Revealed! The workout routines that won't improve your fitness...
Most workout routines designed to improve your aerobic fitness involve
exercising for 20 minutes or longer at a percentage of your maximum heart
rate - known as your training zone.
Quite apart from the fact that the formula
traditionally used to calculate your maximum heart rate is extremely
inaccurate, some workout routines can elevate your heart rate without
having any effect on your cardiovascular fitness. In other words, it's
possible to raise your heart rate, keep it there for 20 minutes or more
several times each week, and it won't improve your fitness in the slightest.
Workout routines
Most aerobic workout routines are based on the relative stress
they impose on your body. For example, the general rule for establishing
a suitable training intensity is to measure your VO2max. To improve your
aerobic fitness, you then follow a training program that corresponds to
a percentage of this maximum.
However, most people don't have access to the equipment needed to measure
their VO2max. Instead, they use their heart rate to establish a suitable
training intensity.
This is because during some forms of exercise, there's a link
between oxygen consumption and heart rate. During aerobic exercise, such
as running or walking for example, oxygen consumption and heart rate tend
to rise together. Yet the relationship doesn't hold true for all forms
of activity.
Nautilus exercise
Some evidence for this comes from a study carried in Medicine and
Science in Sports and Exercise. Researchers from Washington University
measured the effect of four months of strength training using Nautilus
exercise machines.
A group of 13 untrained males aged 40-55 took part in the study. During
each workout, which was carried out 3-4 times per week, test subjects
performed one set of each of 14 exercises.
During Nautilus exercise, the heart was working at 155 beats per minute,
which was approximately 80% of its maximum. However, despite training
in this way for up to four times each week, there was no significant change
in aerobic fitness.
This is because the large rise in heart rate was partly caused by an
increase in the production of hormones known as catecholamines (pronounced
cat-a-coal-a-meens). Adrenaline, for example, was roughly 4.5 times higher
during Nautilus exercise than treadmill walking at a similar oxygen consumption.
This doesn't mean that training with weights isn't a suitable
way to improve your aerobic fitness. After all, compound exercises such
as the squat and the deadlift place a large stress on your cardiovascular
system. What it does mean is that measuring your heart rate isn't
always the best way to gauge the effectiveness of your workout routines.
Reference
Hurley, B.F., Seals, D.R., Ehsani, A.A., Cartier, L.J., Dalsky,
G.P., Hagberg, J.M., & Holloszy, J.O. (1984) Effects of high-intensity
strength training on cardiovascular function. Medicine
and Science in Sports and Exercise, 16, 483-488
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