🧬 A little biology lesson

Why we feel sicker in the evening

This one is going to be a fusion of psychology and biology. It’s slightly different than what I’m used to, but having caught an ear infection over the past week and experienced all the symptoms that came with it, I am unfortunately left with one burning question.

When you’re ill, why do you always feel worse in the evening?

I caught the infection on Saturday, and the bank holiday weekend gave me just about enough time to stop being in excruciating pain. The following week overall felt strange. You’d start the day off feeling awful, then it would get kind of better, and I could have sworn the pain was much more intense in the evening.

Is it your mind playing tricks on you, or are you actually more ill in the evening?

Before we get to the answer to the main question, let me take you on a slight detour (I promise, it will come back around!). When I was thinking about why my infection felt worse in the evening, I was reminded of a story I heard on a Radiolab episode a while ago. (Trigger warning: this story involves some references to child pornography.)

It was about a man who suffered from epilepsy. His seizures had gotten so bad that he decided to have a brain surgery because it was no longer sustainable. Removing parts of your brain, as I’m sure you’ll guess, is consequential, to say the least. There’s so much risk attached to it, and you could easily remove an essential part by mistake and lose the ability to speak. But he had done this before, so he was confident that nothing was going to go wrong.

He had his second surgery. Everything seemed to be fine, until one day he felt a change in his appetite. He had always been a sensible eater, but all of a sudden his sense of appetite went through the roof. And so did his sex drive. And the most peculiar one of all, he started consuming some untoward content (to put it very mildly), namely child pornography.

This was obviously unacceptable behavior. But long story short, there was a real biological explanation for it: he’d had part of his brain removed — the part which was responsible for giving him neurological control.

But there was another layer to the story. Despite the argument that he had no sense of control, this guy was able to hold down a job, and there was no trace of child porn on his work computer. Everything was found only on his personal computer. The argument was, if he truly had no sense of control, then surely he should have left evidence on both computers. In a moment, I promise I’ll tie this back in with my (now in comparison very very) mild story of an ear infection.

The effect of sugar levels on the brain

In the end, the guy was sent to prison for 26 months, and was on house arrest for the remaining 25 months. Robert Sapolsky, an expert in the world of neurology, however, had a very interesting take on this story. He argued that the computer evidence was not an indicator of whether or not he had a true sense of control. Your frontal cortex, which is responsible for making complicated decisions and doing the harder thing when it’s the right thing, is one of the most expensive parts of your brain. When you’re starting to get hungry or tired, your frontal cortex doesn’t work as well. This is exactly why we have less regulation in the evening than in the morning. This has also been shown in Alzheimer’s patients. In the morning, it’s much easier for Alzheimer’s patients to remember their names than in the evening. This is because our blood sugar levels drop at night and the brain is tired, which explains why the frontal cortex doesn’t work as well.

So now, after a long-winded introduction (and some very interesting food for thought, no less), I’m bringing us back to the initial question. Why is it that when we’re ill, we feel worse in the evening? My answer would have fallen somewhere along the lines of the above. Because of a drop in our blood sugar levels in the evening, we’re just not as good at fighting off infection. But is this true?

The circadian clock & your immune system

Back to my fancy ear infection. After doing some research on the interweb, it seemed that it doesn’t really have anything to do with blood sugar levels apparently.. According to this research, your body’s circadian clocks, which regulate your sleep, are actually responsible for managing your immune system. Because of this, your immune system actually gets activated in the evening. The spike in its activity is what’s helping your body fight off infections, and it does that by releasing a variety of chemicals that can induce inflammation in the infected tissues. The resulting inflammation is what causes your symptoms to flare up, and this is not unusual for illnesses like the common cold, the flu, or a stomach bug.

But… the mind is still a powerful force

Importantly, the mind still has a little bit of an effect on your (perceived) pain level. According to this article, distractions can still have a bit of an effect on the way we perceive pain. When you have work, or TV distracting your attention, it becomes much easier to ignore your pain or headache.

I find reading and writing about this quite therapeutic, because for the past week I’ve done not much other than whine and moan about my ear 😂 Knowing a bit more about what my body is doing interestingly helps me feel better about the pain — you know, shifting perspectives and all… (lol. Who am I kidding).

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