Do you use a heart rate monitor?

I use an HRM for my Zumba classes - it's the only way to get an accurate reading of how many calories I've burned.

I don't. Recently got a fitbit and have been wondering if I would get any extra benefit from a HRM though...

The FitBit is only good for some activities. It's incredible inaccurate compared to an HRM. For example, a FitBit wont recognize the burn when you're biking.... or on a treadmill but holding onto the bars. The FitBit is great for just your average daily activities, but not so much for your exercising.

I have the Polar FT4 and LOVE IT!

For the love of everything holy, NO.

I returned mine few weeks ago. I lost most of my weight without one, and using one just slowed me down. I understood it gave me accurate results, but I don't need to focus on anymore numbers or depend on them.

Yes I do. Have had one for over two years (Polar FT40) and I can't imagine working out without it. The only time it ever gave me problems was when the battery was dying, so I just switched it myself (which was easy on this model) and now it's working perfectly again.

You want to get one with a chest strap, and you want to rinse it off after each time you use it. I've never put my strap in the washer, but I rinse it well right after each time I use it, and that seems to work fine.

My HRM not only tells me how many calories I burn, but also tells me my average heart rate % throughout my workout, as well as my highest. (I have it set to show % and not the actual HR, you can choose which to show of course). It also tells me how long I was in fitness more, and how long I was in fat burn mode. And it has a fitness test I do about every few month (or, you know, should do every few months, he he) that is what it bases my calorie readings/max HR settings on. Some Polar models may not have this, but the FT40 does.

So, a very long answer there. But honestly, it's worth the money to get a good model. A lot of people here have the FT4 or FT7, I swear by the FT40, and know the FT60 is pretty awesome too. A bit more expensive, but worth it. I use it to know how hard I am pushing, and how much harder I can push. Without it I feel a little lost to be honest, and I hate not knowing just how much I burn each time I work out!

For the love of everything holy, NO.

I returned mine few weeks ago. I lost most of my weight without one, and using one just slowed me down. I understood it gave me accurate results, but I don't need to focus on anymore numbers or depend on them.

Ding Ding Ding! That's it right there.

This HRM hype has turned exercise upside down. Exercise is pure. An activity you do to change yourself for the better. It's not about this mythical "burn". Lift heavy things to change your both your bodies capabilities and it's shape. Do cardio to improve your endurance. The number that MFP or your HRM spits out about your calories burned has no significance. Get stronger/faster/better while eating sensibly and you will succeed.

But I see thread after thread on here where people bicker about a 100 calorie difference in an exercise log. Or where they ask which activity has the highest burn rate? WHO CARES? Pick the activity you like, and get better at it. You can run 2 miles? Good, now try to run 3 miles? And then try to run it in a faster time. You can bench 185? Good, now put 2 plates on the bar. Now gimme 5 more reps. If you go about your business like this, I promise you that you start liking what you see in the mirror.

Whether you burned 350 cal, or 425, or 1000 won't make a whit of difference. Instead of going after a monster 800 calorie burn, get a 300 cal burn at something you enjoy and don't put cream or sugar in your coffee. Same difference.

I use one and it gives me an accurate reading of my calories burned. Also it helps me from overdoing it by showing me when I am getting out of my safe zone in heart rate.

I use a Polar ft4 HRM. It's about $65 on heartratemonitor.com free shipping. It has a chest strap for accuracy and is basic - just heart rate and calories burned. Relatively easy to use. I love mine.

I have a Polar FT7 and I love it. I'm a former accountant (now a SAHM), and I like numbers. The more numbers and data you can throw at me about my health and progress, the happier I am. I am motivated by numbers - it's just the way my brain works.

It's helping me learn more about my fitness level and workouts. Eventually, I suspect I will stop using it - but for now, while I'm still learning a lot of this stuff, I find it very useful.

What makes everyone think they are accurate?

They measure heart rate, not calories burned. The calories burned is a guess, just like MFP or anything else.

No. Nor do I attempt to calculate cals burned with exercise at all.