Heart Rate / HRM

beckiboo

How accurate are these? I've got one (York something) and it seems accurate for the heart rate - but I wore it for a run the other day and it said I'd burnt over 620 calories - I ran 15mins, walk 2, run 15, walk 3, run 10, walk 10. Seems like far too many calories for an hour, and I'd only run about 4.5miles.

I wonder if it's got something to do with my heart rate - it's quite low resting (55bpm) but gets up to 160-170 bpm while exercising. Even a 4mph walk on the treadmill results in a 150bpm. When I'm towards the end of my running I'm breathing heavier, but still through my nose (I know I'm working too hard when I start breathing through my mouth!) I probably couldn't hold a conversation, but I don't feel like I'm exercising too hard.

Does having a heart rate that high mean my heart is really unfit? Does having a higher heart rate during exercise mean you burn more calories/is that a good thing?

I've been doing this sort of work out a couple of times a week for the past 10 months or so, so I'm not massively fit but not really unfit either.

Anyone got any ideas?