The corona virus has changed the way many people exercise. Many cyclists and runners have resorted to Zwift for their training. Zwift offers an engaging way to exercise safely at a time when outdoor riding or running is unwise and in some countries unlawful. The term social distancing is a little unfortunate, in times when social togetherness is extra important… physical distancing and social togetherness would have been better. I have been an early adopter of Zwift and I like that it offers an opportunity to meet up with friends and socialise in a virtual world. Even more important in these difficult times.

In this blog I want to answer 2 main questions:

1. What are the nutrition recommendations to ride or run on Zwift?

2. How can you use Zwift to improve your nutrition?

1. Nutrition recommendations for riding on Zwift

To start with the first question: how much and what should you drink and eat when riding or running on Zwift? The only correct answer is: it depends.

Firstly, it depends on your goal. If you are just riding and performance is not important, nutrition is also less important. If you want to race or challenge yourself, nutrition will become more important.

Secondly, it depends on the duration. If you are doing less than 45 min, don’t worry about nutrition. If you are doing 2 hours or more and it is pretty hard, nutrition will help you to maintain power or running speed. Even sessions that last about 1 hour can benefit from regular small sips of a carbohydrate drink (Read more about this here: Update on carbohydrate mouth rinse studies). The recommendations are not different from riding or running outside (For more detail see Carbohydrate recommendations during exercise). The infographic above has an overview of carbohydrate intake recommendations. In general, liquid formulations can deliver carbohydrate faster but gels are good to and solid foods, as long as there is not a lot of fibre, fat or protein can work as well (see a more detailed discussion her: What is better: drinks, gels or solids?)

Especially on the bike, for many, sweat rates will be slightly higher, because cooling wind is much reduced compared to riding on the road. As a result, body temperature will increase much more rapidly, and sweat rate will be higher. This means fluid requirements will be slightly higher too. The best way to check whether you are drinking enough is to step on the scales before and after a session. If the difference is less than 2-3% you drank enough. If your weight loss is much greater than this, you should probably be drinking more. Often you read that you need to drink the same amount as you sweat. This is not necessary (and also often impossible).

2. How can you use Zwift to improve your nutrition?

Zwift is a great way to improve your nutrition on race day. There are 4 main ways you can use Zwift to prepare for races. First you can use it to personalise your drinking plan by establishing your sweat rate. Everyone sweats differently and therefore drinking plan must be personalised. The second way is to practice your race nutrition plan and related to this is also 3, training your gut. Let your gastro-intestinal system adapt and practice what you are planning to do in a race day several times in training. Finally, if you are going to compete in hot conditions, heat acclimation is essential. If you are not living in a place with similar conditions, you will have to simulate these conditions at home. Now lets discuss these 4 areas in a bit more detail.

a. Estimate your sweat rate

You can use Zwift to get a better idea of your sweat rate. Make sure your session is at least an hour, and at an intensity that is somewhat comparable to your race intensity. Simply measure your body weight before and after the session (ideally nude body weight), measure the weight of your bottle(s) before and after using a kitchen scale, and if you also know the exact duration of the session, you can get a pretty good estimate of your sweat rate. If you are not sure how to do the calculations, please refer to this blog How to calculate your sweat rate.

Not all of the weight loss will be sweat (water) and you may also lose some carbohydrate and some fat, but it will be a good enough estimate. If you repeat this measurement several times in different conditions you will get a really good idea of your sweat rate. If you combine these measurements later with measurements outside, it will become even more predictive. The beauty of doing this on Zwift is of course that you can have bottles and scales ready next to your bike or treadmill.

b. Practice your race nutrition plan

The second thing you can do is practice your race nutrition plan. You may have a plan for your race, perhaps a certain amount of carbohydrate, or a certain number of gels you want to take in. You can simply have everything you want to use lined up next to your bike or treadmill and take these products at exactly the right times. Many are using CORE Nutrition planning (www.fuelthecore.com) to plan their nutrition and get an evidence based nutrition plan that is fully personalised. You can now test this nutrition plan during a Zwift session. If needed you can tweak it.

c. Train your gut

It is highly recommend to repeatedly practice your nutrition plan. When you do this several times you can try to increase the carbohydrate intake and perhaps also fluid intake a little. This is often referred to as training the gut (read this blog for more background). Say you have a nutrition plan with 60 grams of carbohydrate per hour (2 gels plus half a bottle of sports drink per hour). Once a week you could dedicate to training your nutrition where you practice this intake. Starting perhaps with 50 g/h, and building up to 70 g/h, maybe even 8 g/h. If you can tolerate 70 g/h in training, it is likely that you can tolerate 60 g/h later in your races without any problems. Zwift is a great platform to train this because access to drinks and sports nutrition products is easy and you can also easily follow a timeline or a plan.

d. Heat acclimation

Zwift can also be used for heat acclimation. Simply crank up the heat in your pain cave. Maybe add a humidifier to simulate the race conditions even more. Or if you cant heat up the room and you don’t have a humidifier, just layer up!! The most important thing is that yu increase your body core temperature significantly. Ten sessions of 1-1.5h should give you most of the adaptations you need to compete in even the most extreme conditions.