Have you ever wondered how your body keeps track of time, how it knows when you should sleep and when you should be awake? Why are some people hungry when they wake up, while others only get hungry a few hours later? And why do the winter months, with their lack of sunlight, have such an effect on mood and energy levels?
The answer is not just outside, with the grey skies and 6-hour long days, it is really inside of us.
Our bodies are governed by internal biological clocks, present in nearly every cell. These cellular clocks are the ones that regulate our daily systems: rhythms, sleep, appetite, energy and mood. This predictable and recurring slump (hello, November) is not just a result of decreasing daylight, it is also attributed to the biological failure caused by your internal clocks becoming out of sync with the outside world. Our internal clocks and external environment become misaligned, causing our biological functioning to become less effective. When this happens, our biology works against the schedule we are supposed to be keeping.
Your body functions as a 24-hour system, regulated by thousands of tiny biological timers or ‘clocks’ within all of our cells. These are called the peripheral clocks. They are all specialised; some control the metabolism of the liver, others, regulate sleep in the brain. They all have their own very specific purpose.
Overseeing this cellular network is the ‘master clock’. Living deep within your hypothalamus (the part of the brain that links your nervous system and endocrine (ie hormonal) system). This part is in charge of your critical functions: mood, energy and appetite and it runs on a circadian rhythm (a fancy word for your internal body schedule). It relies heavily on light to stay on track.
So what happens during winter?
As winter arrives, and daylight hours diminish, your master clock – which previously relied on the duration of its darkness to set its schedule – gets confused. To put it simply, when it gets darker, your brain begins producing melatonin way too early.
The shrinking days begin to create a misalignment in your body. Your internal system does an entire shift, a phenomenon known as the ‘phase delay’. Your body falls into a mismatch, your delayed biological rhythms fighting with the fixed schedule of the external world. The 9-5 becomes the crux of the problem. Your body wants to sleep and wake up later, but your timetable doesn’t allow it, so your brain and schedule start playing tug-of-war.
This misalignment sends your body into a frenzy – and you experience fatigue and hypersomnia as well as carbohydrate cravings, ultimately setting you up for failure. These symptoms are shared with seasonal behaviour observed in mammals such as bears, and we believe they are an echo into our ancient human evolution, intended to conserve maximum energy in the winter months. This is extremely inconvenient, but reassuring to know that it is biologically harder to wake up for that 8am class, and our bodies might just not be designed to be doing such demanding things before 10am.
Alongside this, studies have found that even if you do not fit into the category for full Seasonal Affective Disorder (SAD), a significant portion of the population still experiences something called ‘Winter Fatigue’. This is almost a sub-category of SAD, but still a very common and normal thing.
Winter darkness doesn’t just affect the brain; when your internal clocks become out of sync, and communication between the systems becomes less efficient, your heart, metabolism and nervous systems become misaligned.
What now?
Okay now you might be thinking: thank you for this depressing news, but what do I do now? I can’t go hide in a cave and hope this degree will fix itself. Well, there are some tried and tested methods that help with these problems.
There are some small things you can do that will make a big difference: exposure to morning light (even grey November light) is enough to wake up your brain. Studies say that it’s best to see morning light 8.5 hours after falling asleep, as it tells your body that it’s daytime. Step outside during daylight hours. More studies have even shown that being outside for 10 minutes increases social engagement, and overall well-being. If you want to happiness-max your day, exercise plus daylight hours is the ultimate combination to feel happiness again. And of course, take your vitamin D.
Winter is your time to slow down, even when your schedule doesn’t. So when you begin to feel more tired, not so motivated or just out of sync, don’t fight it too hard. Be kind to yourself. Rest more. And until the light comes back, just ride the wave.
