What device do you use to monitor and why should I?

I just got my Polar ft60 with the T31 strap (for swimming) and flowlink. Supposedly this combination work for tracking swimming; although, I haven't tried it yet. I love it so far. I'll report back once I swim with it

I have a Polar FT4, which is the cheapy, basic model. I love it to death, and actually just replaced the battery in it today since it finally died. I can't swim, but it *is* waterproof... and I'm not sure why it would slide or shift or whatever if the strap is tight enough.

I am currently using a Polar Loop (activity monitor) and a Polar H7 HRM chest strap that pairs with the loop. I am impressed with the details it supplies me about my workout. My heart rate, cals burned, % of fat, time spent in certain zones, etc.

I find the heart rate pod itself always slips down when I kick off the wall.

I use my HRM for running, and cycling, but that's more as a training aid than for calorie consumption. The approximations mean that it's no better than anything else for calorie approximation.

I agree. I only use a HRM for running & cycling as well. I use it strictly for training.

I much rather use a formula to calculate calories burned. Too many variants with weather changes to give true calorie burns from a HRM. A heart beating faster doesn't mean more calories burned.

Hmm so this formula calculation is a new concept to me. Tell me more?

So on this website:

http://fitnowtraining.com/2012/01/formula-for-calories-burned/

It has formula for calories burned for men and women. You do use your average heart rate so you would need a heart rate monitor anyways or to check your heart rate a few times throughout your workout and take the average. But it seems like an interesting concept.

I just did a quick comparison and it turns out that my heart rate monitor is off by about 5 calories for today's bike ride. I will continue to use this formula to compare my calories burned though. Nice way to make sure everything is in check

Hmm so this formula calculation is a new concept to me. Tell me more?

HRMs, web based applications like MFP, pedometers like FitBit, Phone apps all use some form of algorithm to estimate a calorie expenditure based on whatever metrics they themselves track.

MFP uses activity and duration, an app will use activity, distance and duration, an HRM will use HR and time, and a pedometer will use number of steps. All of these are subject to some form of error, based on how close the measured metrics are to calorie expenditure, how accurate the reading is and how stable the measured metric is in comparison with the algorithm.

That means that, for example, MFP is quite crude, whereas an HRM will accurately measure heart rate, but if it doesn't know what you're doing then the accuracy can be suspect. For me I'd treat it as reasonably accurate for a two hour run, but not for a 25 minute intervals session. The algorithm assumes that HR stays reasonably stable or has smooth transitions.

A pedometer is going to lose accuracy as you speed up. They're all prone to some kind of error. So it's a question of understanding the type of training and what that error means.

In the case of the type of training that you're talking about an HRM will overestimate the calorie expenditure, a pedometer will be unpredictably inaccurate, Apps won't be picking up a GPS signal so are missing half the information they'd need. That means that you might as well save your money and just use the MFP approximation.

What I meant by saying that I use mine to inform my training, I have a Polar FT60, was that by understanding how my HR is responding to training I can tune my training. If I'm doing a long run I'll keep my HR between 150 and 160, if it goes beyond that for any sustained period I'm unlikely to be able to run for more than a couple of hours. If I'm doing an interval session then I'll aim to get to 190-1195 in the high intensity periods, and down to 150 in the rest periods. That way I know they're going to deliver the effect on VO2Max that I'm after.

It's a question of using the tool for what it's designed for.

If, as above, you just want some extra motivation and the numbers on your wrist will help that, then go for it. You just need to realise that it's not going to be meaningful if you use it for something else, given the type of training that you do.

I use a Polar FT4 for my cardio work (running/combat/spin). It's a useful motivation tool for me. MFP estimates calories burned at around 25% more than the HRM, on average. As some others have suggested: I don't use it as a definitive figure, but as a guide.

I don't swim, so have no idea on whether it could be used for that.