T Nation

heart rate unreliable?

Hi Guys,

As always I seem to come up with my questions on the cardio equipment. I have been hitting the cross trainer hard for a while and now can do 20 minutes all out. Anyway the display usually says my heart rate is 170 but I don’t feel too out of breath. So I checked it manually and it really is about 165 or so. Fast forward to this weekend. I decided to do some actual running. After 4 minutes I was seriously out of breath but my heart rate was only 124. Whats going on? Is it a lack of breathing technique? (also sorry for the running post at T-MAG but the chances of me posting at “runners world” are slim!)

It’s called “specificity opf training.” Capilarization and blood flow are going to be site specific, so if you aren’t training those specific muscles in that specific manner, then your aerobic reaction is going to be different. Just like cyclists are not going to be as aerobically efficient when running.

While I agree with brider to an extent, my guess is that you miscalculated your heart rate while running. If you really want to figure out what is going on, borrow a HR monitor from a friend and try that on the different exercises.

I agree that you should use a heart rate monitor if your really looking to compare the two. IMO, it doesn’t suprise me that your much more exhausted from the road - a treadmill/xtrainer is always a bit easier in that your not really doing any work to move your body forward - the motor is. So, you go out on the real road, now have this, and perhaps a bit of incline, and your muscles are working in a way they haven’t before, and your pooped. Plus, it’s a different movement (you have to lift your legs and push in a different way then the cross trainer - you probably have to pump your arms, where at most you were just sliding them along).

All very good points. I did use am ironman heart rate monitor to check so the numbers are right. I think the last response was probaly right on since on a crosstrainer I am basically sliding in an arc and running is actually moving up hills and picking up my legs and the like. On a side note I ran again this morning and my body seems to have adapted already as I ran 2 miles in 18 minutes (not too fast but I weigh 210) and was only mildly out of breath, but my calves were hurting!

I have noticed that my heart rate plunges after I stop, and it takes me a second to get my wits enough before I can even keep track of my heart rate, so I found taking it on my own is very unreliable because a few seconds could mean a lot as far as heart rate, At least for me.

The idea to get a heart rate monitor and use it on various exercises is a good idea, but see if you can try it on if it is a chest strap. The one I got barely fits and is very tight at that. If I had the chest size I had a few years ago I wouldn?t be able to get it around my chest. Most are not designed for a large chest measurement.

not surprising really, a X-trainer is basically a non-weight bearing exercise were as running is.
124bpm and out of breath doesnt sound quite right though, did you have a big bowl of beta-blockers for breakfast?