 Becoming
a Better Animal: How to Effectively Use Your Heart Rate Monitor.
Part
1
of 2
by
Scott Herrick
So you’ve just finished running 40 blissful minutes. Still dripping sweat,
you slog through the house towards the den while removing your brand new
heart rate monitor chest strap. After downloading the workout data to your
PC, you find out that you averaged 155 beats a minute. You then print out
a pretty 4-color graph capturing each beat of your trail escapade to hang
proudly on the fridge, edging out space from your first-grade daughter’s
64-color masterpieces. Your new toy has performed flawlessly, you now know
what your heart did minute by minute, and your spouse has visual proof
that it does indeed do everything the brochure said, thus justifying your
lobbying efforts. Now what?
Hopefully your heart rate monitor purchase was intended for improving your
athletic performance and not solely to compete with a five year old’s
Louvre ambitions. In a 2-part series, I’ll cover how to use a heart rate
monitor to help you train and race more effectively, what information it
can’t tell you, and some common myths about heart rate-based training.
Here in Part I, I'll explain how to determine training zones with a heart
rate monitor and show how using the monitor is unique to your own
physiology and sports you compete in. After we setup training zones, Part
II will explain how to put this information to use in training and racing,
and also explain some pitfalls and cautions in using the monitor.
To use the monitor effectively, you need to know how hard your heart is
working relative to your body’s capacity for the activity you are doing.
Some training days are going to be easy, others will be harder efforts,
and the monitor can help you stay within range of effort for a particular
workout.
The single best outcome from using your heart rate monitor is to ensure
your easy days are easy and your hard days are hard. This sounds
almost too simplistic to even mention, but habits dominate almost every
aspect of our lives, including being an athlete. “Just going out for a
ride” tends to result, by sheer habit, in cycling at nearly the same
effort whether it’s 60 minutes or 4 hours. Your body improves most by
cycles of stress and recovery, and using your monitor correctly will help
keep each workout on target, whether it is lung-busting intervals, or an
easy recovery ride.
So how do you know if you’re working at the correct effort by watching
your heart rate? If you know how fast you’re your heart is capable of
beating while cycling (a maximum) and you know what your heart rate is at
complete rest (a minimum) you can find zones in between which give you a
decent picture of how hard you are working within a given ride.
Before describing how to determine these zones for your workouts, I want
to cover a couple very common myths regarding heart rates and training
zones. Let’s use an example… Your cycling friend Urs is telling you about
his ride last night and he says he did a solid aerobic cycling session
workout at 70% of his maximum, which he said was a 150 bpm average. You
ask yourself, is 70% good? Should I maintain 150bpm for an aerobic
session? Should I also maintain 150 bpm for running? How did he know his
maximum heart rate to begin with?
Myth: You have a single maximum heart rate number that can be applied
to all activities. When people talk about their Maximum Heart Rate
(MHR) what they really mean, whether they know it or not, is that MHR
really only applies to the type of activity you are performing and it is
not an absolute maximum. Your heart can easily beat 300 times a minute if
your brain tells it to do so, but you will hopefully never see this out on
a run or bike session. When we talk about MHR, we always mean activity
specific. You may find out your MHR for running is 190 bpm but on the bike
it may be only be 175. The amount and type of muscle fibers recruited and
the amount oxygen needed by the muscle groups contribute your brain’s
decision making on how fast the heart needs to pump. While you may use leg
muscles for both running and cycling, the bike supports most of your body
weight and overall recruits less muscle activity than running, resulting
in most people having a lower MHR for cycling than running.
Myth: You can use a formula to find your maximum heart rate.
As we've seen above, your MHR is different for every activity you perform.
In addition, it's also difficult to predict a number within each sport
with formulas such as the popular MHR = 220 –age or the newer MHR = 205
-.1/2 age. The fact is that even if the formulas would be based on a
single activity, there are wide genetic differences between individuals
that make these formulas too vague to be predictably useful.
As an example, my actual MHR for running is 4 beats less than what the 220
- age formula indicates, but my cycling MHR is 13 beats less. If I used
the formula's value to determine my training zones, then my "easy" heart
rate for a long bike isn't so easy anymore. Performance testing, not using
a formula, is the only really accurate way to find your MHR.
We now know that maximum heart rates are very unique to both individual
and activity, and it’s easy to see why Urs’ workout targets may not be
applicable to you at all. We will now also see how more accurate training
zones can be calculated instead of just simply measuring percentages of
our MHR.
Data Collection--Your Personal Physiology
In order to set up effective training zones, we need to know a few pieces
of information very personal to you: your Resting Heart Rate (RHR) and for
each sport, a Maximum Heart Rate (MHR).
Note: While I use a monitor for cycling and running, I don’t use one for
swimming. I’ve found it often difficult to get a good reading in the pool
and for training, you only typically get to see the monitor value while
stopped at the wall. While doing start and stop of intervals the heart
rate will lag behind the actual effort your are performing at thus giving
often false feedback to you. In the pool, I instead use the clock and
perceived exertion to determine how hard I am working.
Now, let's start measuring!
Calculating Maximum Heart Rate (MHR)
The test to find your maximums for running and cycling are going to hurt!
