Search This Blog

Thursday, February 11, 2010

RPE vs. Target Heart Rate

An old friend of mine from high school (the second of the three I attended) who read my last blog entry, Crunch the Numbers, had a great question, and it's one I want to hit on today.  She wrote to me:

"Since we're the same age, my target HR should be 161 too, but I'm almost always up in the 180's when I'm on the elliptical, and God help me when I'm running! The thing is though, I can sustain that for an hour no problem (well, not so much the running, but the 180's), and if I drop down to 160, I feel like I'm not pushing myself hard enough. So what's the deal with that?"

This was such an excellent question, and one I'm sure quite a few of you are asking yourselves, if you started using my Heart Rate formulas.  Many of you will find that, if you really push yourselves, you are blasting way past your THR.  So should you slow down?  What if you are in good health (as my friend Carly is) and are still not really pushing yourself at your THR?  What does that mean?

First let me start off by saying, You're All Unique.  These numbers are AVERAGES, and that is important to remember.  A  HR of 162 may kill one 31-year-old and barely challenge another.  This is in part due to your resting heart rate.  If you are out of shape, your resting heart rate will be much higher, and therefore when you work out, your heart rate will climb much higher than a person who is very cardiovascularly fit.  When you are in good cardiovascular shape, your resting heart rate can tend to be much lower, resulting in a much lower active heart rate, comparatively speaking.  There are yet more things that could affect your heart rate, individually, that are genetic and/or environmental.  These may include, but are not limited to:

hypertension
hypotension
high cholesterol
use of stimulants (caffeine, ephedra, certain cold and asthma medications, etc.)
use of depressants (alcohol, marijuana, muscle relaxers, sleeping pills, etc.)
certain health conditions (heart conditions, lung conditions, etc.)

So you see, the THR formula is not going to work for everyone, because you are all so unique!  Now, I'm sure you're wondering why the hell I even bothered giving you the formula in the first place!  And the reason is this:

While your THR may be much higher than the one listed by the formula, it will NOT be LOWER than the one listed.  So you must consider this your lower limit for maximum caloric burn.  It is still an important number.  But for those of you who can't count to save your lives or whose THR does not match your experience on the treadmill, there is another method.  It's less specific than the THR model, and I hate using it because people use it to cheat too much.  It's called the BORG scale, or RPE scale, for Rate of Perceived Exertion.

The Borg scale was created in 1998 by doctors looking for a way to estimate a person's exertion level using their physical experience of the exercise.  It's on a scale of 6 to 20 (although there are modified scales that use the 0-10 rating for greater ease), and you can read all about the scale and how to figure your exertion level using it here:  http://www.cdc.gov/physicalactivity/everyone/measuring/exertion.html

This is where I caution you.  Guys, don't do yourselves a disservice and use this scale to try to convince yourself that you're working out harder than you are.  If my formula said you need to work out around 162bpm, and your normal hardcore workout is 180bpm, don't check the RPE scale and say, "Oh, well, really, 162bpm is still a level 12-14 intensity so that's good enough" and scale your workouts back!  If you know 180bpm is where it's at, for pushing yourself, then DO THAT!  Don't get lazy!  If you've been shooting for HIIT training and your heart rate hits 187 at the peaks (that's what mine did when I first started working out last March), don't use this RPE scale to tell yourself that it's ok to take it easier.  It's NOT ok to take it easier.  Here are the benchmarks you should notice when you're working out at your ideal exertion level:

You shouldn't be able
to get out more
than this many words
without taking a few
deep breaths in between

Get me?  You should only be able to speak 3-5 words and then need to breathe!  You should NOT be able to carry on a conversation of more than the length I gave you just now.  Talking during a good workout should take you from that threshold of being somewhat out of breath and breathing quite heavily, to making you have to gasp and start to see black spots if you keep talking.  You should need to CONCENTRATE because you're going so fast, you should need to be focused on maintaining your exertion level, and you should be SWEATING IT.  Now, some of us sweat more than others, and we're more likely to sweat when it's hotter, or when it's more humid, or when we've had more to drink.  In a 65 degree room in low humidity, in 20 minutes you should at least have soaked the neckline of a cotton t-shirt a bit.  Your neck, chest, face and hair at the scalp should be very damp and you should be dripping a little bit.  And you should need a few minutes to stop, hold your arms over your head, and catch your breath when you get off that machine.

Now, you need to know that, as you get fitter, your resting and active heart rate will get lower.  Great, right?  Your heart is in better shape!  Here's the downside.  That means you have to work your body HARDER to hit your THR.  Your body has gotten good at doing the work, so it's not challenged as much by it any more.  20 minutes of HIIT intervals on the elliptical at a level 7 may not cut it any more!  You may need to up it now to a level 8.  Then to a level 9.  You may have to increase your speed as well as the resistance.  You are going to have to WORK for it!  Skinny, fit people do not have it any easier than heavyset people do.  On the contrary, the more efficient your body is, the harder it is for you to challenge it enough to lose weight.  So keep that in mind; as you get more fit, your workouts MUST get harder to maintain that challenge!  If the workout is getting easier, take it up a notch!  Change=Challenge, people, a concept I'll be touching on in my next blog.  In the meantime, get out there and hit those ellipticals/treadmills/weights!  Don't Think, folks, Just Go!

No comments:

Post a Comment

Watch Me


Words to Live By