Intensity

This morning's run on the treadmill felt like I was running though jello on spaghetti legs.  This was the first session where I ran for (all of) three minutes without stopping, but even the shorter sprints were a real effort.

I learned when I first started Nordic Traking with a heart rate monitor years and years ago that my feelings of subjective effort and my actual work only have a loose correlation.  So this morning, I was not running particularly fast - starting at 6 mph - but it felt very very hard to do that. But the heart rate monitor was not climbing especially fast - it was near the end of the second run it got above 145 and maybe got to 150. I started slowing down considerably, all the way to 5 mph, in order to complete the time intervals.  But now, I've looked at the data from my arm band (BodyMedia Fit) and by its calculations, I was in fact working harder than on any of my previous runs.  This device counts effort as "mets" which I've never really figured out. I just consider it some number that shows relative effort.

According to my armband, I have to work above 5.5 mets for it to be vigorous exercise. Above 3 mets is moderate exercise.  Many days, including days I go to the gym, there is no vigorous exercise at all.  But running definitely gets me there.

The armband has sensors it uses to calculate mets. It has 3-axis accelerometers to know how I'm moving, and then it is in contact with my skin and it measures temperature and connectivity - which is a measure of how much I am sweating. It does some complex math to figure this stuff out and convert it to activity. The smarts of how it does the calculations all lives on the internet, not in the device itself. The raw data has to be uploaded to the companies servers to get the results. I do the upload generally only once a day, using my phone to send the data.

All of my runs this year have hovered around 8 mets of effort. When I'm doing intervals, it shoots up during the runs but doesn't drop all the way down during the rest walks.  Today, the effort shot up over 10 mets for most of the time after I started running. So my subjective feeling of working harder was truly based on how my body was acting, at least in terms of heating up and sweating. The heart rate lagged that feeling of hard work, but there is at least some validation to how I'm feeling.

So what do I do with this information?  I think it means I slow down. I keep going, running versus walking for the full time, but slower if necessary.  Oddly enough, as little as I'm doing, it seems to be resulting in "over training".  I'll keep plugging along, and even pushing myself, but not harder than seems productive.