I approach this question from a very healthy person's standpoint. This will make you understand how training works. If you eat well, sleep well, hydrate well, live properly with minimal chemical and minimal radio signal exposure and much more, you do not need that many days off actually.

Many professional athletes often take one full day off a week ! That is a lot of lost time during a year. World record holders and champions like Kipchoge, Farah, Jornet and others, have no days off ! The more you practice, the better you become at your sport !

There is a reason for those regular days off and mostly skeletons hidden in the closet. That can be lifestyle factors, bad training habits, bad periodisation or bad technique. For instance the lack of proper warming up and cooldown. I already explained this in another article. Warming up for a runner, is not a 15minute jog ! Nor a cooldown is a 5minute jog/walk with 2minutes of static stretching.
We also can see bad running technique of hammering the heels to the ground. The way we run is with a nice high cadence, forefoot, effortless running style. Leaving the body with little impact, letting the breathing and stabilising muscles work properly. Try looking at the body of powerful forefoot runners and lazy heelstrikers, when decades are behind them. Running builds leanness and a stringy, strong, powerful body. Jacking your heel-bone to the ground for years however destroys bone density, joint cartilage and muscle strength and posture too. After a week of damage, for sure you just want to lay on the couch. After a week of running, you should be feeling stronger and more energised !

Periodisation is one of the most crucial aspect of your training. The flexibility in it too ! When a workout is easy, it is easy. When it is hard, it is hard. Running four zone 3 sets, and five zone 4/5 sessions in 6 days is not how it works. Keeping most of your workouts in zone 1 and low zone 2 is key to performing well when matters and the actual real key for having breakthrough workouts.
That doesn't mean going for 70minute jog at 6:30/km pace. This leads to nowhere ! A 90minute workout can contain actually loads of mobility, enormous amount of skill work, accelerations and much more, with not more than 10minutes of constant running it. Yes a runner should learn and self develop to build a routine, a pattern and a habit !
I often hear: "- But I just want to run ! I don't want to do that crazy shit around it. " I say if you just want to run and not willing to invest into your body, I understand it, just please do not ever complain to me about your injuries, pain, knee operation and so. I don't want to hear it and won't listen !

As training goes, a complete day off with zero amount of work and zero obligations are good ideas like every 3 weeks. Did you hear how I said ? With zero obligations ! If you were forced to take a no-workout day, because of travel, business meeting, family obligations and so, no, that was not a day off. Maybe it even contributed more to your overall fatigue, than a proper run. You'd better gone for that 5 x 6sec hill sprints early before all your duties.

We can also see some other run-environment factors coming into the picture, what might force you to decrease the load. This doesn't have to be a day off though. No access to soft surfaces, altitude, bad weather, no running shoes, no money, too many kids, tough terrain, no-time and much more. Zatopek included running in place into his training, in his room, throughout his entire carrier. Barefoot on a clothes, to soften the surface and later on, on a soft mat. The oregon guys can access alter-g and under water treadmills. Others buy spiked trainers or do snowshoe running, but if chosen well and technique is kept, you can even train in military or hiking boots ! At altitude the best training is intervals, especially at the beginning. You can keep up with your training and racing pace, recover and go again. Maybe starting only with 50m dashes, but after a couple of months, you'll be back at full speed soon. I will always be able to find a solution for you, not matter what ! Even if you were in a 4by4 prison cell !

To sum this up

I really advise anybody want to achieve a goal to look at his training, technique, lifestyle, then act accordingly. There is 365 days a year. Loosing 52 of them is just so high. 14.2% high !!! Instead of cutting down 1hour of sleep every day for that 70minute training, just reschedule your life and add back that Sunday workout. Starting with every second one.

Doing a direct translation, you'll be 14.2% more faster, endurant, resistant and smart. It won't be a straight down 26minutes of your 3hour marathon. But probably an easier 2:55 than before. If added back 33 days out of 52, in 3 years you'll be 100days of training more experienced. That is just a very crucial step towards mastering your art !

Periodisation, technique, workout structure, lifestyle !

Excuses vs. Discipline. Willpower, attitude, knowledge !

Running / workout periodisation

When to take a day off ?

When to take a day off ?

When to take a day off ?