Indoor vs outdoor

Are you technically not training to your fullest potential when you’re training with lower power but high exertion (wrt HR) indoors than higher power higher exertion outdoors?

According to my very minimal knowledge there are two parts contributing to ride a bike. The cardiovascular and the muscular. Do you muscles get trained in a specific way at higher power output than lower output keeping the cardiovascular aspect of it almost same.

  • my ftp is 40-45 watts different from outside to indoors. Power source : powertap P1 both cases
    *also my HR is comparatively around 10BPM lower indoors.

In general, yeah. Keep in mind that heart rate rises in response to a lot of factors that have nothing to do with the strain you’re putting on your pedaling muscles: heat dissipation, life stress, caffeine, tiredness… but a lot of the things you are trying to train involve changes in the muscles themselves in response to the strain they experience: muscle capillary density, mitochondria count, and mitochondria size for example.

I hate to sound like a broken record, but usually the #1 difference between indoor and outdoor riding is air flow, which has a massive impact on evaporative cooling, which aside from affecting your heart rate generally has a big impact on your core temperature and your ability to push hard - especially for long efforts - that you need for FTP tests.


Can you explain how you came to the 40-45W difference?

1 Like

This is a pretty big discrepancy between indoors and outdoors. What is your fan situation like when training indoors?

  • It’s important to note that roughly 75% of your energy consumption on the bike goes toward thermoregulation. That leaves 25% of your energy left to turn the pedals on your bike.
  • If you can minimize the energy your body spends on cooling, the more energy you’ll have to push the pedals (effectively raising your FTP)
  • We’ve had great luck with the Lasko Blowers. We find that they are able to produce a much higher velocity wind than a typical fan, which significantly improves the evaporative cooling while training indoors.

Motivation can also play an important role when riding indoors. Watching cycling races or other exciting stimulation can help you reach those higher targets when training indoors :muscle:


I could hold good power with the wahoo bolt as my main device without trainerroad. Maybe I’ll try doing a trainerroad like workout on the wahoo and see if im having problems on the software. Seems unlikely though but i feel there’s a small chance after today’s workout. 320 watts 30x30*5 of 4 sets was unimaginable on TRR.

We don’t manipulate the incoming data in any way, but rather we simply record the data that we receive, same as the Wahoo Bolt. Therefore, there should be no difference between the two data measurement methods.

That being said, if you suspect there may be some software issues that are making your workouts harder, our Support Team would be happy to investigate this issue just in case :+1: You can reach them at

1 Like