Here's my take on it, broken into two key points:
1. If you think running really high mileage is good for your health, you're probably a delusional idiot. People run high mileage for lots of reasons, but if you're doing it for health alone, there is no reason to run 50 miles a week.
At no point in an ultra marathon does any runner think "Hey, my body LOVES this. I am the smartest person alive!" Many high mileage runners may enjoy some health benefits like a lower resting heart rate and faster metabolism, but that's not their main motivation in running so far. Personally, I like the challenge of the longer distances and I really enjoy a quiet, peaceful race experience so trail races are my favorite. Starting out on a long run in the woods feels like the start of an adventure.
|This is how I picture myself|
2. You're going to die one day.
Abstaining from activities that you enjoy just in case it might shorten your life is stupid. It's not like smoking where you KNOW it's going to end your life sooner. There are so many factors that go into running deaths (family history, diet, lifestyle, etc) that it's impossible to say that "Yes, running killed them".
There is nothing wrong with wrong 14 miles a week...unless you want to perform at a higher level or run distances longer than a 10K. The new guidelines also say that running faster than a 7:30 pace or slower than a 12:30 pace really increases your hazard level, but maybe that's because fast skinny people don't eat enough to be healthy and slow fatties have complications from their extra body weight. See how it isn't as simple as just how far or fast you run?
|Also in the study: going slowly down slides is unhealthy|
I've never been a really high mileage runner because there is a limit to how many miles I can squeeze in with young kids, but I would never limit myself to a certain weekly mileage because some study suggested it may be healthier. If I had the chance right now, I would run a higher weekly mileage like I was pre-pregnancy because I feel like I perform my best when I run 50-60 miles a week. In ten years there could be a new study that shows that running excessively actually makes you really attractive and smart. In my case study of one, so far that is true.
Here's an example: When I was a baby, all the doctors said to put babies to sleep on their stomachs or else their chances of dying in their sleep would increase. Now they tell you to put your babies to sleep on their backs and stomach sleeping is for horrible parents who don't love their babies. Numerous studies supported both theories...so obviously you have use your own judgment at some point.
If a scientific study suggested that some activity that you enjoy was unhealthy, would you stop?