Thursday, August 28, 2014

Very High Max Heart Rate


Interested in what can be learned, if anything from monitoring my HR during runs.

I am 61 years old, 73.5kg 179cm / 162lbs 5' 10.5", running about two 5k sessions a week for the last year until a tennis injury knocked me off my feet (torn gastrocnemius and 2 fractures on front of shin).

My resting heart rate is between 50 and 59 depending on how much sleep and stress level.  For the last 10 years I have been using 188 as my max HR based on a conconi treadmill test estimation.

Before the injury my maximum exercise HR was usually between 170 to 178:

 Before Injury: Max exercise HR of 170 during weekly 5k run

Today I started running again again (1k walk, 1k run, 2k walk, 1k run, 0.5k cool down walk) and noticed that my HR was up higher than previously seen.  It was a bit hotter today at 95 deg. F, but I drank continuously and felt very good during and after the run.


Two and half months later:  Maximum exercise HR of 183 and 186 during 1k intervals

I was thinking that I was running my 5k at around 90% of my maxHR, but today's run would seem to indicate that my MaxHR is actually much higher for me to be able to run at 186 for these intervals.

Anything else I can learn from these data?

The Fitness Test Result Nearly Killed Me

(repub - original site went under.)


(VO2 max estimation method comparison)

Alan McDonley, Jan. 2007



In 2006, as part of an employer sponsored fitness assessment, I chose to take a 1.5 Mile Aerobic Fitness Test. The test was described as "run or walk for 1.5 miles and time yourself. The objective is to cover the distance in the shortest time possible." When I entered my resulting time into the website calculator, I received a surprisingly poor result. After more research, I concluded the website calculator was not appropriate to the test and found validation in the fitness assessment method I had been using for the prior seven months.

Also at that time, a "negative" (no excessive risk) Bruce Protocol stress test reported I had a "mild to moderately reduced exercise tolerance". My time was 6 minutes 16 seconds, which correlates to a VO2max of 21 by the estimator:

VO2 max=14.8 - (1.379 × T) + (0.451 × T*T) - (0.012 × T*T*T)

That was an indication of "very poor" fitness for my age, and I resolved to begin exercising three times a week at a local community center.

(Note: It also seems likely that my higher than norm max heart rate caused the cardiologist to terminate the test early when I achieved 100% of the age calculated max heart rate.)

Since I had not been exercising much and was then 53 years old, I decided I should purchase a heart monitor to make sure I did not exceed the guidelines for my age. I chose to purchase a Polar F11 watch primarily because it also contained a "fitness test" function.

The F11 fitness test measures heart rate variability during a five-minute undisturbed rest lying on the floor and reports an estimate of VO2max. Before beginning my exercise program the watch estimated my VO2max at 27, which correlated to "poor". That assessment was higher than the Bruce Protocol test result, but still strong motivation for me to start exercising.

I continued to perform the F11 fitness test periodically. After the first two weeks my VO2max moved up slightly to 31. The test results remained quite constant until beginning a slow climb in the third month of exercise. By the middle of the fourth month I had entered the "good" range with a test value of 37 and the slope was looking good. At six months I was coasting along the bottom of the "very good" with a value of 42.



In the seventh and eighth months, I didn't work hard enough, skipping two whole weeks, twice in fact, and my F11 test score dropped back into the "good" range with values around 40.

When my employer again enticed me (with $150) to do a run/walk treadmill fitness test, I was excited to see if the result would correlate with my Polar F11 test results. I warmed up for a tenth of a mile at 2 mph, and then started the stopwatch and distance count. I ran at 6 mph for a short while till my heart rate was pushing 95% then backed off the speed to 4.2 mph to hold a steady 90% (150 bpm) till the 1.5 mile mark at 21 minutes even.

I rushed home to plug in my result and when I did, whoa baby, there's a problem here. The fitness assessment website calculated the VO2max for my 21 minute run/walk as 26.5 and labeled my fitness as *poor*. It appeared that the website was using a "maximal effort" VO2max estimator developed by KH Cooper. There are many Cooper tests, and several sites list the 1.5-mile Cooper estimator as:

VO2max = 3.5 + 483 / (time in minutes)

That was quite a shock. The next morning I tested myself with the Polar F11. The test estimated a VO2max value of 42, which is the bottom of the "very good" for my age.

Thanks to the Internet I was able to discover two more ways to interpret my treadmill test that correlate extremely well with my Polar F11. The first was a study by Brigham Young University of telling subjects to run, walk, or jog "somewhat hard, at a steady pace" for 1.5 miles. By having the subjects also perform a standardized maximal graded exercise test they developed estimators for the 1.5-mile sub-maximal of:

VO2 max = 65.404 + 7.707 x gender (1 = male; 0 =female) - 0.159 x body mass (kg) - 0.843 x elapsed exercise time (min; walking, jogging or running).

VO2 max = 100.162 +/- 7.301 x gender (1 = male; 0 =female) - 0.164 x body mass (kg) - 1.273 x elapsed exercise time -0.156 x exercise heart rate

Using the first estimator, my 1.5-mile test would indicate a VO2max of 42, exactly the value of my Polar F11 test.

Using the second formula, (with a +7.301 male coefficient), gives a value of 43. (The formula is taken from the abstract citation which had a plus/minus in front of the gender coefficient. Using the minus coefficient yielded values which did not agree with their non-heart-rate estimator, while the plus coefficient did.)

Next I found the Rockport Walking Fitness Test. This is a 1-mile sub-maximal walking test with instructions "Walk 1 mile as fast as possible". The estimator for this test is:

VO2max = 132.853 - (0.0769 × Weight in lbs.) - (0.3877 × Age) + (6.315 × Gender: 1=male, 0=female) - (3.2649 × Time) - (0.1565 × Heart rate)

Since I "walked" at a steady 4.2mph at 150 bpm for most of my 1.5-mile test, I can use 14 minutes (21min * 1/1.5), which results in a VO2max estimation of 43, again close to the Polar F11 heart-rate variability test value.

As a result of the "shock" and the further research, I had increased confidence in the Polar F11 VO2max estimation and felt that I could use the watch to measure the results of my exercise program. I felt "very good" about my exercise program results, although I didn't actually believe that I had achieved "very good" fitness!



Update: June 2007 - I've been doing the C25k (couch to 5k in 9 weeks) running program for the last five months now. I've discovered by doing a running Conconi test that my HRmax is 20 bpm higher than age predicted, so that I can allow my heart rate to go over 150. I still am no where near the "average" but I am now able to continue with the program. I am able to run 8 minutes at a 17:00 mile pace (3.5mph) and my heart rate levels off around 160.

Update: Aug 2014 - I started the C25K again a year ago, and have been running one or two 36-36 minute 5k sessions each week with an average heart rate around 173 and a max exercise heart rate of 178.  I'm still slow (47% age graded) but I am enjoying my runs.  Interestingly I have run some 1k segments at 186 bpm and felt great during and after, so I'm now thinking my max heart rate might be more than the 188 I have been using for zone calcs.


© Alan McDonley 2007 All rights reserved.


References:
a)     Bruce Protocol VO2max estimator:
http://www.brianmac.demon.co.uk/bruce.htm

b)     Cooper 1.5-mile VO2max estimators:
http://www.exrx.net/Calculators/OneAndHalf.html

d)     Rockport Walking Fitness Test VO2max estimator:
http://www.brianmac.demon.co.uk/rockport.htm

e)    Polar F11 Heart Rate Variability:
http://www.heartratemonitor.co.uk/research.html