CGM in Cycling – Benefits

By Jiri Kaloc

Why should you care about your glucose levels? There are several cycling related benefits that come from understanding how food and exercise impact your blood sugar. Continuous glucose monitors allow you to do that while training, eating, recovering, and sleeping. Let’s take a closer look.

Optimizing energy use during training and races

If you’ve ever “bonked”, or in other words ran out of energy during a ride, you don’t need much convincing about the benefits of monitoring your glucose levels during a ride. Riding at a  makes your muscles burn a lot of glucose. Every cyclist has between 300-600g of glycogen (stored glucose) in muscles and liver ready to fuel hard training rides or races which is enough for about 2 hours of hard pedalling, depending on your effort and fitness.

When you run out, it can feel like hitting a wall because your body has to switch from glucose to fat. Fats can fuel you for days but only at a very low to medium pedalling intensity. Running out of glucose during a group ride or race can feel pretty awful as you’re unable to maintain your usual pace and get dropped. That’s why energy gels, sports drinks, and carb-rich snacks are so popular among pros as well as amateurs. Generally, cyclists try to get between 60-90g of carbs per hour from food on the bike to fuel their race pace.

CGMs can give you an early warning that you’re running out of glucose and need to eat as soon as possible. They can also help you find the exact number of carbs you personally need. Those who used CGMs say it helped them realize they need fewer carbs than they thought for easy rides, and more carbs than they thought on hard ones. If you make the proper adjustments, your performance in training and racing is likely to improve.

Enhancing recovery

Cyclists often try to stay lean by cutting carbs off the bike to reduce their calorie intake. This can work well in terms of maintaining body weight but it can have negative effects on recovery and health. It’s especially prevalent among female pro cyclists and the number of health issues tied to it are officially recognised as Relative Energy Deficiency in Sport (RED-S).

CGMs can help you keep an eye on your glucose levels to make sure you don’t cut carbs and calories too much. It can be especially revealing to see your glucose levels over night, because some athletes drop to hypoglycaemia, low blood sugar, when sleeping without realizing.

Customizing nutrition

Many cyclists know that rice, oats, or bread are great sources of carbs to include before a ride. Many also heard that they should have a large carbohydrate meal about 3 hours before a ride and a small carbohydrate snack about 60 minutes before. But we are all different and it can be challenging to find out which foods and when exactly you personally should eat.

CGMs will show you which foods elevate your blood sugar by how much and for how long. This makes pre-ride nutrition so much easier. You can truly personalize your nutrition when you see how each meal, snack, and drink impacts your glucose levels. You no longer need to rely on recommendations for the average person.

Improving health

Glucose has a significant impact on health, not just cycling performance. High levels of blood glucose are desirable during a race but dangerous when not exercising. If you have elevated blood glucose chronically, you can develop issues such as diabetes and cardiovascular disease. Stable blood glucose will help keep oxidative stress low and inflammation under control.

CGMs help you understand what combinations of food keep a stable blood glucose and which foods spike it harshly. You can observe in real time how adding fibrous and protein rich foods to a carbohydrate source flattens the glucose curve. Regularly seeing how dramatically sweetened soda and alcohol effect your glucose levels could be enough to make you reconsider when and how much you consume.

With all of these appealing benefits out in the open, it’s time to get into how you can apply CGM in your training and racing.