There are many different ways to calculate your ideal workout heart rate, we'll call this your target heart rate(THR). As I understand it, if you workout at too high a heart rate , your workout ends up being counter productive. Now as far as I could see, this is somewhat of a non-precise science.
For your THR you need to know your maximum heart rate (MHR) and your resting heart rate (RHR). An empirically derived formula provides you with your THR.
To know your MHR is part of the problem. You need to push yourself while under the guidance of a medical practitioner and be connected to an EKG. Where your heart starts showing signs of stress is where your MHR is established. This might be a little dangerous to approach on a regular basis, especially if you are a little older. So "they" came up with a little formula for your MHR.
MHR = 220-your age
Your RHR is easy to measure, but to get it completely figured out might require you to measure it regularly.
So then you use the formula of your choosing (and I say this, because there are several, but I found the product of all to be within a close range) to calculate your ideal THR and purchase a heart rate monitoring watch. On it you set your THR and an alarm goes off every time you cross the THR barrier. This was an easy enough formula and probably the most popular one.
THR=((MHR-RHR)x0.85)+RHR
Having said all this. I calculated my THR using all of these formulas and it was suggested that I run at 161 beats per minute (bpm), but while running I found myself being very comfortable at 170-172 bpm. So on the last half a mile I turn it up a little and watched my heart rate climb. I was amazed at the difference between 185 bpm and 188 bpm. I had to stop the run and walk for a few seconds to regain my breath before I could run the last 100 yards to the end. At 185 I was tiring, but the moment I reached 188 there was a clear lack of oxygen. The change let me to believe that I was reaching a current MHR, but I plan to verify my personal findings tomorrow by running hard sooner to see if there is greater heights to be reached with my MHR.
I plan on running without Esme' (my 22 month old daughter) so that she would be safe if I push a little far. I personally believe that I could approach 200 bpm without consequences.
So when I returned, I reverse-calculated my MHR by using the 172 bpm as my THR. Now this is not science and I know it, but it seems to me that if I felt like I could run forever at 170-172 then that is a good gage of what my true THR should look like. Since my RHR is 50 bpm I was able to calculate my MHR at 193 bpm. Now this presses the next self indulgence in me. There is a difference between the heart of a fit person and that of one that doesn't ever take his heart out for a run. So I went and reverse calculated my heart age by subtracting my MHR from the suggested 220 bpm and so I was happy to report on a 27 year old heart in a 39 year old man (I believe I don't look it, but...).
A few more gleaned facts: Small people have higher heart rates, energy drinks increase heart rates, the more fit you are, the lower your RHR and perhaps your THR (I'm not sure about this, because it seems that the mussle called your heart could run faster with exercise) and I will be liable only for my own actions and you remember to read more reliable data on these issues. I am not a doctor, nor do I have any more knowledge on the subject than what I found on the web. I wouldn't sue them and I wouldn't pay you if you went and stressed your heart out.;)
Joining me on this challenge happens entirely at your own risk, but to not sound scary, real long distance runners run at least 1500 miles in one year and that challenge we leave for next year. God willing we will all still be around.
The article I read, said that the 5 times Tour De France champion endurance cyclist, Miguel Indurain, was the person with the lowest RHR ever measured and it was at 28 bpm. Less than one beat for every 2 seconds. Imagine you were an EMT at an accident site where Miguel might have fallen and you were in too much of a rush, because there was several cyclists down, you'd perhaps declare him dead.
Perhaps the two most significant bites of information is:
1) Heart rate recovery: The heart rate measured at a fixed (or reference) period after ceasing activity; typically measured over a 1 minute period.
Heart-Rate Recovery Immediately after Exercise is a Predictor of Mortality.
For death, it has been hypothesized that a delayed fall in the heart rate after exercise might be an important prognostic marker.
Study by: Christopher R. Cole, M.D., Eugene H. Blackstone, M.D., Fredric J. Pashkow, M.D., Claire E. Snader, M.A., and Michael S. Lauer, M.D. ; Art. ref. from the NEJM, Volume 341:1351-1357 October 28, 1999 Number 18
2) Higher RHRs are dangerous: An Australian led international study of patients with cardiovascular disease has shown that heart beat rate plays a key role in the risk of heart attack. The study, published in The Lancet (Sept 2008) studied 11,000 people, across 33 countries, who were being treated for heart problems. Those patients whose heart rate was above 70 beats per minute had significantly higher incidence of heart attacks, hospital admissions and the need for surgery. University of Sydney professor of cardiology Ben Freedman from Sydney's Concord hospital, said "If you have a high heart rate there was an increase in heart attack, the increase was about a 46 percent in hospitalizations for non-fatal or fatal heart attack."