Running in marathons impairs immunity

Vitamins No Magic Bullet for Endurance Runners
http://www.nlm.nih.gov/medlineplus/news/fullstory_14712.html   
"Reuters Health
By Merritt McKinney
Monday, November 17, 2003

NEW YORK (Reuters Health) - Loading up on vitamins won't help athletes
recover from a marathon or other endurance event, according to a North
Carolina researcher. 

But drinking a sports drink every hour during an extreme workout may
do the trick. 

The secret is in the carbohydrates -- mainly sugar -- found in sports
drinks like Gatorade, Powerade, 10-K and Quick Kick, according to Dr.
David C. Nieman of Appalachian State University in Boone."

SOURCE:
Interview with Dr. David C. Nieman of Appalachian State University in
Boone, NC.

IN RELATED RESEARCH:
Nieman DC. 
Current perspective on exercise immunology.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12959703&dopt=Abstract
Curr Sports Med Rep. 2003 Oct;2(5):239-42. Review. 
PMID: 12959703 

------------------------
This Article Concluded:
   
"Although moderate exercise may boost the immune system, research has
shown that pushing the body's limits during an endurance activity like
a marathon can temporarily weaken the immune system, Nieman told
Reuters Health in an interview. Because of this, endurance athletes
are at increased risk of illness following an event, according to
Nieman. 

The North Carolina researcher, a marathon runner himself, explained
that when people exercise for 90 minutes or more without taking a
break, carbohydrate stores in the body drop. The brain senses this
decline and releases large amounts of stress hormones, Nieman said. 

The release of stress hormones leads to "huge changes" in the immune
system, Nieman explained. This immune effect can last as little as 3
to 6 hours or as long as 3 days, he said. 

These immune system changes help explain why endurance athletes are at
increased risk of getting sick after a race, Nieman noted. 

Competing in a marathon or other endurance event is "like climbing a
mountain," Nieman said. It's dangerous, but "we do what we can to make
it safe." 

According to Nieman, the best way to keep the immune system strong is
to maintain the body's stores of carbs during rigorous exercise. 

There has been hope that vitamin supplements may help endurance
athletes keep their immune defenses up. But in three studies, Nieman
and his colleagues at Appalachian found that runners who took 1,000 to
1,500 milligrams of vitamin C each day for a week before a race fared
no better than runners who took a dummy placebo pill. 

Vitamin C had no effect on the negative immune system changes or on
stress, according to Nieman. 

Nieman and his colleagues also found that vitamin E was no help
either. In fact, too much vitamin E may be harmful to athletes,
according to Nieman."

------------------------
The Abstract Concluded:

"By far, the most important finding that has emerged from exercise
immunology studies is that positive immune changes take place during
each bout of moderate physical activity. Over time, this translates to
fewer days of sickness with the common cold and other upper
respiratory tract infections. This is consistent with public health
guidelines urging individuals to engage in near-daily physical
activity of 30 minutes or more. Risk of upper respiratory tract
infections can increase when athletes push beyond normal limits. The
infection risk is amplified when other factors related to immune
function are present, including exposure to novel pathogens during
travel, lack of sleep, severe mental stress, malnutrition, or weight
loss. Many components of the immune system exhibit adverse change
after prolonged, heavy exertion lasting longer than 90 minutes. These
immune changes occur in several compartments of the immune system and
body (eg, the skin, upper respiratory tract mucosal tissue, lung,
blood, and muscle). During this "open window" of impaired immunity
(between 3 and 72 hours, depending on the immune measure), viruses and
bacteria may gain a foothold, increasing the risk of subclinical and
clinical infection."

------------------------
Comment:

Here is another idiotic health news story that babbles on about
vitamins not being effective under a very bizarre set of
circumstances.  Who cares?

When it comes to exercise, a lot of people like to take an extreme
position.  Either they claim that they exercise because they do Hatha
Yoga (ie, the extreme of deficiency), or they insist upon running in
those 26 mile marathons (ie, the extreme of excess).  Marathon runners
are really an insane group of people.

What is important here is that "positive immune changes take place
during each bout of moderate physical activity. Over time, this
translates to fewer days of sickness with the common cold and other
upper respiratory tract infections."

The immune system is what keeps people from coming down with cancer as
we age.  And, it is moderate exercise that builds up your immune
system; rather than being enticed into running a marathon and other
extreme forms of exercise.

"Many components of the immune system exhibit adverse change after
prolonged, heavy exertion lasting longer than 90 minutes."  Thus, 90
minutes should be the maximum length for all workworks, particularly
for continuous exercise activities.

By paying attention to your exercise intensity, such as with METs, it
is better for your heart to cram more intensity into a shorter workout
than to perform low-intensity activities over a longer duration.
--
John Gohde,
     Achieving good Health is an Art, NOT a Science!

Health-with-Attitude is a support group for people 
trying to follow a Healthy Lifestyle.
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