Google “heart
rate training” and you’ll get over 100 million search returns. Even by Google’s standards – that’s a
lot! Why are there so many returns? The fact of the matter is, fitness training,
no matter the program or workout, will be the most effective if you are able to
keep your heart rate in the zone that was intended for that workout.
In my
opinion, excellent and timely nutrition along with exercising in a range of “heart
rate zones” or “intensities” is key to meeting your body composition
goals. Notice I did not say weight – I HATE
the weigh scale because it is such a poor indicator, but that is another post!
Different
training programs and workouts require you to exercise at different intensities
in order to be the most effective. You
should familiarize yourself with the design of the exercise program you are
doing to understand what heart rate zone you should be in, and when. That said, here are the heart rate zones you
should know for training.
Healthy
Heart Zone (Warm-Up) = (50 - 59% MHR [Maximum Heart Rate] - this is a
great zone for you if you’re just starting to exercise. It can help to decrease
body fat, blood pressure, and cholesterol.
The Energy Efficient Zone (60% - 69% MHR [Maximum Heart Rate]) – also commonly referred to as the ‘endurance’ or 'recovery' zone. Training within this zone develops basic endurance and aerobic capacity. Exercising in this zone burns fat and allows your muscles to re-energize with glycogen, which has been expended during faster paced workouts. Long distance runners know this and it is the basis for their typical weekly “long slow run” where they train at a very low intensity and build endurance. The benefits of this are greatest when you exercise for long periods of time continuously – such as 2 to 3 hours.
The Aerobic
Zone (70% - 79% MHR) – training in this
zone will increase your body's ability to transport oxygen to, and carbon
dioxide away, from the working muscles, increasing your aerobic capacity. In this zone, your body is able to provide
energy to your muscles “on the fly” and produces few by-products like lactic
acid (the stuff that makes your muscles burn when working very hard). Aerobic metabolism is very efficient but it
is relatively slow. For runners,
increasing the speed one can run at and stay in this zone is a measure of increasing
fitness.
The
Anaerobic Zone (80% - 89% MHR) - Training in this zone will develop your lactic
acid system. Anaerobic means “in the absence of oxygen”. During these heart rates, the amount of fat
being utilised as the main source of energy is greatly reduced and glycogen
stored in the muscle is predominantly used. One of the by-products of burning
this glycogen is lactic acid. There is a point at which the body can no longer
remove the lactic acid from the working muscles quickly enough. This is your
anaerobic threshold (AT). Lactic acid interferes with energy production and so
our bodies are forced to slow down or sometimes even come to a complete
halt.
The Red
Line Zone (90% - 100% MHR) – training in this zone is only possible for a few
minutes – even for highly trained athletes.
Fast twitch muscle fibres which produce ATP (Adenosine Triphosphate) are
effectively trained at this level.
So how do
you calculate your heart rate zones?
Well there are a lot of different methods but most of us do not need ‘exact’
calculations in order to effectively utilize heart rate in our exercise
regimen. Here are some commonly used
approaches.
First,
estimate your Resting Heart Rate (RHR).
Take your heart rate for three mornings
in a row before getting up from bed. Once you have those numbers, take the
average of the sum: Morning 1# + Morning 2# + Morning 3# = ( X) (X) divided by 3 = Morning Resting
HR (MRHR) This is the single best indicator of your state of fitness. Once you have this
number established as a baseline, you can use it to understand more about
yourself than you can imagine. Take it again every once in a while, at least
once every two weeks. As your fitness
improves, you will most likely see that number going down. If you see an elevated number, it could mean
one or more of the following:
- You did not recover from a hard workout the day before
- You need more rest
- Your body has begun fighting off an oncoming illness
Next, you
need to estimate your MHR (Maximum Heart Rate).
The most
accurate method is to undertake a maximum heart rate stress test which although
relatively short does require you to push your body and your heart to the very
limit. Consult your physician before
doing this. There are also a number of
estimators published – here are a few.
The easiest
and best known method to calculate your maximum heart rate (MHR) is to use the
formula MHR = 220 – Age.
Research
conducted by Gulati et al. (2010)[3] identified that the traditional male-based
calculation (220-age) overestimates the maximum heart rate for age in women.
They investigated the association between HR response to exercise testing and
age with 5437 women. It was found that mean peak heart rate for women = 206 -
(0.88 x age).
A paper by
Londeree and Moeschberger (1982)[2] from the University of Missouri-Columbia
indicates that the MHR varies mostly with age, but the relationship is not a
linear one. They suggest an alternative formula of MHR = 206.3 - (0.711 × Age) Londeree and Moeschberger (1982) looked at
other variables to see if they had any effect on the MHR. They found that
neither sex nor race makes any difference but they did find that the MHR was
affected by the activity and levels of fitness.
A paper by Miller
et al. (1993)[4] proposed the following formula as a suitable formula to
calculate MHR MHR = 217 - (0.85 x Age)
Evidence
from Jackson et al. (2007)[5], identified the following formula as more
accurately reflecting the relationship between age and maximum heart rate. MHR = 206.9 - (0.67 x age)
Research by
Whyte et al. (2008)[7] came up with with the following formulae for predicting
maximum heart rates in both endurance and anaerobically trained athletes:
Male
athletes - MHR = 202 - (0.55 x age)
Female athletes - MHR = 216 - (1.09 x age)
Now, calculate your zones.
The calculation of a zone value, X%, is
performed in the following way:
Subtract your RHR from your MHR giving us your
working heart rate (WHR)
Calculate the required X% on the WHR giving us
"Z"
Add "Z" and your RHR together to give
us the final value
Example: The athlete's MHR is 180 and their RHR
is 60 - determine the 70% value
MHR - RHR = 180 - 60 = 120
70% of 120 = 84
84 + RHR = 84 + 60 = 144 bpm
While heart rate can be reduced at a given
intensity over time with an improvement in your fitness, there can also be a other
factors. Dehydration can increase
the heart rate by up to 7.5%, heat and humidity can increase the heart rate by
10 beats/minute, going up in altitude
can increase the heart rate by 10 to 20%, even when acclimatised, and biological
variation can mean the heart rate varies from day to day by 2 to 4
beats/minute.
Sources:
Running by John Stanton. http://www.runningroom.com/hm/inside.php?id=4395
Brian Mac Sports Coach http://www.brianmac.co.uk/
Polar USA http://www.polar.com
Dynamic Sport http://dynamicsportspt.com/