Going out Fast. Or slow.

Shared by a runner who calls this her nemesis. Love her humor.

There was a time I could pretty much take off running right out of the locker room or truck door. My first mile or so would be a bit slower at a given heart rate, but it wasn't anything that really called attention to itself.

For the past year I've noticed a distinct change: my first hundred yards or so are just downright painful, and the first couple of miles I feel like I'm running dressed in armor. Along about mile 2 everything settles in, my breathing becomes easier, my pace picks up at a stable HR.

Along with other changes I see as time goes by, I've quietly filed it away as Well, this is what happens as a runner moves into another decade of life.

I learn from my own experience, but what I learn is always richer and more complex when I stay open to the learnings of others who share. In this week's posting at Sweat Science, Alex Hutchinson reports on a recently published study exploring pacing of workout sessions.

Of particular interest to me was his offhanded reference to oxygen kinetics.

That's where my research curiosity kicked in.

Jonathan Savage, a software-engineer runner with a most informative blog, explains it as the time it takes for oxygen delivery to respond to the demands of exercise. Here's his elegant graphic:

Now that I've got a name for my experience, it's an easy search, vo2 kinetics and age, and quickly any number of links show up. The short version?

Oxygen Update Kinetics of Older Humans are Slowed With Age.

As with every other age-related effect, I can choose to succumb to the reality, or I can work more systematically and with more purpose on my level of conditioning.

And I'll no doubt do some of each, depending on what else is going on in my life or the world.