(Cross posts with harrumph). HR
max misconceptions are a pet-peeve for me.
I have mixed feelings regarding HRMs. They certainly tell you when your not trying, but as you get older and begin to feel less invinciple, they frighten you to death.
The highest maximum HR (using the most opimistic formulae I can find) for may age (64) is 170 BPM. During a "10" my HR will be around 160 - 165 peaking at 175BPM, I have to fight the temptation to throttle back at 170BPM for fear of blowing the engine.
The formulae are there to estimate your HR
max in the absence of proper data. Your HR
max is not some magical limit that if you go over you'll die, it's simply the maximum HR
you personally can achieve.
If you have no other data to draw from then use a formula (pick one, any one) and use that figure. If you see a higher figure on your HRM then start using that. If you want a more accurate HR
max test then there are plenty to find with google, you just have to get off the bike and do a bit of running (ideally on a treadmill) and get ready to visit the vomitorium.
I can get at least 15bpm over what most formulae suggest for my age. I'm 31 and I've seen 206bpm playing 5-a-side football, but I can only get it up to about 195bpm whilst cycling. It doesn't concern me at all as I'm perfectly healthy, and I've discussed this with doctors who showed no concern whatsoever.
The only thing to remember is that HR
max does trend down at about 1bpm (although it will vary between individuals) so it's best to re-evaluate your HR
max each year.