Science of Rest

Hi TR forum!

I have a friend who is insistent on never taking a full rest day, rather he’s of the opinion to always do something light vs a full day off. I kid you not, he has not taken a full rest day in over 2 years.

Could someone link me some research on why a full day off is more beneficial than just having a light day?

My intuition is that given the choice between either a full rest day vs having a light day, a full rest day is more beneficial given that light stress is still stress on the body.


But that light stress might not be detrimental or damaging.


Also depends on how hard his hardest days are. If he’s one of those “I must post something to Strava everyday” types that does a 30km ride and has a coffee then riding daily is no big deal. If he’s doing races or workouts to absolute exhaustion, then doing a 100km zone 2 ride the next day, then max efforts the next, I’d argue the point of having an actual rest. A lot of the podcasts hammer home the point that most go too easy on hard days, and too hard on easy days, making a pretty flat curve. The need to ride daily and/or post something to Strava seems quite unique to MAMILs/Masters riders.


I don’t have any research, but I think you can test much of it yourself. For example, last season I was on a MV plan, i. e. Mondays and Fridays were rest days. I had a group ride buddy for a light Friday workout (endurance workouts like Carter). I just couldn’t sustain that.

This season I created a MV+ plan, which extended all workouts by adding Z2 workouts and upping the difficulty levels. This seems much easier than adding a simple Z2 workouts on Fridays. I really look forward to my two days off, mentally. I can sleep in, I can just relax, knowing I have done my work for the day. The next day I am ready for the next workout with plenty of enthusiasm to spare.

Now I still commute every day by bike, and I do that in Z1, Z2 max. But it is only 4 km one-way, so it doesn’t add much effort.

Coming back to your buddy, it all depends what “light” really means. If that means 30 minutes at Z1, I guess that’s not much of a problem. But personally, I don’t think that sounds sustainable — especially once you think Z1 spins are mandatory.

No science, but just a couple of thoughts.

  1. I find having a full rest day helps with motivation to do the coming hard days
  2. If there are any overuse injuries developing under the surface, then a full rest day is a chance for them to resolve themselves before they rear their head in the middle of an important workout

Taking this to extremes, we have examples like Amanda Coker, so we know you can operate within a certain power range daily even without rest.

We don’t know if for example Amanda would have gained more power had she taken the occasional rest day or light rest day.

It’s possible that at some point she never actually got any fitter, but that may also be the case even if she had rest days.

Like the guys above, would really depend on what sort of riding your friend is doing, and what the light workout is, and even then we don’t have a study to hand unfortunately for someone who has been doing this for a year or more. Unless he has FTP tests and a workout history to share - that would be interesting!


There is a skill in riding easy, that many seem unable to acquire (maybe ego?), and as a consequence it is safer to prescribe a rest day.


You haven’t said what his objectives are and whether he is trying to train and if so for what outcome. It’s quite possible to ride everyday for long periods depending how much each day taxes you.

Somewhere near the bottom end of intensity it gets a bit hazy of what is “training” and what is “normal life activity”. Some people say they’re always training, while others claim to never train at all. What’s the difference in terms of stress between a 2x 30min easy ride to the cafe vs a 2 x30 min commute to work?

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My N=1 experience:
I haven’t taken a rest day in 2+ years now. Every day, I either cycle, run or swim (I rarely only swim in a day, especially for the last year).
My easy/recovery/rest/callitwhatever day is a very easy 1-1.5h ride or run. I do not feel exhausted in any way, shape or form afterwards and I could argue that I even feel better than before: refreshed and mentally more focused, since I cleared my mind during the exercise.
I’m not saying it works for everyone, but it sure works for me.


You won’t find any such research.

The science supports that working out is not recovery, it is training stress no matter the load or zone or whatever. Recovery time is only needed when there is stress to recover from.

So the question is not rest day vs light training, it’s a question of how much stress/damage/fatigue you’ve created and how long you need to recover and will naturally therefore vary.

How much and how hard are you training, sleeping and eating?

N=1 and highly subjective, but I found I was able to ride 7 days (all on trainer, no coffee rides here) while I was focusing almost entirely on endurance/tempo. Towards the end of the 2.5 month block I was starting to tire, and as soon as intensity showed up the wheels came off. Now I take Friday’s off, and I’m much better for it.

Does that mean your friend should take a day off? Why don’t you let your friend train the way they want to? You seem to be on quite a crusade to prove them wrong, maybe they have other reasons they’re training 7 days/week.


(not necessarily endorsing it; personally, if I don’t feel the need for a complete day off I probably don’t train hard enough)


This caught my eye.

“one of the few examples is a 2014 study of half-ironman triathletes, which found that faster athletes took fewer rest days Of course, we can find a much larger body of literature pushing athletes to the breaking point with workout strain and relatively little recovery that documents all the debilitating outcomes of over-reaching and over-training.”

If there IS such a “large body of literature”, why didn’t the author cite even ONE study?


Personally, I find it better to stick to routine than take a full day off. When weather allows, I normally go for an extra walk (in my “workout” slot), or if weather doesn’t allow a version of recess. My training is “me” time, so as much as the routine a bit of headspace

A lot more factors than just “on the bike” that come into play for recovery/ doing too much. NEAT, sleep, nutrition, work stress*, life stress*. *the bike may be a break from these.

But ultimately, it’s your pals N=1. Doesn’t matter what you, or us, think.

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I find if I take a rest day then the next day I feel awful (which on a MV plan coincides with a hard workout)

Therefore on Monday’s I do Lazy Moutain -3, next day I feel great.

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I never take a day off unless forced (travel, etc), which is rare.

But my “easy days” are actually easy days. My commute this morning (about an hour) was all Z1 or below HR. I feel no stress from that. I did a 220 TSS race yesterday.


Some people will be fine, but some will also get chronic injuries not taking a day off…pretty much the simplest answer. How much do you want to find out which group you’re in? Haha

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Amateurs are notorious for not resting enough