Years ago a good friend who was in fairly good shape had a heart attack and died while out riding. This kind of was a wakeup call for myself, so I got a Heart monitor (HM) I found it interesting as I am a bit of a guage weenie anyways.

However one day I was back home visiting mother when I decided to go for a run. It was very hot (thirties centigrade) and I was in my usual big rush. I was going up a steep hill full blast when I noticed what I thought was gas pains. It sort of struck me as odd to have gas pains and then I noticed that my HM was showing 169. A bit of quick math (I was 51 at the time) 51 plus 169 = 220. It suddenly dawned on me this was some sort of heart problem. Yikes! I immediately pulled over and stopped under a tree and waited for the rate to get down to a sensible amount. Then I walked the bike up the hill and had some water. I felt no further pain or problems so I let it go and subsequent EKGs showed no issues.

I consider my monitor to be my friend and I use it to be a heads up to back off on the throttle. Another method I found from a doctor Mike Douillard a triathelete, who essentially said that when you feel your heartbeat starting to creep up your neck to your throat, back off or stop because when you are using up this much energy, you are wasting it and at a certain point you are being very dangerous to your short and long term health. I use this advice and it serves me well. It keeps me from feeling tired after a ride or exercise.

I know there is a whole science to using a HM for training and I used to use around 140 as a max 130 as a minimum but I haven't really learned enough about it to completely understand, but I highly recommend getting a monitor if you are a Type "A" like me and don't know when to back off the gas.

I may be completely out in left field, but my understanding is that if you're in reasonable shape, you won't hurt anything by running your heart rate up to its max. In fact, if you don't know your max HR, how can you know the zones that are applicable to you?

That 220- your age thing is just a ballpark number anyway... not an absolute.

I know for me, I've seen max numbers in the mid-180s on my HRM and just today saw in the low 170s for a stretch. Often I'll cruise in the 160s for a good while. Point is, everyone has individual max HR numbers. It's not a cookie cutter type thing... or so I understand.

As always, consult your doc before beginning exercise. And if pain begins, backoff like you did. Seems the smart thing to do.

Hey, I'm certainly no expert. Didn't even stay at a Holiday Inn Express last night. But unless I've misunderstood what I've read here and about, I believe the above info is valid and I have been riding based on it. Hope I don't blow a headgasket or something. ;)

I'll turn 58 later this year. Here's an example of a short ride I did this morning:
http://img175.imageshack.us/img175/3029/gtcexamplehg7.th.jpg (http://img175.imageshack.us/my.php?image=gtcexamplehg7.jpg)

Heart rate monitors are not medical devices and tell you nothing more than your current heart rate. They are not a substitute for an EKG and would be ineffective at detecting an impending heart attack. You don't need a heart rate monitor to know if your heart is racing. Pounding up a hill in hot weather is a sure way to get your heart rate up near it's maximum and, so long as you don't have any pre-existing heart condition, should be safe to do. That is, unless you faint from the exertion and fall off the bike.

There are lots of variables as have already been mentioned. Another one that could have easily impacted you on that HOT ride your were doing is something called "heart rate drift". When it starts to warm up outside this too will have an impact on your HR. In hot conditions your heart is pushing not just he normal amount of blood to supply your muscles but also moisture for you to perspire. As a result your HR will "drift" as compared to the same workout on a cooler day.

This is not to debunk the value of an HR monitor but just the fact that you need to know what it is telling you and to know your body (what is your true max HR).

After I got my HRM, I used to be worried because it just didn't feel like I was doing much work unless I pushed my heart rate well beyond the "acceptable" rate for my age (57) and I was worried I would "hurt" myself. I had a talk with my doctor at the U.W. sports medicine clinic about this and she said your own sense of how hard you are working is a more reliable indicator and the only way to truly determine your max HR is with a treadmill stress test.

It also turns out the 220-age formula is extremely inaccurate (http://www.heartzones.com/healthpros/resourcezone/articles/max/220-agerobergs.pdf) and is worse than useless (http://www.heartzones.com/healthpros/resourcezone/articles/documents/CarlFosterHRMax.pdf)

I highly recommend Sally Edwards Heart Zone (http://www.heartzones.com/resources/) web site to anyone interested in using heart rate as a training tool and an HRM is just a tool. It's how you use it that's important.

I should explain myself a bit. I am not interested in training for anything. I ride my bike periodically for transportation. Aside from a period of time in my teens when I ran two to ten miles a day for a few years and in my mid twenties when I swam 2.5 Km per day for a couple of years and a few years when I did the RCAF 5BX program (at the champion athlete level) I basically just ride to the corner store and across town periodically. I once on a whim drove 150 miles with my daughter with about 1 hour of preparation and zero forethought. Wonderful experience. Essentially I use my HRM as a guage to warn me about getting carried away with exercise.
My friend on the other hand uses no HRM yet he runs, walks snowshoes mountain climbs, chops wood for hours. He paces himself naturally, whereas I am all out or nothing. I know what my habits are and I know that I can hurt myself. If you discover a problem, via the EKG you may be able to do something about it then instead of waiting for the time bomb to go off.
I am a pilot and if I have a problem with my EKG which I am legally obliged to have annually, I am unemployed not to mention potentially dead or damaged.
My wife's normal heart rate is lower than mine because she ran 6 Km daily for 15 years.
Having said all this I appreciate all the info. I have always known that using a HRM is more than just a a simple little formula but was too lazy to get right into it and read the books. Thanks for the links. I read some of the info and will read more as time goes on.
There is a lot that goes into all of this "science". These modern theories tend to be a moving target and so to me they are unreliable.
I am fascinated by an old medical system from India called Ayurveda. Been studying it for years. In Ayurveda people are classified according to their body type. For instance a Kapha (predominant) body type needs heavy exercise regularly and should push themselves. A Pitta (Predominant) person is more for medium exercise and heat is a bad news for them. A Vata (predominant) person should do light exercise and things like Yoga asana or Tae Chi. To me this makes more sense than stress tests and checking blood oxygen levels. However to each his own.
If a Vata type person trys to become a champion athlete they may succeed till they hurt them self so badly they end up in irons the rest of their life. If I trained for the Boston Marathon I would probably end up in the Massachusetts General... : )

HRM's are great tools but you need to understand a few things:
1. You need to test your max HR or else it tells you next to nothing
2. It's always a few seconds behind your actual heart beats
3. The BEST heart rate monitor (Polar as tested by Consumer Reports) is only accurate to within +/-5 bpm. That means if it says your heart's beating at 170, it could really be 165 or 175 or anywhere in between. And that was the most accurate HRM they tested.
4. HRM's are also succeptible to magnetic interference. So if it suddenly reads 230, don't panic, it's likely electro-magnetic static.

4. HRM's are also susceptible to magnetic interference. So if it suddenly reads 230, don't panic, it's likely electro-magnetic static.

And, if the monitor slowly descents to zero, don't worry. Thought I was dying one time as my heart rate started dropping lower and lower, finally reaching zero - just a bit of interference that I always seem to get at the same spot. Scary the first time though :).

I spoke to my doctor about my heart rate. I am 53 and do a lot of hiking and backpacking in some very rugged terrain. I mentioned that I set my upper limit on my monitor so it beeps at 165 and often have periods where my rate in in the mid-170's during some of the more difficult climbs. I asked him is this was too much for my age. His response was that as long as I am not having problems breathing (shortness of breath) and am not feeling any heart related pain or becoming dizzy, all is well. I had an EKG this year and all checks out, so I really don't worry about my heart rate anymore.

I am using a Suunto T-6 with a bike pod which gives me speed and distance along with heart rate and altitude - works nice so far.