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Weightlifting linked to risk of glaucoma
Now that the holiday feasting is over, many people step up
their exercise regimes to get back in shape. But new
research shows that you may want to take extra precautions
before hitting the weight machines.
Weightlifting may increase pressure in eyes
Researchers in Brazil found that lifting heavy weights,
especially while holding breath, is linked to an increase in
intraocular pressure, or pressure inside the eye.
They warn that this can increase the risk of glaucoma, a disease
in which unusually high pressure within the eyeball damages the
optic nerve and can result in permanent vision loss.
The results of the Brazilian study appeared in the September
2006 issue of Archives of Ophthalmology, a publication of the
Journal of the American Medical Association (JAMA).
Aerobics vs. weightlifting
Intraocular pressure is usually decreased after aerobic
exercises such as running and biking. But weightlifting appears
to have the opposite effect ? especially when combined with the
Valsalva manoeuvre, a weightlifting technique that involves
exhaling forcibly with the mouth and nose closed.
This phenomenon also occurs in individuals who play wind
instruments, particularly the trumpet, or when a person coughs
or vomits.
The study was led by Dr. Geraldo Magela Vieira, MD, of the
Institute of Specialized Ophthalmology and UNIPLAC School of
Medicine in Brasília, Brazil. Vieira and his team measured
intraocular pressure during weightlifting in 30 males age 18 to
40 who all had normal eye pressure and did not have glaucoma.
The bench press test
Participants did two versions of a bench press exercise, each
time lifting the weight four times.
For the first version, participants lifted the weight (first
repetition) and pressure was measured in the right eye.
Participants then lifted the weight three more times and during
the last repetition, held their breath.
For the second version, pressure was measured in the left eye
prior to beginning the exercise, and the participants lifted the
weight four times, breathing normally throughout. Eye pressure
was then measured during the last time (fourth repetition).
During the first round of exercise, intraocular pressure
increased in 27 of the 30 participants, by an average of 4.3
millimetres of mercury. During the second round, pressure
increased in just 18 of the men by an average of 2.2 millimetres
of mercury.
Holding breath raises eye pressure
Vieira and his team speculated that the increased eye
pressure could be due to the Valsalva manoeuvre and the "greater
intrathoracic (chest) pressure caused by the air retained in the
lungs when the subjects held their breath during intraocular
pressure measurement."
The authors also note that a certain type of glaucoma
(normal-tension glaucoma) is more common in individuals who are
subjected to frequent changes in eye pressure.
Caution to glaucoma patients
"Prolonged weightlifting could be a potential risk factor for
the development or progression of glaucoma,' they wrote.
'Intermittent intraocular pressure increases during
weightlifting should be suspected in patients with
normal-tension glaucoma who perform such exercises," they
conclude.
As always, check with your doctor or eye-care professional
before beginning any exercise regimen.