Re: Running in marathons impairs immunity

In article <[EMAIL PROTECTED]>,
 John 'the Man'  <[EMAIL PROTECTED]> wrote:

> Vitamins No Magic Bullet for Endurance Runners
> http://www.nlm.nih.gov/medlineplus/news/fullstory_14712.html   
>
[...] 
> 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. 
> 
[...]
> ------------------------
> 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. 
>
[...]
> Related info:
> <http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12959703&dopt=Abstract>
> ------------------------
> 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?

The headline of the article is stating that vitamins are not a panacea, 
a statement supported by the research it cites. And while marathon 
running may be somewhat off the beaten path (so to speak), endurance 
activities aren't really so uncommon as to be "bizarre circumstances".

And if _you_ didn't care, why post the article to begin with?  :-)

[snip]

> "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.

Your conclusion is faulty. The story states impaired immunity for a 
(depending on system) 3- to 72-hour period of time after...

    (A) Prolongued heavy exertion
    (B) For more than 90 minutes
    (C) Without a break
    (D) Without carbohydrate replenishment

...which the interviewed researcher attributes to the stress response 
kicking in. To reduce the stressor, it would appear that you could do 
any _one_ or more of the following:

    (A) Exercise less intensely
 or (B) Exercise for a shorter period
 or (C) Take breaks
 or (D) Keep your carbo stores up (don't bonk)
 or (E) Take care of yourself as you recover after exercise.

It doesn't follow that you should never work out for more than 90 
minutes.

> 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.

Once again, I don't see how you can logically reach that conclusion 
about the heart. Care to explain?

Van

-- 
Van Bagnol / v a n at wco dot com / c r l at bagnol dot com
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