Rethinking the 10 Percent Rule for Increasing Mileage

For the past five weeks, I’ve experimented with a training schedule that’s entirely new to me, with great success. It’s simple:

  1.  Run every day.
  2. Start with just 20 minutes each day.
  3. Each week, increase the length of the daily run by 10 minutes.
  4. Do less when you need to, but not more.

(So far I’ve used Rule #4 only twice, running for half an hour on days when I should have run 50 and 60 minutes. It was largely due to time constraints, but I think that rest did me well.)

Why these rules?

This certainly isn’t the most efficient way to train — for that, you’d want long runs, rest days, and varied workouts.

Instead, I’m doing this as a way to get reacquainted with running, after a two-month layoff following the Rock n Roll USA marathon. I thought of all the things that had kept me from running consistently over the past few years, applied some rules of habit change, and this was the outcome.

To say the new plan has worked is an understatement. My enthusiasm for running has been completely renewed; I’m devouring running books, dreaming big about races, and for the first time in my life, genuinely looking forward to my run each day — for its own sake, not just for its role in a training program.

This has partly to do with the way I’m running, but that’s a story for another post.

But what about the 10 percent rule?

In terms of the 10 percent rule that runners are so fond of reciting — “Never increase your mileage by more than 10 percent each week” — my plan that has worked so well appears completely backwards.

The jump in the second week, from 20 minutes each day to 30, represents a 50% increase in mileage. Then, to 40 minutes, it’s a 33% increase. Even tomorrow, when I jump from 60 to 70 minutes per day, it’ll be a 17% increase.

What’s more, the 10 percent rule will fail on the back end, too. At some point my increase of the run length by 10 minutes each week will become unsustainable. I have no way of knowing when that will be, but I’m guessing it’ll come in another month as I approach two hours of running each day — precisely when the amount of each jump dips below 10 percent!

There are two lessons here.

First, the 10 percent rule doesn’t apply when you’re running below your baseline.

Your baseline, as running coach Jason Fitzgerald puts it, is the mileage level where you’re comfortable but not struggling. Even if you haven’t been training recently, you can estimate it based on your history and what mileage has met that criteria in the past.

Until you reach your baseline, you can increase mileage more aggressively, as I have. I’m approaching mine now, but because the intensity of my runs is very low as I’m focusing on rebuilding the aerobic base before taking on harder workouts, I’ve still got some room.

If you’re a beginning runner and don’t yet have an established baseline, the 10 percent rule still isn’t of much use at the outset. Check out Jason’s post railing against the 10 percent rule for more about why.

The second lesson is that the 10 percent rule doesn’t apply when you’re at the upper end of what you can handle.

For example, let’s say I get up to 85 miles per week with this new plan, exceeding my previous peak by 20 miles or so. I’d be thrilled to get there and I think it’s possible. But at that point, a 10 percent weekly increase will mean close to 9 miles.

In other words, just a month after hitting the extremely high level (for me) of 85 miles, I could “safely” get to over 120 miles per week if I naively followed the 10 percent rule each week.

As optimistic as I like to be, that just ain’t going to happen.

(This isn’t to say my 10-minute plan will be any better than the 10 percent rule at that point. I designed it to help me get started again; if I get to 70 or 80 miles I’ll need to adjust the plan and start spending more time at each level.)

Ending the tyranny of 10 percent

I’m not saying we should throw out the 10 percent rule entirely. For most of the running we do, in a mileage range that’s moderately challenging, it’s not a bad rule of thumb.

But most people pay attention to the rule at the beginning of their training, perhaps when they’re returning to running after a layoff like I am. And that’s the wrong time to abide by it.

Listen to your body as you increase the mileage up your baseline, and then follow the 10 percent rule from there. Once you near the upper edge of what’s comfortable, it’s back to listening to your body for the signals that you need more time or that it’s okay to proceed.

And speaking of listening, that’s been the focus of my workouts during these past five weeks of the most enjoyable, relaxed running of my life. More on all of that in an upcoming post.

