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For
example, after about 45 minutes of intense training, I
was also pushing my adrenal glands to produce excessive
amount of cortisol in response to the chronic amount of
stress my body was under. Cortisol, produced by the same
adrenal glands, is a hormone released under long-term
stress. Too much of it is not good, as this is not only
the fastest way to loose muscle mass and strength, but
also to age rapidly.
A
Harvard study examining how much exercise is beneficial
— and how much is not so good — demonstrated
that a cumulative exercise expenditure of 2000 calories
per week was the threshold for positive results. In other
words, after expending approximately 300 calories a day
during exercise, the positive effects of exercise on the
body slowly diminish. This is why, when looking at anti-aging
programs relative to exercise curves, we see a significant
drop-off in benefits past a certain level and duration
of exercise. This is explained by three biological mechanisms:
First,
after about 40-45 minutes of any type of exercise —
and especially intense weight training — so much
cortisol has entered the bloodstream that a shutdown of
eicosonoid production will begin. Eicosonoids are autocrine
hormones (such as prostagladins) that control all function
at a cellular level — i.e., inflammation, vasodilation/constriction,
heart rate, body temperature, immune function, etc. In
this case, cortisol secretion is a response to stress.
As eicosonoid production stops, the body is temporarily
allowed relief from pain, which it is sensing from too
much from intense exercise. For example, a shutdown of
PGE1 and PGE2 (pro-inflammatory/anti-inflammatory) prostagladins
would commence. Since pain in this case is relative to
some type of inflammation this would allow the body to
cope in the short term.
If
this persisted, however, all eicosonoids would shut down
and the body's function would come to a screeching halt.
This is the same dilemma that doctors face when giving
people corticosteroids. At first, all symptoms magically
disappear; however, within a few days T-cells begin to
plummet and heart irregularities and other key physiological
dysfunctions begin to appear. This is because the autocrine
hormone eicosonoids are being shut down at the cellular
level.
Because
of their power, these hormones also vanish in seconds.
They are, however, the primary activators and modulators
of all body functions and, once they shut down, other
hormonal systems (endocrine and paracrine) are sure to
follow. Small amounts of cortisol are not so dangerous,
because once dissipated, the eicosonoid production returns
to normal. As you might surmise, being in the gym 2-3
hours every day is an effective way of increasing to a
potentially counterproductive — and even dangerous
— level in the body.
Secondly,
during moderate exercise like walking, insulin levels
diminish and blood glucose levels arise in response to
the exercise-related increase in glucagon (the pancreas
releases glucagon to balance blood glucose levels). This
primarily glucose restoration mechanism works smoothly
as long as exercise is maintained at a moderate level.
But if the intensity increases, cortisol is released to
stabilize blood sugar and insulin levels. More cortisol,
more problems.
Third,
the more intensely you exercise, the more ATP you must
produce in the mitochondria for energy. The more ATP you
produce, the more free radicals you make, and a certain
percentage of those free radicals slip by the energy production
phase. Once "loose" in the body, these unpaired
electrons search out other electrons to latch onto and
oxidize. These excess free radicals search out essential
fatty acids (because of their high-polyunsaturation),
DNA (which they can damage), protein, fats and a host
of important vitamins that we call antioxidants. Making
too many free radicals is almost assuredly a passport
to aging because they can potentially damage so many essential
nutrients and biologically necessary compounds. Too much
exercise, along with eating too many calories, is the
most effective way of making excessive amount of free
radicals.
Now,
some of you might be wondering why you should lift weights
at all, if moderate aerobic exercise is more beneficial
for lower insulin levels, cardiovascular health and slowing
the aging process. Nonetheless, lifting weights does have
three wonderful biologically enhancing things:
First, it strengthens muscles and, therefore, assures
you greater functionality when you get older.
Second,
weight training prompts the hypothalamus to activate the
pituitary gland, secreting growth hormone and sending
other releasing hormones (and a second messenger known
as cyclic AMP) to the testicles to secrete increased levels
of testosterone. GH and testosterone work partially in
unison to repair micro-tears through protein synthesis
in muscle tissue. The result is slight muscular hypertrophy,
which increases strength.
Third,
the more muscle mass you carry, the more bodyfat you burn
— even at rest. This is a simple metabolic function
of the thyroid in response to the anabolic state you are
creating. Bigger muscles need more calories to function
and use calories more efficiently. Also, since loss of
muscle, strength and accumulation of bodyfat are all markers
of aging, increasing lean mass and strength and decreasing
bodyfat percentage moves your anti-aging report card up
three notches. Some other points:
*
When weight training, work out no more than 45 minutes
to minimize cortisol production. Skip the "easy stuff"
and go right into the multi-joint exercise.
*
Never do single — or double-rep sets. Keep it to
a minimum of six, and preferably 8-10 smooth, rhythmic
repetitions.
*
There should be an artistic ease to doing a set. "Intense"
doesn't mean shaking, squirming, screaming and jerking
your body around. These are all signs that the weight
is too heavy and that you're a novice with a big ego.
This stupidity also puts a huge stress on joints, but
more importantly, the neurological system is being taxed
and cortisol levels are going through the roof. Reps should
be smooth, rhythmic motions and contractions.
*
Do your aerobic training after weight training, so that
you can use maximum effort for heavy weights — and
to help better stabilize insulin and blood glucose levels.
Make it no more than 20 minutes of cardio on lifting days
and less than 30 minutes on off-days. The level of intensity
should always be moderate 60-65 percent of maximum heart
rate. You shouldn't have a burning sensation in your muscles
while doing aerobics. A really brisk walk is best suited
for your cardio needs.
*
Work your weight training schedule so that you are training
each bodypart once in an 8-9 day rotation. The body has
no concept of a seven-day week and, often, large bodyparts
need more rest time.
*
Don't hold your breath too much — this will increase
cortisol production (especially when under stress), raise
blood pressure and decrease immune function.
*
Find the exercise that suit your body type and stay with
them, possibly varying them intermittently. Don't do exercises
that stress your joints!
*
Enjoy your time in the gym, but make it brief. The more
efficient you can get in and out of there, the less cortisol
and excessive free radicals you will make. Also, when
you're in and out of the gym quickly, you'll look forward
to going back. After all, you want to have the same feeling
entering the gym at 60 that you did at 18.
-
Taken from Exercise
For Men Only (Paul Burke's Over-40 Fitness Column)
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