Exploring different timezones by Dr Alex Ryan


Alex-Ryan-150x150A few months ago Holly Rose wrote a blog about going on holiday with Type 1 diabetes, and it got me thinking about the effects travelling though different time zones can have on glycaemic control. Normally the body responds to circadian rhythms, a roughly 24-hour cycle which affects the levels of several hormones, which in turn affect sleeping, eating, blood pressure, heart rate and other factors.

Importantly circadian rhythms affect blood sugar levels; hormones such as cortisol and growth hormones encourage sugar release. Normally these hormones are released during the night when you’re asleep, and insulin is secreted to prevent the levels of sugar getting too high. However, in Type 1 (and Type 2 to a lesser extent) diabetes insulin is not secreted, and problems can occur. Insulin pumps can help remedy this, by delivering insulin 24-hours a day, but as you can imagine anything that disturbs sleep can severely affect glucose levels.

Furthermore, disturbing sleep and meal times can have a profound effect on those who inject insulin, like my Dad. My Dad was diagnosed with Type 1 diabetes when he was 18, and currently uses Humalog Mix75/25; a 3:1 mixture of long acting to short acting insulin. Whilst I’m based in San Diego, my parents are still in Manchester, a full eight hours ahead of me. I figured he would be a good person to ask for any helpful tips he’s been told.

Holly also wrote about travelling to the East Coast recently, but before travelling through five or more time zones it is a good idea to have a chat with your diabetes specialist consultant.

If you don’t use an insulin pump, it is recommended to use a bolus-basal regimen of insulin treatment. This requires several injections throughout the day, usually accompanying meals. This mimics normal insulin release, and importantly allows for flexibility and a high level of control. Travelling eastward generally means a shorter day so less insulin is needed, whereas travelling westward means the opposite. My Dad concurred with this, and used a lower dose when he arrived back in England.

Due to the irregularity in meal times, and potential changes to rates of physical activity the risk of hypoglycaemia is increased during travelling. This means it’s important to check blood glucose levels more regularly than normal. Snacks are obviously important, but slightly less obvious is treatment with fast-acting insulin. This type of insulin has a short half-life, meaning its function is to quickly lower levels of blood sugar. It can be beneficial for flights to help manage sudden increases in blood sugar.

My Dad also recommends finding out approximately what time meals will be. This can help you plan when to have snacks and especially when you take your insulin. He also mentioned that a certain airline takes a long time to distribute food. My Mum’s vegetarian option arrived pretty quickly, so my Dad took his insulin, only to be left waiting for his food. Luckily he’s experienced enough, and my Mum panics enough, so they were well stocked with things to keep him ticking over until the food actually arrived.

The majority of these problems could be history soon though. Xavier Hames, a four-year-old Australian boy, has received the world’s first artificial pancreas. It’s similar to an insulin pump, but has the ability to measure blood glucose levels and alter the amount of insulin it releases. Although it is currently unable to manage hyperglycaemia without user input, it is definitely a step in the right direction, and makes travelling through time zones a lot safer. If you have any questions for me, or my Dad, feel free to leave a comment.

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