There's no other way to do it. In fact, the harder you work the more
accurate the measure is. The MHR test for running and cycling both consist
of the same protocol except one is performed on the bike and the other is
done while running. Before completing these maximal tests on your own,
please, please, (please!) get a thorough physical and a doctor’s
clearance. The level of exertion is significantly higher than just going
out for a healthy jog around the block. Even better would be to do the
test for the first time at a medical center where health professionals can
do a complete physical, blood work up, and the performance test (at least
for running) all together. Check your local hospital or university
athletic department for a contact for these centers.
The test consists of a short warm up, a gradual increase of intensity over
time, a final push to get a maximum, then a complete cool down. The reason
for the gradual build up is that brain doesn't signal the heart to work at
its true maximum for that activity instantaneously. So if you warm up for
5 minutes, then sprint your hardest for another minute, the heart still
will not have achieved a true maximum for that activity. Slow, steady
increases are needed to coax the heart to a true maximum.
Here is the actual test which works well for both running and cycling:
5 min. warm up slowly to a pace at the end where you are beginning to
breathe a little hard
5 min. maintain the pace, increasing a bit at the end
5 min. increase pace again to labored breathing.
5 min. on a gradual incline increase the pace from just breathing hard
to
breathing very hard. Transition directly into…
2 min. all out sprint on a steep hill to maximum speed!
1 min. push this max speed while still going up and hold for a minute
or
as long as possible!! Record MHR.
10 min. cool down at a very easy pace and stretch.
------------------
33 min. total ( 18 minutes hard, 15 minutes warm up/down)
Why include the hill climbing in addition to already killing yourself? I
found quite by accident that I could push a higher heart rate climbing
hills than standard flat running tests. I had an treadmill test performed
in a laboratory and another sprinting test around a track and both had
registered a running MHR of 179. A couple years later after moving here to
Switzerland I did basically the same test time with the final minutes on a
very steep incline and recorded a new MHR of 184. I felt the same level of
complete exhaustion in all tests, but with a new high value.
If you happen to have nothing resembling an incline in your area, you can
do the same test on flat ground, but keep in mind that it will probably
not be a true maximum for the activity, but a "level ground maximum."
I used to do a MHR test about twice a year, but now that I think I’ve
determined an accurate max, I only do it once a year. Your MHR for each
activity does not change with fitness level but may however, decline
slightly with advancing age.
Calculating Resting Heart Rate (RHR)
Compared with the previous test, RHR is pure joy to measure! At a point of
complete rest, simply take your pulse for 15 seconds, multiply by 4 and
record. The best time to measure this is first thing in the morning while
well rested and not in an overall overtrained state. Another option is to
wear your monitor overnight and look at the average. I've found both to
come out to be about the same number. One caveat is that if you really
have to pee first thing in the morning this can raise your RHR or if the
alarm clock scared the bejeezus out you, turn off the alarm and/or use the
toilet, return to bed for another 5-10 minutes and then record.
Some coaches recommend taking this measure for 3 consecutive mornings and
calculate an average. For me, I haven't found much difference day to day
as long as I'm about at the same fatigue level and I am getting the same
amount of sleep.
Unlike MHR, your resting heart rate does fluctuate with your fitness
level. Over the long term, people typically have a decline in RHR as their
fitness level improves, although genetics does play a part. I can train to
my wits end but I will never attain 5-time Tour de France champion Miguel
Indurain's RHR of 28. Your RHR also will change with your body’s fatigue
level, so taking your morning pulse often can indicate
overtraining/illness if you notice a rise of more than a few beats,
especially if higher readings last more than a few days.
Working Range
Why do we need to measure resting heart rate to calculate training zones?
It would be simpler to just find a maximum heart rate and base the
training on percentages from that maximum. But just as everyone has a
unique MHR for each activity, each person also has a unique RHR. To ensure
your basic survival, your heart rate never goes down to zero, so think of
the area between your resting and maximum heart rates as your available
working range for each activity. We'll base your training percentages from
this range instead.
Calculating Training Zones
The Karvonen formula takes advantage of the difference between your MHR
and RHR and is what we will use to derive our training zones based on your
personal measurements:
Heart Rate % of Usable Maximum = ((MHR – RHR) * P ) + RHR
where P is the desired percentage of maximum (1, .9, .8, .7, etc..)
As an example, I'll use my own personal measured data to calculate
percentages from 100% down to 50%.
My Measured Data
RHR = 44
MHR = 186 (running)
MHR = 176 (cycling)
Using the formula for 75% I get: 75% rate = ((186 – 44)*.75) + 44 =
151bpm
Here is the entire chart for my cycling and running:
|
Effort |
|
Bike |
Run |
|
100% |
|
176 |
186 |
|
95% |
|
169 |
179 |
|
90% |
|
163 |
172 |
|
85% |
|
156 |
165 |
|
80% |
|
150 |
158 |
|
75% |
|
143 |
151 |
|
70% |
|
136 |
143 |
|
65% |
|
130 |
136 |
|
60% |
|
123 |
129 |
|
55% |
|
117 |
122 |
|
50% |
|
110 |
115 |
So after performing these tests and calculations you have very
personalized target percentages for both cycling and running. In the next
article, I'll show you how to use these percentages to plan your training,
list more myths such as “fat burning range,” show some common pitfalls of
HR based training, and introduce some additional (free!) tools which
complement your HR monitor to have an even better picture on how your body
is performing during your workouts.
Until then, see you on the trail!
Scott
herrick_scott@hotmail.com
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