Is Blood Glucose Monitoring the Future of Training?

Is tracking blood glucose levels going mainstream? We explore the innovation around live tracking and how it can be translated to athlete performance.


Torsa Studios
Fitness Innovation Tech Training Workout

A pretty fascinating topic that has surfaced over the last couple of years is the use of CGM (continuous glucose monitoring) in everyday athletes. Primarily, CGM technology has been used to provide reliable data to diabetics, enabling them to track their blood sugar in real time, an incredibly important technology for obvious reasons.


These skin-worn, Bluetooth CGM’s now have the ability to provide real-time insights into how the body reacts to different foods. Why is this important? Well, everybody is uniquely different, and how one person reacts may be completely different to another. That’s why there are so many limitations associated with adopting a meal plan, without the data to back it up.


These forward-thinking companies have adopted CGM technology to unlock potential health, fitness and performance benefits for non-diabetics. Atlanta-based company Supersapiens are one of those pioneering the use of this technology, and count former Team GB Cycling coach and king of marginal gains, Sir Dave Brailsford as an advisor.


Essentially, the sensor and app work together to track what impact food choices have on performance. This is the first time that we have been able to get real-time data on these effects, outside of just how we ‘feel.’ The primary aim is to discover the stable and sustainable energy sources that best meet the body’s fuelling needs.


Who is it for? 

There is really two ways you can look at this. From a purely athlete-focused standpoint, this is targeted at anyone dedicated to getting to peak physical performance. Whether you’re training for a marathon or an elite-level competitor, this will help provide an insight into the effect your dietary choices have on performance. Adding to this, I’d even add dedicated amateurs to this list who want to understand and get the most out of their training.


The other side of the coin are people with genuine health concerns. It’s reported that 13% of the UK population has pre-diabetes or undiagnosed diabetes, where in the US this climbs to 37%. A pretty scary thought.


Nonetheless, whatever the end goals, it provides valuable data that can be reviewed and analysed to help make informed nutrition decisions.

blood glucose monitor


Why it matters?

Glucose is the body’s main source of energy, particularly for high intensity exercise. When you eat carbs, your body coverts these into glucose to fulfil your immediate energy needs, and stores any spare glucose as glycogen in the muscles and liver – your main storage tanks for energy.  Once these storage tanks are full, the rest is stored as fat. In another article, we’ll explore intermittent fasting and the effects it has on blood glucose levels.


Your ability to stay lean, energised and perform at your best physically and mentally can be put down to maintaining a stable blood sugar level.


The VP of science at Supersapiens, Federico Fontana, proclaimed that “Based on physiology principles we know that between 90 and 140 mg/dL can be considered a good range to stay in overall, including when you eat and overnight.” Staying within this range, even when eating, would be a sign that the body is working effectively. “Daily fluctuations should move within that range.”

The trouble is there are so many factors that can influence your blood sugar, ranging from how well you slept, stress level, food and drink, just to name a few. Finding a balance requires good food choices designed to stablise the body’s natural sugar levels. Understanding which foods make you spike or give you big drops will help you reduce, or eliminate them from your diet.   





Impact on performance 

Having this real time data on how your lifestyle choices are affecting your blood glucose patterns, you can start to manage your peaks and troughs more effectively. When it comes to performance, especially if you’re an endurance athlete, you’ll be able to understand what carb-loading foods help fill your glycogen tanks before your race. Or which mid-race snack helps keep your blood sugar sustained and constant, avoiding any unwanted dips. Even which post-race or training session meals best replenish your glycogen stores most effectively.


From a health perspective, monitoring your glucose levels certainly will help with your overall health. High glucose levels will trigger an inflammatory response of some sort, and exposure to high levels of glucose can lead to weight gain, prediabetes, Type 2 diabetes and chronic inflammation.


User testing


I’ll be handing over to Seb here, our founder, who actually tested the Supersapiens for two weeks earlier this year.


Hi everyone! As mentioned, I got the chance to test out my blood sugar levels over the Summer using the Supersapiens app and Freestyle Libre sensor. For two weeks, I would eat mostly my normal diet to see how my blood sugar levels were, with the added sweet treat dotted in to analyse the effect.


For the most part, my blood sugar remained within the recommended range, although with the odd exception. Sweet potatoes would spike my blood sugar more than white rice for example, which is interesting as they contain less glycaemic load than the latter. This is a clear example demonstrating as individuals, we all react differently.


Nonetheless, the real issue came when I started eating sweet treats. When the opportunity arose to eat sugar in the name of science, I didn’t have to think twice. I have a notorious sweet tooth, so I am able to consume lots of sugar without feeling sick. I almost thought because I never felt bad, or the subsequent low after eating sugar, that I was somehow immune to blood sugar spikes and dips. I was wrong, of course.


The results were pretty damning. The immediate spike after consuming something sweet really put into perspective the impact that high carb foods have on your body. The prolonged spike after eating carbs for an extended period of time (figure 3.0) also highlighted the dangers of a high carb diet.

blood glucose monitor


Figure 3.0* - note that this was a snapshot from the previous day, and therefore 106mg/dL is the following day. It had spiked to 170mg/dl during eating.


Key Points

  • A high carb meal of any sort led to a spike and subsequent dip of blood sugar.
  • Paired with fats or proteins, these peaks and troughs were far more stable, keeping within the recommended range.
  • The way I trained personally depleted my glycogen, but not to the point where they dipped under the recommended 90 mg/dL bottom line. This is likely because I don’t train intensely like you would for endurance, or in HIIT training.
  • Sleep and stress levels affected my baseline levels. Poor sleep and high levels of stress would lead to an increased blood sugar, probably as a result of increased cortisol in the system.
  • Eating meals high in protein and moderate in fat would help my body achieve homeostasis.


I genuinely enjoyed my time testing out the CGM. I definitely don’t consider myself a biohacker, but it was an interesting window into my body’s immediate reaction to foods. I wasn’t able to do rigourous testing around optimizing my training, but next time I test it out, that will be my primary focus.


That’s me signing off. If you have any questions about CGM’s, please don’t hesitate to email me at



Final note


The companies pioneering the use of this technology hope that blood glucose monitors will become more mainstream. For that to become a reality, the price will likely have to come down. It’s currently approximately £130 (€150) for their beginner membership programme, which includes 2 biosensors and use of the app. That’s about 28 days of data, each sensor lasting 14 days.


The technology is undoubtably fascinating, and the insight into your reaction to foods provides a great framework to build from. In our opinion, if you’re not an elite athlete looking to optimise performance in the lead up to an event or race, you should be able to get some really good data within the 28 day timeframe.

In our opinion, what’s just as important is the window into your health. The data provided by a CGM can definitely shed a light on the effects of stress, sleep, and food on your overall health. It may help be the key to tackling any inflammation you might be dealing with, but also the impact your lifestyle choices have on everyday health.