When I got my heart rate monitor last month, the first thing I wanted to know was what level I should be training at. I used a number of online formulas to work out my Maximum Heart Rate, which turned out to be 185bpm. I knew I was supposed to be working at 70-80% to increase my aerobic fitness, so I aimed for 130-148bpm. This felt uncomfortably slow, but I told myself that I’d get used to it. A chance Twitter comment from Brandon about “zones” got me thinking though. I did some more reading and found out that I really need to be taking my Resting Heart Rate into account. For several days now I’ve been taking my RHR as soon as I wake up in the morning, and it’s averaged out to 65bpm. (Hey, that’s pretty good!) Okay, so 185 minus 65 equals a Working Heart Rate of 120bpm. Multiply THAT by .7-.8 and add back in the RHR, and I get a target aerobic zone of 149-161bpm. That looks better! That should allow me to push a little more without having to walk so much to stay within the zone.

Updated to add: These things are never simple. The great @runjohnerun is not a big fan of this more complicated formula, and he thinks basing it just on my MHR (as I was doing) is better. He’s suggesting I keep my easy days under 145, and my moderate days under 160. That means I’m back to going SLOOOOOW. 🙁