up late, is not so much the cold as the day length. Humans evolved near the equator, where day length was fairly regular year round. Daylight (and the lack of it at night) was the cue for our ancestors’ daily life. They woke around dawn, hunted and gathered during the day, ate early in the evening, socialised and then settled down to sleep around 9pm. We know this because it is how hunter-gatherer communities live today. Although our modern lifestyles are very different from that, we still have an internal clock geared to the environment that we evolved in. That internal clock is known as the circadian rhythm, from the Latin circa ‘around’ and diem ‘day’, and disrupting it can cause all sorts of health issues: mental health problems, high blood pressure, heart disease, cancer, liver disease, obesity and diabetes to name but a few.
The good news is that you can support your circadian rhythm through the three pillars of health: sleep, food and exercise. Having a regular daily routine for these keeps your internal clock on time and so keeps you performing optimally.
To help you make it through the winter without wanting to go into hibernation:
- Wake at the same time every day
- Get bright light soon after waking and throughout the day, ideally daylight outdoors or being close to a window
- Have regular meal times
- Exercise during the day, but avoid high intensity sports after the evening meal
- Avoid caffeine after midday as it has a half-life of 6 hours and can adversely affect sleep
- Dim lighting in the home in the evening and use blue light filters on screens at that time of day
- Try to fast for at least 12 hours overnight, so no calories at all in that time, and have your last meal or snack of the day at least 2 hours before bedtime
- Go to bed at the same time every day allowing yourself at least 8 hours of sleep time every night.
It may sound like a big ask, and if you can’t tick all of these boxes every day, tick as many of them as you can. Making small, positive changes to your daily routine can have a big beneficial impact on your health in the long term, so it is worth spending some time thinking through what you can do differently to that end. And if you would like to learn more about the workings of your internal clock, I can recommend The Circadian Code by Satchin Panda. And this podcast on Tony Wrighton's Zestology Podcast with Nick Littlehales is worth a listen.