How would you feel if I told you that I would give you $100, give or take $200?
For years, this is not unlike what we’ve done with heart-rate
training. Measuring exercise intensity using heart rate has suffered
from two major problems:
- Using relatively inaccurate formulas to make specific exercise-intensity recommendations
- Attaching discrete, seemingly all-or-nothing objectives to various heart-rate ranges
The overreaction to these problems has taken the form of proposing
that heart-rate training doesn’t matter when it comes to measuring
exercise intensity, especially with the rise in popularity of
high-intensity interval training, where the directive is a
straightforward “go as hard as you can.”
Not everyone needs to use heart rate to measure intensity, as their
goals may not be that specific or their starting health status may not
be questionable enough to warrant needing a definitive intensity range
to ensure safety when starting an exercise program. However, most people
will benefit from having some accurate gauge of exercise intensity to
help direct exercise efforts.
Age Ain’t Nothing But a Number…Until It Becomes a Bad Number
Using any formula that starts with age is problematic and introduces
huge error ranges that are potentially as large as the training zones we
are using. Any formula including any version of 220 – Age for maximum
heart rate calculation is going to be a mess for the same reason that
selling a single shoe size to everyone is going to be a problem. Not
every 50-year-old has the same fitness level, and maximum heart rate is
determined by more than just the number of years you have been alive.
Today, instead of having to rely on formulas, we have field tests
that measure specific points where the physiological response to
exercise intensity shifts. A
recent study
illustrates the unacceptable level of error when using a formula now
that we have the field tests. The formulas get it right for some people,
but get it wrong for enough people that if a better option is
available, it should be the preferred choice.
Out With the Inaccurate, In With the…More Accurate
The field tests directly measure two critical heart-rate points for
each individual. The first ventilatory threshold (VT1) occurs when
intensity reaches the point where the fuel for activity is coming in
equal parts from carbohydrate and fat. The second ventilatory threshold
(VT2) occurs when the rate of accumulation of lactate in the muscles
begins to exceed the ability of the circulatory system to recycle it.
Any time an individual works above resting heart rate, he or she is
improving fitness (if deconditioned), and at least maintaining fitness
(if already well-conditioned.) Beyond that, the two intensity shifts at
VT1 and VT2 can help define more personalized training progressions
because they are based on field tests of the individual’s response and
not formulas. (Details of the field tests and expanded details
surrounding VT1 and VT2 can be found in the
ACE Personal Trainer Manual, 5
th edition.)
Are You In the Zone?
Now for the second problem: Using heart ranges to define narrow
training objectives like the “fat-burning zone,” or the “cardio training
zone,” as if in one zone
all you are doing is using fat exclusively and the other zone is the only place you find cardiovascular improvements.
Working above resting levels but below VT1 will improve fitness in
deconditioned individuals and maintain it in those with an average
baseline level of fitness. Working between VT1 and VT2 will maximize
both caloric quality and caloric efficiency (explained in the next
paragraph) in the interest of prioritizing a metabolic response
during the exercise session. Working above VT2 will maximize increases in the ability to perform at a high level and prioritizes a metabolic response
after the exercise session.
As many people now realize, the big problem with the fat-burning zone
idea is that it emphasizes lower intensities because a higher
proportion of the calories burned come from fat. But high-
er doesn’t necessarily equal
high.
A large portion of a small number is still a small number. Working
between VT1 and VT2 (which will be higher than the old fat-burning
zones) maximizes
caloric efficiency through intensity that is high enough to burn a relatively high number of calories, yet low enough to allow
caloric quality, meaning a significant portion of calories come from fat. (
Note:
At VT1, the carb-fat mix for the fuel of activity is equal.) What does
this mean? A significant amount of fat is burned during the exercise
session and significant improvements in cardiovascular fitness are
achieved.
Working above VT2 will generally result in shorter-duration workouts
for those pursuing general fitness goals, as well as a higher portion of
carbohydrates burned as the fuel source for exercise. However, at this
intensity, the “after burn” effects begin to manifest and metabolism
gets a slight boost while at rest, which is when the body shifts to
using a higher portion of fat. Note that training above VT2 also
requires a high degree of psychological commitment as well.
Surrounded by Fat-Burning Zones
As a result, both of these zones are really “fat-burning zones.”
Between VT1 and VT2, you burn more fat during the exercise session.
Above VT2, you burn more fat after the exercise session. Shortly after I
first learned of these methods from an ACE exercise physiologist
several years ago, I began using them with my clients and it enhanced my
clients’ results by delivering more precise training-intensity
recommendations, which yielded better results without an excessive
investment of time for the clients.
Gone are the days where you need to know someone’s age to recommend
heart-rate training intensities. This evolution of cardiovascular
training intensity is a natural phenomenon in any field, as methods are
altered as understanding grows.
Source
It is important to be fit, everyone knows that. Your physical fitness has a big impact upon how you feel about yourself, and how much effort your body has to expend in order to keep working. Lack of physical fitness has supposedly reached an epidemic proportion in America, though the truth is that Americans are obsessed with physical fitness, and TV doctors and celebrities alike make a fortune through selling fitness videos and books to the public. Unless you’re planning to buy ‘em all and use them as weights to lift up and down every day, none of these will ever do your physical fitness any good at all.
