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Team Interviews | 08.01.2022

Glucose Biosensors: A revolution in cycling or exaggerated hype?

Do glucose biosensors and trackers actually deliver what they promise? Is the current hype surrounding them exaggerated? In our interview with Dan Lorang, Head of Performance at BORA - hansgrohe, we try to get to the bottom of this phenomenon.

More and more, photos of small white dots adhered to the skin of different athletes are popping up on social media - glucose biosensors. Feel better, perform better and regenerate faster. These are just some of the promising marketing messages going around. However, how beneficial is tracking one's blood glucose levels, and can conclusions really be drawn about performance or the quality of training?

"Basically, the first thing to say is that these trackers come from diabetes research and are used very successfully there. For people with diabetes, it’s a great help to consistently keep an eye on their blood glucose levels. So in that respect, these trackers are indeed welcome and very useful," says Dan Lorang. However, the question then arises as to what extent diabetics and top athletes are comparable, or what insights can be derived from blood glucose level measurements that can be useful in training and competition. 

In this case, the UCI was quick to take the step of banning trackers during races. During training or times of rest, however, measuring and tracking is permitted. Lorang is sceptical about whether collected data can be used to draw conclusions that are relevant to performance: "Among other things, it is envisaged that measurements in training will reveal individual blood glucose zones in which the athlete can optimally perform. In the best case, the athlete should then consistently move within this zone. The crux: During exercise, the blood glucose level of top athletes remains fairly constant and slowly decreases with the duration and intensity of exercise. The body attempts to proactively avoid swings that are too large. Therefore, any spikes when consuming a carbohydrate drink, for instance, are generally short-lived, and the body is quickly able to re-establish a more constant level. In principle, the better the body is trained, the more stable the blood sugar behaves.

What becomes very recognisable is a significant drop in blood glucose levels and therefore the threat of hunger pangs. However, this should really never happen with professional athletes in any event. Thanks to sophisticated feeding strategies during races, incidents such as hunger pangs are a thing of the past. If the athlete's feelings and actual reality do not match, the sensor can help him or her perform an internal calibration and bring feelings and reality back into harmony.

So are the devices useless in the realm of competitive sports? According to Lorang, the measurements do have an indirect effect: "It’s definitely the case that athletes can be made more aware of the topic of fuelling. If you’re always checking your blood glucose level during training, you automatically pay more attention to the correct energy intake. The differences and effects of particular foods can also be recognised more easily. I’ve already worked with these systems with individual athletes before. It’s more that we’re able to promote self-awareness than being able to draw significant and valid conclusions about training and performance. At the moment, after a short test phase, most athletes have left it behind relatively quickly."

However, the most meaningful conclusions are most likely to be seen in the area of recovery. "Blood sugar levels also react to stress and mental strain. If athletes fail to devote enough attention to regeneration, spikes in blood glucose levels will become noticeable. It’s possible to create awareness among athletes to pay more attention to their regeneration, which is a very important issue! Furthermore, over a certain period of time, it’s also possible to see which regeneration measures are helpful, which nutrition strategies make sense and how much sleep the athlete requires as a minimum. Yet to be fair, it must be said that I would also see these findings through regular HRV measurement," says Lorang.

For the moment, the benefits of blood glucose monitoring for competitive sports are somewhat limited. However, for the future, such technologies could very well provide beneficial insights for sports scientists. "If you can then use these sensors to continuously measure lactate levels within the blood, for instance, which should become possible, then these measurements could become an absolute gamechanger," says Lorang, highlighting the potential of the underlying technology in the world of elite sports. "This would mean a big leap in terms of training and load regulation, as we saw in the late 1990s with the move from HR measurement to power meters."

All in all, it remains to be seen in which direction this will go. Despite intensive marketing efforts by manufacturers, the technology still seems to be overrated with respect to competitive sports. 

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