In reply to michael lawrence:
> (In reply to lost1977) thanks. Are you suggesting that more running sessions per week will bring down my average heart rate for my longer runs? The question isn't "should I do more running sessions" as I know the answer is "yes". The question is "do I follow the 75% MHR rule or not"?
I think you've misinterpreted the rule.
Your max heart rate is supposed to be 220 - your age. So at 41 it's 179 and 75% of that is 134..
I think it's bollox as is the holding a conversation advice.
I suggest you go for a run of a reasonable length at a pace you can keep up for a good few miles without thinking you're going to die. Don't look at your HRM until you get home and can look at the data on your PC. The heart rate you had is about the heart rate you should be training at for the longer runs. For me that's about 165 but I'm 54 so I suspect it'll be a bit more for you.
When you do the race don't look at heart rate at all, by then you'll have a target speed you'll want to hit and just try and hit that (I'm assuming you've got a GPS watch thing).