It takes about 2 months to regain 2 weeks of de-trained aerobic fitness

A wise pro coach told me this. I’m not sure my experience supports this assertion.

Anybody think (based on personal experience or extra points for actual research) it’s true that ‘x’ time spent de-training takes ‘4x’ time training to recover?


I know only 2x. But 4x can be plausible when you think about whole process of recovery like simple flu (this is example from Dan Lorang as far as I remember, I can be mistaken but definitely someone from that triathlon show) - 1 week of flu, 1 week of returning to training, 1 week of increasing the load and 1 week of normal training.

And some science:

And some more fun-fact:


nope - dont believe that for a minute and its certainly not been my experience. Its only taken a few rides to get back to where I was after 2 week holidays etc.

When I had a 2.5yr break it took only 6-7 months to be back to where I was before and get my FTP back to within a few watts of 275w at age 48.


Back in August my ftp was around 260, then about 5 weeks off-season. Rough timeline of what followed:

  • Aug 26 tested positive with C19
  • no riding for 2 weeks
  • Sept 13 started super easy recovery spins which post ride were 0.25 IF (using pre-C19 FTP), would eyeball these at a 180-200W ftp
  • another week off at end of September
  • training restart: Oct 4th
  • October 26th, my power at z2 HR was back up to pre-C19
  • Dec middle month, about 12 weeks (3 months) total from back-on-bike to back to where I was before C19

So about 3x full return.

Saturday January 8th I did an 11-min pacing effort in prep for upcoming field test, and power-to-HR would put my ftp around 275. Which brings fitness back to the same level of my peak season of 2017.


I would say there is a big difference between “I had some time off, kept reasonably active” vs “I was ill…Covid or otherwise” in terms of time needed to regain fitness. The former - quite quick …the latter …how long’s a piece of string?


That one is fresh in my mind. I could give another example in 2019 of 4 weeks off the bike, weaker base fitness, and it took a LOT longer to regain fitness (6 months?). Same in 2018 but that year saw a fitness decline after blowing up on TR build. And another example from fall 2017 with shorter off-season and it bounced back almost immediately (couple vo2 workouts). 2020 I lifted heavy after off-season and was so glycolytic that it impacted my ftp for months, hard to draw conclusions from that year. Stronger aerobic base = quicker return to fitness.

I think it depends on what those 2 weeks entailed. I’ve had 2 week periods of low to no training (running in this case) that I bounced back from very quickly. I’ve also had 2 weeks of being sick where after a few months I still was not back to normal. So it depends I think.

Answer to how many X depends independently on each of the below, in different ways:

  1. If detraining includes complete rest, or just reduced volume, frequency, intensity, etc.

  2. Total duration of detraining.

  3. Fitness level in general. Higher fitness will take longer to recoup. But this is also inversely correlated with number 4. Usually high-fitness folks have been fit for a long time because when you’re pushing at your genetic limits, gains are slow, meaning you’ve been hovering around the same fitness forever, reaching for little gains.

  4. Fitness level relative to athletes best-ever fitness. If you’ve been a 5W/kg but you’ve been hovering around 4W/kg since you quit pro racing, then you detrain to 3.6 W/kg, you’ll get to 4W/kg virtually overnight. If you’ve been a 4W/kg at the maximum, then it’ll take a little longer.

  5. Fitness level relative to natural untrained fitness level. If you stepped over a top tube and instantly had a 3W/kg FTP, and you just detrained from 3.5W/kg to 3.2W/kg you’ll get fitness back overnight. If you were a 2W/kg guy upon first riding, and clawed your way to 5W/kg, it’ll take longer to make up the same percentage (or absolute) drop in fitness.

  6. How long the athlete previously held that recently-lost level of fitness. If you’ve been a 4W/kg guy for 10 years, and you detrain for 4 weeks, it’s not going to take even 4 weeks to get that back, in all likelihood, let alone 16 weeks.

  7. Other activities performed by athlete during detraining. Most detraining doesn’t come in the complete absence of training. There is a HUGE difference between no training, and 2-3 hours per week of very very easy training, in terms of maintaining ones fitness. If bed-rested or restricted to very few daily activities with no bouts of exercise whatsoever, there can be greater acceleration of fitness loss. But if you exercise even for 30 minutes a week, there is a lot less detraining than folks usually think and it comes back much faster than the “4x” quote here.

  8. Age. Older = slower. Sorry. But it also means you’ve probably been fit for a long time and maybe even had higher peak fitness back in the day … so it might mean faster for former racers who just kind of race for fun these days.

  9. EDIT/ADD: The method by which fitness was attained. I’d posit, though I have no research to back this up, that fitness attained via high volumes of training may last longer than fitness gained via high intensities of training. But that may be a false assumption on my part, because folks who train with higher intensities all the time tend to have shorter overall training history than those who train with higher volumes, and so it may simply be a training age effect that I’m assigning other meaning to here.

Probably other things too. Those just jumped to mind.

In general, I think it’s shorter for most folks than 4x.

For me it’s probably less than 1x. I train little in the first place, and have occasionally driven my peak fitness up to maybe 3.4 W/kg, so when I detrain to 2.9W/kg from my usual 3.2 W/kg, it’s quite easy to get that back in a week or two. Even on my “detraining” phases, I still go out the door and run a hard mile or some other silly thing to get my HR up for health’s sake.


I tend to agree with @Dr_Alex_Harrison based on my own personal experiences.

I’m currently going on 10wks of full rest, as in absolutely zero exercise due to a broken femur. At a minimum I have another 5wks (next appt) before I get cleared to put weight on my right leg/foot and can begin some type of rehab/exercise. I’m expecting that it will take longer than usual to regain fitness since I am not only detrained, but will have to regain lost strength, mobility, etc., in my right leg as well. It should be interesting, but I doubt it will be fast.


No one will respond the same.

I had a car accident a year ago, I had taken an FTP test two weeks before. I did a full week of gentle spinning only every day to recover, nothing else (no running either, like normal). After that week I did a couple workouts to test my body, then another FTP test and I matched the last FTP.


Would love to know what research says. My guess is that it is the better shape you were in, the longer it will take to regain fitness. Reasoning: Those last few percentage points are the hardest earned and easiest lost; whereas going from couch to, say, 100 EZ miles a week is pretty quick. It takes years of hard training to go from high-level to the highest level; it takes months of training to from low level to mid level.

I think we already answered some of this above but my bit is like this this.

If you stop for a week because life takes over and you travel for works and have lots of stress the detraining is significant.

If you rest and relax and don’t go overboard eating on a two week vacation in mexico then the detraining is less significant.

The ratio is often used as a motivator. To keep consistant and regular training. It has some truth but I set a 400m f/c pb on a saturday after a 70 hour work week where I didn’t see a pool.

Different people react differently to different stimulus

1 thing I can be (personally) sure of is that stress and pressure will eventually effect your training so taking time out, resolving that and coming back will yield better long term results

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Yeah. Probably context is important. The coach that made the assertion was Alan Couzens so it’s reasonable to assume that he is talking about ultra-level endurance and elite-level athletes. I think that makes a difference.

I would say it’s true. I had several setbacks last year and was off for 2-3 weeks multiple times. Always took me 2-3 months to get back on. Unfortunately, then I had to stop again. I am currently about to recover from the last break in November. WKO5 backs that up.

I took a day off 3 years ago and I still haven’t recovered, mentally.


:rofl: :rofl: :rofl:

20/09/20 - got CV19.

Started gentle spins 27/09/20

Back on the bike outside 4/10/20

Fitness back to pre CV19 (per Training Peaks) 22/11/20.

That’s unfortunate. Get well soon!

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