Have a great week of running!



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  1. I find that now that I have been running for 6+ years I can increase more quickly after a break too without injury. I think your body knows what to do and can adjust. Thanks for putting that out there!

  2. I agree completely with Fitz’s point on understanding your baseline. I’ve come back twice from injury and had the debate with other runners over the 10% rule in both cases. My challenge to them was always “how to you define the starting point for 10%?” For example, I started back up on a Wednesday this time and ran 22 miles the first half-week. Does that mean I should do no more than 24 the next? No way, both because this wasn’t a “week” to begin with, and my base before injury was in the 60+ mpw range. I think your first step needs to be to find what is “just easy enough” mileage and then start applying the 10% from there. Now that I’m back to 50+ miles per week, I’m applying the concept a bit more rigorously.

  3. There’s actually a lot of talk recently about the 10% rule and how it’s really a made-up number – no real science to back it up. I trained for my last marathon ignoring that rule and had great success. This is where having a coach is so helpful, because they can help figure out what works for your body instead of the generic “rules” that might not make sense for you. 🙂

  4. Interesting, thank you!

    I am trying a similar thing but with 3:1 min intervals. I will tell you how it goes!

  5. The 10% rule is one of those general rule of thumbs that keep new runners from overdoing it. That’s really all its for. I always applied it to a single run on my schedule, either my long or medium run. With so many books and free plans out there, it’s almost useless these days.

  6. Jon Weisblatt says:

    I love it! What can go wrong when you listen to your body?

  7. Could the new scenery and cooler mountain temps be helping just a bit?

    I think maybe I’ll try your method. After two pulled hamstrings and two months off I ran 9 days ago for the first time. If I only go up 10% from that 1.22 mile trial, it’ll be weeks before I am up to a 5K. ummm…no.

  8. Heya,
    Thanks so much for your awesome site. I have it as my home page with intention to sit and read, but must admit when I get in front of the dam computer i want to be quick, so I havnt – even though its been there for over 5 months!!! lol
    I was running 45-50 mins a day (8 ks of hills with toddler in pram haha ) and hit a point where i was constantly hungry, maybe the change to cooler weather didnt help but I was eating a lot and never satisfied. I also had big sugar cravings, which I had never had before.
    After 3 months of toning up I then blew out in a month and got back to where i started, as far as weight gain. Much to my disappointment. I am probably fitter, but do you have any suggested readings on this blog in ref to?
    I have abandoned my daily runs to try and get my appetite back down. Which seems to have helped.
    I have Thrive but was disappointed with the meal planning section and think its just from not fueling my body properly. At one point I thought maybe I was lacking something nutritionally (amino acids??) and my body might have been fed but was starved for whatever i was burning?
    I just purchased this meal plan
    And thought maybe if i start from scratch again with focusing on m food and really planning it I might be able to get back into it.
    Anyhow, thought i’d throw it out there to you and see if you had any words of wisdom to add 🙂



    • Were you breastfeeding at the time? When I’m breastfeeding (off and on for the last -gulp!- eight years!) I have a set weight that is just going to be. I try to just eat what I want and not try to diet, because I’m going to be 175 no matter what. I do run and feel that it keeps me more slender and muscular rather than just packing the fat on!

  9. I prefer Jack Daniels rule of 3-6 weeks of training at a given level of intensity before increasing it by 1 mile per workout in a given week. So if you run 4 times a week, you can increase your total mileage by 4 miles after 3-6 weeks (depending on when you feel comfortable).

    I’m not a fan of the 10% rule – it increases mileage too quickly (especially for fairly new runners) without them getting used to the given mileage first. Part of it is because its assumed that “no more than 10%” means “10%”, not “5%” or even less.

  10. miriam Reeders says:

    hi Matt
    First of all: thank you for your brilliant website, you’ve got a huge fan in the Netherlands 🙂
    I’m enthousiastic about the running every day approach and like to try for myself but i am wondering:
    what about the variety in training? hills, speedwork, intervals, (how) do you plan them? Thanks in advance


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