Great article

This might explain yesterday:

It happens to most runners - that dreaded heart rate spike during what was supposed to be a long, slow effort. You’ve reigned in your speed, you’ve kept hydrated and cool, you’ve even switched your running tunes from raucous Van Halen to relaxing Mozart, just to keep that adrenaline rush at bay. But now your heart rate is racing and you’ve strayed outside your recommended heart rate”zones” for your training session.

So what went wrong?

While running can do wonders for the cardiovascular system, it can also cause involved muscle groups to dramatically tighten. And this often includes vital inspiratory and expiratory muscles surrounding the ribcage, as well as the upper back, shoulders, and neck. So while a tight or non-relaxed running posture might result in a trip to your massage therapist for a post-run rubdown, it will also invariably result in short and shallow breathing. To compound the problem, most runners have not been taught how to properly breathe in any activity, including running. In such a scenario, this “tight torso/shallow breathing” causes limited air intake and results in less oxygen availability for working muscles, which means the heart has to pump more of your subpar-oxgyenated blood at a faster rate in order for you to maintain your seemingly relaxed pace.

And Voila - you’re now working at 90-95% of maximum intensity, when your running program tells you to be at 70-75%.

So rather than focuses on deep, diaphragmatic breathing, relaxed head, neck and shoulders, and loose arms, many runners will simply stop and walk. When the heart rate comes back down, they begin running again, and eventually repeat the cycle. This not only ignores the root of the problem, but it turns what was supposed to be a purely aerobic run into an interval session, which trains the aerobic/anaerobic systems to work like a roller coaster. Sure…intervals should be a basic part of any training program, but not a part of a long endurance training session!

What’s the solution to the problem? Endurance athletes, and especially runners, need to intensely focus on breathing and relaxation drills, then apply these drill concepts to their long run.

Link

Thanks Ben for the tips and reminders. This "rings true" and helps me to explain and understand what went wrong. Saturday night, my heart rate was low and comfortable. Sunday it was out of control. I never felt comfortable, I was fighting myself and I paid the price for it. . .