Nutrition for the Zwift season

For shorter training sessions of up to one hour, we often don't need to consume energy during the session; energy intake beforehand plays the largest role in the session's outcome. However, if the sessions exceed 90 minutes, it may be wise to start consuming energy right from the beginning. Most people are probably aware of this and likely use a similar approach during long outdoor sessions.

If we instead look at specific sessions that are done indoors, for example a shorter interval session, this typically involves an interval time of 15-20 minutes such as 4x4 minutes. There is no need to take in energy during such sessions. Instead, ensure that you have eaten enough throughout the day. It’s usually quite noticeable if energy intake is not managed well; recovery suffers and your legs can feel a bit mushy already during the warm-up.

If the plan is to conduct a longer interval session, like 4x10 minutes at threshold, or perhaps a 50-75 minute Zwift race, it sets certain other requirements. Here, the time at high intensity will significantly increase the depletion of glycogen in the muscles, and you'll notice a performance decline during the session based on low glycogen stores. To counteract this and maintain high quality during the session, or actually have the energy to win the sprint, carbohydrate intake is necessary.

We recommend consuming 60g of carbohydrates for a session like this. If you're doing a longer Zwift race or adding distance after your intervals, increase your intake to 90g/h; your body will thank you for the improved recovery and your next interval session won't suffer. You can also take a gel about 20 minutes before starting; this way, you initiate carbohydrate absorption in the gut directly and your body is ready when you begin intake during the session.

In the above example, we assume the goal is optimal performance. It’s certainly possible to conduct your indoor sessions without any energy as well; you’ll just be a bit more fatigued and push a few fewer watts.

Performance Supplements

In addition to the intake of energy before and, in some cases, during training, we also have performance supplements to discuss. Above all, this includes caffeine, bicarbonate, nitrate, and beta-alanine. 

Before starting, we recommend an intake of caffeine at 3-6mg/kg body weight. This amounts to about 200-400mg for a 70kg person (to achieve optimal effect, you should ingest it 60 minutes before starting). Our own U Intend contains 250mg of caffeine (one scoop or one shot). Caffeine has an invigorating effect and reduces perceived effort. If you are accustomed to caffeine through, for example, coffee, you may need to go up to 6mg/kg, while if you are not as accustomed, you can do well with 3mg/kg and may even experience negative effects at doses approaching 6mg/kg. Caffeine is effective for everything from shorter intense sprints to longer sessions. However, keep in mind that high caffeine intake will worsen your sleep if taken in the afternoon/evening. So it’s perfect for morning intervals but use it more sparingly in the evenings, perhaps save it for your most important Zwift races.

This is the supplement that, together with caffeine, has the greatest effect on performance. Bicarbonate, or sodium bicarbonate as it is technically called, generally works by increasing the pH in the blood, allowing more “acid” that is produced in the muscles to leave the muscles and enter the bloodstream for processing. This enables us to work for a longer time or at higher intensity above the threshold and push a little harder on intervals and threshold workouts. Just like caffeine affects sleep, there are also downsides to bicarbonate. A well-known side effect from bicarbonate intake is stomach discomfort due to gas development that occurs in the stomach/intestines when something very alkaline meets the very acidic environment in the stomach. So experiment with the dose, which should be at 0.2-0.4g/kg body weight and taken 1-3 hours before activity, or buffered over a longer time. The advantage is that one often has easy access to the restroom when working out in one’s pain cave ;) 


Beta-alanine
Beta-Alanine works very similarly to bicarbonate but still differently. Bicarbonate buffers the pH in the blood so that more “acid” can leave the muscles through (acid goes toward alkaline in a equilibrium reaction, so more alkaline blood can accept more acidic ions). But Beta-Alanine, on the other hand, buffers the pH inside the muscle cell by increasing the amount of carnosine by 50-60% in the cells, which in turn handles the “acid” on site. The recommended intake here is 4-6g/day for 4-12 weeks, which provides performance-enhancing effects during high-intensity intervals where the work duration per interval is 1-4 minutes.

The effects of Nitrate are reduced oxygen consumption at a given workload, leading to increased performance. The effects stem from the nitrate in, for example, beet juice (or nitrate in pure form) which is converted into nitric oxide, which dilates blood vessels and increases blood flow as well as oxygen transport to working muscles. The intake should occur 2-3 hours before activity with acute intake. And for those who are really well-trained, buffering applies where intake can occur at any time during the day for 3-7 days prior + intake 2-3 hours before starting.

Of course, you don’t need to take all of these supplements for all your indoor sessions. But see it as inspiration and something you can test during the winter during hard interval sessions or Zwift races to find your own favorite setup with energy and supplements.

Train hard this winter!