Swimming
Heart Rate
By Joanne
Maybeck
Heart
Rate Monitors Make a Splash!
Part Two
This
is the second of three articles about using a Polar heart rate monitor as a
fitness tool in aquatic exercise classes and personal
training.
Article One
·
Article Three
In Part One, we learned what a
heart rate monitor is, how to use it, and that monitors can be used in the pool
as a superior way to accurately and effortlessly measure heart rate in beats
per minute. This is a great tool for aquatic fitness instructors and personal
trainers who need to know participants’ and clients’ heart rates.
So
Now that I have my monitor, what
should my heart rate be, when I swim?
That depends on how you calculate it!
Traditionally, the equation “220-age” has been used to
estimate a person’s maximum heart rate. And, an intensity range of 60 to 90% of
a persons estimated maximum heart rate is considered to elicit a safe cardio
respiratory or aerobic effect during training.
Remember the poor pool
participants in Part One, who were frantically searching the wall chart for
what their heart rate should be, when the instructor asked them to take a pulse
rate? Most heart rate wall charts
follow the 220-age equation, and display the 60 to 90% range for various age
groups (20, 25, 30, 35, and so on).
A more accurate way to
calculate exercise intensity via heart rate is to use Karvonens formula. To do
this, you must know your resting heart rate. Find it by taking your heart rate for
60 seconds for three mornings before rising from bed, and average the
three. Then, calculate as follows:
220 – Age – Resting Heart Rate = Heart Rate
Reserve
Heart Rate Reserve x 50% + Resting Heart Rate = Minimum Training
Threshold
Heart Rate Reserve x 85% + Resting Heart Rate = Maximum Training
Threshold
But, is everyone’s maximum
heart rate “220 – their age”?
No
way! And, its true that both of
the methods above are based upon that assumption. So, where did 220 come
from? It supposedly relates
somehow to newborn babies maximum heart rate. But, no one has put a baby on a
treadmill yet, to work them to the max. And, research has established that
there may be a margin of error as large as 30 beats per minute in 220 based
formulas.
So, what is the best way to
estimate maximum heart rate?
World-class athlete and heart rate monitor “guru” Sally
Edwards calls this the Best-Fit Formula.
After years of searching for a better formula, she believes it to be the
most accurate to date. Here it
is:
210 minus 50% of your age
minus 5% of your body weight (pounds) + 4 if male and 0 if female = Estimated
Maximum heart rate.
But, exercising in the water throws another curve ball…
Are heart rates during aquatic exercise the same as on
land?
No! Aqua heart rates are 13% or 17 beats
per minute lower in water than heart rates during comparable land
exercise.
Why is my heart rate lower in water than on
land? There are five theories.
And they make good sense!
Temperature - Water cools the body with less
effort than air. This reduced effort means less work for the heart, resulting
in a lower heart rate.
Gravity - Water reduces the effect of
gravity on the body. Blood flows from below the heart back up to it with less
effort, resulting in a lowered heart rate.
Compression - Water is thought to act like a
compressor on all body systems, including the vascular system, causing a
smaller venous load to the heart than equivalent land exercise.
Partial Pressure - A gas enters a liquid more
readily under pressure. In water exercise, the gas is oxygen and the liquid is
the blood. So, more efficient gas transfer due to water pressure may reduce the
workload of the heart.
Dive Reflex - a primitive reflex
associated with a nerve found in the nasal area. When the face is submerged in water, this reflex lowers
heart rate and blood pressure. This reflex is stronger in some individuals than
in others. Some research suggests that the face doesnt even need to be in the
water for the dive reflex to occur. Some people experience its effect when
standing in chest deep water.
So,
how do I calculate my aquatic target heart rate?
Take a 13% or 17 beats per
minute deduction from your minimum and maximum training thresholds on land.
So, strap on your heart rate monitor, jump in the pool, and finally
know that you are exercising at a more accurate aquatic target heart
rate!
Joanne Maybeck is a fitness instructor and personal trainer in New
York City. She is certified by
ACSM, ACE, AEA, and AAAI/ISMA.
Joanne presents the CEC workshop Aquatic Heart Zone Training and will
soon offer on-line heart monitor education. She believes in training with
heart! For more about Joanne, please visit her
Internet web site or email her at FitNYC@aol.com |
