Training & Nutrition - Beyond my max HR?

I've just gotten a new Polar S150 HR monitor to replace an old Cardiosport and it tracks my max & average HR for my workout. My max HR should be 174 (I'm 46), I'm in good shape, been cycling for years, drink little and quit smoking 27 years ago. Day before yesterday while doing the Spynergy Uphill Grind DVD I hit a max of 173 and could believe that as hard as I was working. But today while mountain biking I hit a max of 184! Is this possible? If not what could be causing the readings? I didn't feel like I was working harder mountain biking than when I was on the trainer. The trail has short climbs, though a couple of them are steep and it was cool (low 60s).

Thanks, Bob

My max HR should be 174 (I'm 46), [...]
Sounds like you're going by the 220-age formula to determine your max -- this is a very general formula and isn't correct for every individual. The best way to get you max HR is to have yourself clinically tested. There are also ways you can derive your max HR by determining your lactate threshold using road trials. Either way, I'm fairly sure your max is higher than 174.

Like Grendel said it sounds like you are using the 220 minus age theory to calculate your max HR. This is just a guide for the general population, and will vary a lot in fit people. Clearly your max HR it is at least 184bpm. I am 34, so in theory my max HR is 186, however it hits 200 often in races, sometimes up to 203. Don't be concerned.

CHEERS.

Mark

Thank you both. I guess the good news is I'm not going to explode. The bad news is if my Max HR is that much higher than I thought then I've been training below where I should be when I use my HRM to train.

Later, Bob

the 220-age theory was literally written on the back of a cocktail napkin on an airplane by a doctor and his asst while going to a conference as a quick approximation. it is not an accurate measure. many people have a genetically predisposed max HR that can't be approximated with such a simple formula.