Cyclists are using Nix Solo year round, but consistently the spring and summer months show the highest number of logged cycling workouts for both men and women. Nationwide, the spring season boasts more moderate temperatures allowing for more comfortable long rides. In the summer months, there is more consistently warm weather with less rainy days disrupting training plans. Increased vacation times also contribute to the additional rides logged. Furthermore, summer is often the peak season for cycling races so it’s natural that Nix is incorporated into athletes’ training regimens.
While warmer weather encourages more workouts, the hotter weather can also pose challenges for hydration. Most cyclists will opt for early morning or evening rides to mitigate these conditions. Regardless of the time you are out on the road or trail, getting a pulse on your hydration needs is an area that Nix consistently assists users with.
Each workout includes a Nix Index value between 1-100, which is a score of the current environmental conditions, taking into account temperature, humidity, dew point, wind speed, solar load, and altitude. In short, the higher the Nix Index, the more heat the body will produce and the more fluid loss you are likely to experience during your workout.
Not surprisingly, the data shows that as the Nix Index rose, average hourly fluid and electrolyte loss rates increased as well. In other words, as the environment got hotter and more humid, athletes sweated 6-15% harder. This equates to roughly 10% more sweat for each 10 point increase in the Nix Index.
Electrolyte needs follow a similar pattern, rising as the Nix Index increases. While not linear, electrolyte needs increase approximately 16% with each ten-point increase of the Nix Index. So, a user that loses 800 mg of electrolytes an hour when Cycling with a Nix Index of 60 will need ~1245 mg of electrolytes during extreme heat workouts. That’s 445 mg more electrolytes - slightly more than one-third of an LMNT packet.
Many cyclists may overlook their hydration needs for an indoor workout given the proximity to a water source, lack of exposure to potentially more extreme outdoor conditions, or ability to stop at any point (vs. on the road far from home), but viewing the data on fluid and electrolyte loss needs for indoor workouts revealed some surprising insights. Our data shows that average hourly fluid and electrolyte losses for indoor workouts often results in higher loss rates than an outdoor workout in the most extreme conditions. On average, indoor cycling workouts are very close in comparison to outdoor workouts with a Nix Index of 90 or above.
This is likely due to the lack of, or significant reduction in, wind convection during an indoor workout - even when using a fan. During any given workout, when body temperature rises, the body searches for a way to cool down, triggering sweating. When cycling outside, the forward movement produces wind convection that promotes sweat evaporation and cools the body, resulting in a decrease in sweat rate. Even with a fan, the wind convection is lower than that typically produced by a 17-21 mph ride. Additionally, all the heat dissipated from the body is retained within the room. Without the same level of wind convection, sweat rates will be higher in order to maintain the same core body temperature.
For cyclists, hydration needs will vary significantly based on environment and location. The data shows that sweat rates and electrolyte loss rates during indoor workouts are comparable to the most extreme outdoor rides. This means cyclists are losing just as much sweat in their indoor training sessions as they are in their hotter outdoor workouts.
To review how your sweat data aligns, filter your workouts in the Nix app by Nix Index and by location.
Do you have a hydration topic that you want to see us cover? Send us a note to info@nixbiosensors.com and we’ll add it to our list of upcoming article content.
Data for this article was compiled based on activity type (cycling), location and Nix Index for workouts from September 2023 through week one of July 2024. This data range was selected to ensure all workouts included the respiratory model which was introduced in August 2023. Only workouts of at least 45 minutes in length are included within the dataset.