Why Winter Makes You Tired: Your Body Clock, Sleep & Mood Explained

Right, so now it's time for this week's check-in, which is all about the winter months.

And we're looking specifically at our body clock.

How does winter affect our body clock and our just sense of wellness?

So it affects you.

your circadian rhythm, which is your internal body clock, because our biggest kind of signal that our body clock goes on is daylight.

And there is a lot less daylight during these winter months.

So basically, when you are out in daylight...

Your eyes are not just seeing the daylight, that daylight is going to the back of the eyes and there are special receptors or cells in the back of the eyes that make something called melanopsin, which is a signal or chemical signal that goes off to a part of your brain called the suprachiasmatic nucleus.

And that is where the clock lives.

That tick-tocking clock in your brain that tells you it's morning, tells you it's night time, tells you it's time to eat, tells you it's time to go to the toilet.

All of those things are all built into this body clock.

It doesn't just affect that.

It affects all sorts of things in your body.

So people think... oh, my internal body clock will just tell me when it's time to wake up and when it's time to go to bed.

It does so much more than that.

One of the fascinating things your internal body clock does, and this is quite relevant to winter, is that it can help regulate your immune system as well.

So what we've seen in studies is that Your immune system, we know our immune system is really good in that, you know, it switches on when it needs to switch on and it fights off infections.

And then it's got brakes in place to stop it from overdoing things, right? What we found in these studies is that in daytime hours, in particularly early morning, early afternoon, when your body clock is in sync with the rest of your body and your routine...

it helps govern how well your immune system is working particularly in those daytime hours and then it slows it down is that why we

get more ill in winter

it could be because it could be i mean it's biologically plausible isn't it because if it's slowed down in the darker hours it's there's less time for it to be active right part of it is also the way viruses work you know we we We are outdoors less, we're inside more, and viruses spread more indoors and all of this kind of stuff.

And people don't aerate rooms or burp their houses, as I know you like to say.

But yeah, your immune system could play a big part of that.

Really interesting, and this going off topic, but really interestingly, there are studies that show that drugs that are used as immunotherapy drugs to treat cancers, in particular melanomas, lung cancer, kidney cancer, are... are thought to be more effective when given earlier in the day than later in the day.

And survival rates for people with the same cancer, depending on where their immunotherapy is given, they have better survival rates when they're given in the early morning rather than in the afternoon.