Taken from the NBCOlympics.com web page... http://www.nbcolympics.com
How athletic can shooting be?

SYDNEY -- Are shooters real athletes?
Some Olympians may sneer at the very idea that a shooter
could be considered a serious athlete. What about the
personal sacrifice, the hours of physical exertion, the
abstemious diet, the psychological mindset? Hey, they just
pull the trigger!
In truth, American shooters -- including the first gold
medalist of the Sydney Games, Nancy Johnson -- undergo
tough physical training just as runners, cyclists and
swimmers do. In fact, Johnson recently completed her first
half marathon, and she'll run a marathon next summer.
Johnson trains 45 miles per week now, and will be up to 80
prior to her marathon.
Johnson also does serious weight training. This lowers her
center of gravity and adds weight to her legs which improves
her balance for shooting. She told me that in the Olympic
Village, other athletes look at her well-developed leg
muscles and ask, "Hey, are you a cyclist?"
"No I'm a shooter," she replies.
They walk away perplexed.
So why the aerobic training, you might ask? Shooters need
to have a very low heart rate to give them enough time
between heartbeats to squeeze off a shot. Believe it or not, a
vigorously beating heart can throw off your shot.
Vigorous physical training slows a heart rate. Marathoners
are famous for having heart rates in the high 30s or low 40s.
Johnson wakes up with a heart rate of 45. "Almost dead!"
she says.
An untrained individual might have a heart rate in the
mid-70s. Cutting your heart rate in half can significantly
increase the time you have available to shoot, but running a
couple of miles a week won't do it. Forty-five minutes or
more a day of training is required to get your heart rate
down.
How does it work? First, athletes actually develop what is
called an "athlete's heart." That heart has a bigger main
pumping chamber, the left ventricle. The ventricle also
pumps a bigger volume of blood for each individual heart
rate. That means that an athlete pumps more blood than a
sedentary person. That gives them a much greater ability to
get oxygen to their muscles, which translates into much
faster times in aerobic events. This effect is pronounced
enough that an echocardiogram testing device can display
this bigger pumping chamber. An electrocardiogram may
also show strain or even an appearance of heart block.
The other reason athletes have a slower heart rate is that
their vagus nerve may discharge at a higher rate. This
overall vagal tone explains the relaxed look many athletes
have. Where your sympathetic nervous system can be
thought of as the adrenaline-charged, fight-or-flight mode,
the parasympathetic is the relaxed, resting and rebuilding
mode. Athletes live more in this parasympathetic mode,
well-trained shooters included.
Shooters also are very careful about their diet. They avoid
caffeine, which can raise heart rates, alcohol, nicotine and
foods that drive up blood sugar. Why? After a big load of
foods that increase your blood sugar level, there can be an
abrupt fall. During that fall, there is a discharge of
adrenaline which can increase heart rate and leave a
shooter feeling nervous or agitated.
Lastly, shooters need an extreme sense of calm. They get
that from sports psychology and from practicing a mantra
they use to quiet themselves before pulling the trigger. To
relax, Johnson does visualization, muscle relaxation and
yoga. "I live for my yoga class," she told me.
In all, shooters are tough and serious athletes who deserve
respect.