How long does your fitness last?

Different types of fitness take different lengths of time to build, but they also take different lengths of time to disappear when you don’t train them. Original question: “Quite some time ago the TrainerRoad Blog had an article exactly about this topic, one problem, I cannot find it. Does anyone know to find or have this chart? Detailing the difference between for example VO2max fitness VS general endurance.” Thanks to @IanDarlington for finding it quickly!

The original TrainerRoad source:

Training Residuals:

  • Aerobic Endurance – Establishment: 25-35 days; Residuals: 25-35 days
  • Anaerobic Power – Establishment: 14-22 days; Residuals 14-22 days
  • Muscle Endurance/Threshold – Establishment: 10-20 days; Residuals: 10-20 days
  • Sprint Power – Establishment: 2-8 days; Residuals: 2-8 days

Declines in Aerobic Capacity:

  • 1-7 days: negligible decrease
  • 10-14 days: 6% decrease
  • 14-30 days: 12% decrease
  • 30-63 days: 19% decrease
  • >63 days: 26% decrease

Minimum we can do to stay fast:

  • Aerobic Endurance – Once every 2 weeks, do a long, low-intensity ride. Ride long enough that the fatigue comes as a product of the ride’s duration, not its intensity. Example:Laurentian
  • Anaerobic Power – Once a week. Something along the lines of 30- to 60-second repeats upwards of 130% FTP should suffice. Example: Bird -1
  • Muscle Endurance/Threshold – Once a week. Try a 2×20-minute Threshold or even Sweet Spot workout. Example: Eichorn
  • Sprint Power – Once a week. Perform 4-6 all-out efforts somewhere between 20-30 seconds long. Example: Bays



This one I think: How much training volume does it take to maintain ~3w/kg?


Ah yes thank you! I remember seeing this way longer ago but I guess it has been sourced multiple times.

I can now either delete this topic or keep it as a Training Residuals resource place. Let me know what you guys think.

There’s loads of stuff on the internet about detraining and what happens to your fitness if you stop.

I now have a second question which is, what constitutes the fact that you can regain past fitness much faster than it took to get it the first time?

Muscle memory? Because you don’t lose 100% of fitness? :man_shrugging:

Part is mental. It’s easier to attain a level of fitness you have already obtained. You just know you can.

Part is physiological. Exercise related angiogenesis is not 100% reversible even after detraining. There is always some residual increase in capillary density. Same with mitochondria size & density. There is always some residual increase that remains even after detraining. For sure, detraining leads to decreased capillary density and decreased mitochondria count but it’s still materially above a ‘virgin untrained’ state.

I personally believe that there is residual muscle recruitment learning that does not detrain or does not detrain quickly.