Running: How much is too much?

@fitoverfortymom - You've got some good advice, which is notably lacking in numbers quantifying how much is too much. I'd like to talk a bit about why there isn't a good numerical answer to your question.

How much you can run depends on how well developed your cardiovascular system is, and how well developed your musculo-skeletal system is. The cardiovascular system trains to efficiency faster, which allows runners to run themselves into injury. Hence, the common question about how much is too much.

Not only is the musculo-skeletal system slower to develop, it's harder to measure. It's pretty easy to tell when you reach your cardiovascular limits; you simply can't run that fast any longer. The muscles, tendons, and ligaments tend more to give you minor aches and other sensations that you can run through . . . until they become major pain that you can't run through.

Every coach and runner in the world will tell you, "Listen to your body." While I haven't found any better way of saying this, it's one of the most frustrating pieces of advice for the new runner. It's easy enough to listen to my body. The hard part is understanding what my body is saying. Some niggles don't mean anything. Some mean I've trained hard and need a rest day. Some mean I've done too much, too repetitively and need to back off to avoid injury. It's that last kind you really need to pay attention to.

So, how do you tell when a niggle is meaningless or good training sore versus a warning of impending injury? I haven't heard any good way of accurately describing the difference. Most runners I know had to learn by living through injury, and thinking back to the sensations that preceded the pain. I may tell another older runner that I'm backing off from 6 miles to 3 miles today because my right Achilles feels iffy. He says, "You're smart." I say, "I spent a lot of time on the couch learning to be this smart."

As to numbers . . . when I was a new runner, I ran myself into injury on a schedule of 5 days a week, less than 25 miles. It was too much, too soon for where I was then. This week I'm running 5 days and it feels like slacking because I usually run 6 in marathon training. And if I was running as few as 30 miles a week, that would mean I have a serious scheduling problem, I'm sick, or we have a major winter storm preventing me from using the roads or getting to the indoor track.

And that's the problem. Less than 6 years ago, 25 miles a week was too much for me. Two years ago, I recovered from a rolled ankle on 30 miles a week. Now, 40 miles is a light week. You change over time, but the changes don't happen quickly.

The 10% rule is frequently cited; don't increase either your long run or your weekly mileage by more than 10%. I'd like to add that 10% per week, several weeks in a row, may be too much. When I am in base building mode, I tend to increase 10%, leave the mileage steady for 3 weeks, then increase 10% again. But that's just me. You may find you can increase more, or that you need to be more cautious and increase more slowly. It's tough when you're increasing to new personal high distances. It's a bit easier when you're coming back from injury or simply in a training cycle and building up to high distances that you have done before.

If you have to make a mistake, my advice is to make the mistake on the side of not being aggressive enough. There is no bell ringing to tell you that you can run this many miles; there is only pain telling you that you made a mistake and ran too far. The objective is to feel that pain as little as possible.