I've previously written about the significance of non-intrusive glucose monitoring, and what that would mean for both diabetics and non-diabetics. It's rumoured that Apple is working on it, and will likely tie it into a future model of the Apple Watch. Unsurprisingly, the Apple Special Event yesterday morning came and went with no mention of blood glucose monitoring in the new Apple Watch Series 3, which means it's at least a year away, if not two.

I couldn't help but notice that at WWDC this year there were many nods towards insulin delivery and blood glucose level tracking in the Apple Health app. It was even mentioned in the "What's New in Health" session.

This shows, at the very least, diabetes management is something Apple is interested in. During the Apple Watch section of the presentation yesterday, Apple played a "Dear Apple" video highlighting many different ways in which Apple Watch has enabled its wearers to lead healthier lifestyles. You can watch the full video on YouTube.

I was particularly interested to see that the father of a young girl with diabetes was one of the narrators of the video. Around 90 seconds into the video, we hear this man read part of his letter aloud. He says, "Dear Mr Cook, our daughter was recently diagnosed with type 1 diabetes." He continues 19 seconds later, "The integration of her glucose monitor with the Apple Watch lets us make sure her blood sugars don't go to dangerously low levels."

A few moments later, Jeff Williams took the stage to announce an improved heart rate monitoring app in watchOS 4. The new version of this app wasn't in any of the betas, so it came as a surprise. This app gives more detail and new measurements such as resting, and post-workout recovery heart rates. This kind of fundamental analysis makes the heart rate monitor on the Apple Watch more useful to more people, as you no longer need to rely on third-party apps to analyse the data. It's also useful coming from Apple as they're able to do more than third-party developers used to be - such as keeping the heart rate sensor on for a few minutes after a workout to get an accurate indication of a wearers recovery heart rate. They're also providing a complication to show the latest heart rate data, as well as offering notifications for abnormal heart rates. It's an important update, which I have no doubt will save lives.

After thinking about it some more, I realised it's precisely the kind of app you'd need to make if the Apple Watch was to monitor blood glucose. There would be no point to a watch that measured blood glucose without having a way to display that data back to the wearer. Furthermore, for it to be truly useful, it would need to have the ability to send the wearer a notification if their blood glucose reached a level that was either too high or too low. In the middle of the night, this could prevent a person with diabetes from having hypoglycaemia. The features added to the heart rate app translate almost perfectly into what I'd expect an app for blood glucose monitoring from Apple would do. It feels like they're laying the groundwork for something else here.

Of course, nothing is certain until it gets announced. Every "rumour" that Apple is working on an Apple Watch with blood glucose monitoring could be false. However, based on what they've said and done lately, and the direction they seem to be headed in, I'd say that's unlikely. When blood glucose monitoring does come to the Apple Watch, it'll be reassuring to know that Apple has thought long and hard about it, and is ready to offer a feature that could be life changing for so many people. I'm excited for technology like this to exist, from Apple or otherwise, and if having to wait means the product is reliable when it comes, I'm happy to wait.