It’s been a while since I last managed to write a blog post and that’s for one main very exciting reason- I’m currently in the process of moving to Singapore!

Obviously, it has taken a huge amount of time and effort to get everything sorted, hence the lack of blog posts, but it’s also giving me the opportunity to do an experiment on something I’ve always been fascinated by – Jet Lag.

I’ve written about the body clock before on this blog. But this time I wanted to see if I could use my understanding of our circadian rhythms to help avoid jet lag when I move to Singapore. A few weeks ago we went on a scoping trip, and the jet lag hit me hard, but it also got me thinking. The first night, after an overnight flight where I only managed a couple of hours of sleep, was fine. I dropped off no problem and slept, pretty much, through the night. I felt pretty groggy when I woke up, but that’s not really surprising considering Singapore is 8 hours ahead, so when my alarm went off at 8 a.m. my body still thought it was midnight.

The real problem came on the second night. I was feeling pretty tired, so I fell asleep fairly easily, but a few hours later I woke up. And I was wide awake. Both my husband and I had the same issue- we were tossing and turning from about 1:30 till about 6 am when we finally dropped off again. So what was going on? If we just thought about the body clock, it should have been getting to sleep that was the problem- remember Singapore is 8 hours ahead of the UK, so when we went to bed at 11 p.m. our bodies thought it was 3 p.m.- not normally a time that I fall asleep! But dropping off wasn’t the problem- it was staying asleep.

This makes sense when you realise that we actually have two systems in our brain that tell us when to sleep. Our body clock syncs up with the outside world so that we feel sleepy when it’s dark and awake when it’s light.

One of the ways it does this is by releasing a chemical called melatonin, at dusk, making us feel sleepy. But of course, when we travel to a different time zone, it takes the body clock so while to catch up. Melatonin is released at the wrong time, so we end up out of sync and that can make us feel really awful. But there is another system as well, which tells us how long we’ve been awake.

This system is based on a chemical called adenosine. When we’re awake, our brain cells are really active- and all this activity requires energy. To get this energy, the cells break down a molecule called ATP, and one of the by-products of this process is adenosine. This means the longer we’ve been awake, and the more energy our brain has used, the more adenosine builds up. This build up increases what is known as sleep pressure- and this is what makes it hard to stay awake after pulling an all-nighter or getting up super early for a flight.

It’s also this system that we trick with caffeine. Caffeine blocks adenosine receptors, meaning that our brain thinks there’s less adenosine floating around than there is. This makes us feel more awake and alert. After my flight, these two systems were, in a way, competing. Because I hadn’t slept much, lots of adenosine had built up, and that made me want to fall asleep. But my body clock was out of sync- thinking it was day, not night. So the first night, I was obviously so sleep deprived, and my adenosine level was so high, that I slept no matter what time of day my body thought it was. My sleep debt had to be repaid. On the second day, falling asleep wasn’t a problem because I was tired- I’d been awake for 15 hours and my sleep pressure was high. But after a couple of hours, the level of adenosine dropped enough for my body clock to take over control. And my body clock was saying “Hang on a second, It’s only 5 p.m. Why are you asleep?” So it woke me up. It wasn’t until 3 or 4 hours later, when my body clock decided it was now suitable time to go to sleep, that I could drop off again.

The important thing for beating jet lag is to get your body clock back in sync with the time in your new home, and back in sync with your adenosine system. Once this happens, your sleep pressure will build up throughout the day, and your body will release melatonin at the correct time. These two systems will work together so you can sleep through the night. So I decided to look into whether there were any ways to speed up this resetting of the body clock- and it turns out there are. You can do it using carefully placed light therapy.

One of the ways the brain knows when to release melatonin is based on light levels. Normally, if you go outside after you get up in the morning, you get lots of nice bright light and that sets your body clock for the day. That makes it easier for you to sleep that evening, as melatonin release will be timed correctly. But when you’re jet-lagged, it’s not quite that simple. Because you have to get the light when your body thinks it’s morning, not when it’s morning in the new country. This involves a bit of working out, but there are calculators online that can help. And it’s one of these that I’m planning on trying. I will try and follow the rules as closely as I can when I arrive in Singapore, which unfortunately means having to stay in the dark until midday on my first day there (I’ll explain why in my next post)! I will keep you up to date with how I get on- and hope that the jet lag is a bit better than on my last trip, all thanks to science.

Ginny Smith is a science presenter and writer. A Natural Sciences and Psychology graduate of Cambridge, Ginny performs science shows all over the world and presents a wide range of science content for the likes of the Cosmic Shambles Network and the Naked Scientists. She is the co-author of three DK Publishing science books and her first major solo work, Overloaded, will be published by Bloomsbury in 2021. She is @GinnyFBSmith on Twitter.

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