From: terry@jgaltstl.UUCP (terry linhardt)
Newsgroups: rec.bicycles,rec.running,rec.sport.triathlon
Subject: Re: Sweat
Summary: Running Research News article
Keywords: too_much, gross
Date: 12 Aug 92 16:51:00 GMT
Followup-To: rec.running
Organization: The Lafayette Group, St. Louis, MO.

In article <1992Aug11.181600.13827@walter.bellcore.com>, kenl@origami.cc.bellcore.com (Ken Lehner) writes:
> 
> My problem is that I sweat more than I can replace during a long run, ride, or
> triathlon.  I once calculated that I lost 1 ounce per minute on a 1.5 hour
> ride, and 1 pound per mile during a run.  My body starts hurting pretty badly
> from the loss, and my bike starts rusting pretty badly, too.  My question is:
> can I do anything about it?  Is there some mineral/chemical imbalance in my
> system that causes me to sweat so profusely?  How can I find out?  Am I stuck
> by my genetics, or can I alter my diet somehow?  What is the body's maximum
> absorption rate for water?
> 

Interestingly enough, there is an article related to this issue in the
July-August 1992 issue of RUNNING RESEARCH NEWS. I will quote from
their copyrighted article entitled "Glycerol Lowers Heart Rates and
Helps Cool Runners' Bodies in Recent Nex Mexico Tests"

       ...runners usually attempt to drink more water while running
       in hot weather, but thwarting dehydration can often be a losing
       battle. For example, once water reaches the stomach, a typical
       drainage rate from the stomach to small intestine is only 
       10 milliliters of H2O per minute. That means that water
       absorption from the intestine into the bloodstream normally 
       doesn't exceed about 600 milliliters (around 20 ounces) per hour.

       Meanwhile, on a hot day the rate of water loss from sweating can
       approach 1.5 to two quarts per hour. That creates an unfortunate
       situation: A 140-pound runner drinking 20 ounces of H2O per
       hour and sweating out two quarts per hour will lose about 
       three pounds of water every 60 minutes...

       Running speed declines primarily because dehydration reduces
       blood volume. Less blood can be sent to the skin for cooling
       and to the muscles to fuel performance.  ...running at a
       quality pace is (and feels) much more difficult. For years,
       scientists have searched for some way to limit these potent,
       negative effects.

       Now, researchers at the Veterns Administrations Hospital in 
       Albuquerque, New Mexico claim that a safe, natural chemical can
       do the job. The chemical is glycerol, a three-carbon molecule 
       found in nearly every molecule of fat in the human body. When
       glycerol is ingested with water prior to exercise, blood 
       volume stays high, heart rates are kept under control, and
       hot-weather performance improves, say the researchers.

	    [ Here, the article cites how the study was done, which
	      was reported in "Medicine and Sciene in Sports and
	      Exercise", vol 24(5) Supplement, p. S157,1992). ]

	The actual protocol for glycerol consumption was as follows:
	150 minutes before exercise, the athletes began ingesting
	a 20-percent glycerol solution. 5 milliliters of this fluid
	were ingested for each kilogram of body weight....The
	actual dosage of pure glycerol was about 1.2 grams of glycerol
	per kilogram of body weight. Glycerol (also called glycerin or
	glycerine) can be found in most pharmacies.

	120 minutes before exercise, the athletes quaffed pure water
	(5 ml per kilogram of body weight). 105 minutes before
	exercise, the cyclistes gulped down a similar quantity of
	water. Then, 90 minutes prior to exercising, athletes 
	swallowed 1 ml/kg of the 20-percent glycerol solution, along
	with 5 ml/kg of plain water again (this was the last intake
	of fluid). The strategy was to simply drink large quantities of
	water, along with glycerol, so that the glycerol would "hold"
	this water in the body. Ordinarily, such large amounts of
	pre-exercise liquid would create ample quantities of urine,
	but glycerol - once it is absorbed, creates a high osmotic
	gradient which "drags" water into blood vessels...

	[ The article then talks about some side affects. Some 
	runners reported terrible headaches, and some runners have
	become nauseous after ingesting glycerol. In one study,
	44 % of cyclists who took glycerol *during* exercise became
	nauseated, bloated, or light-headed. They also warn that
	ingestion of large amount of glycerol might also cause
	cerebral dehydration. The article then suggests that the
	protocol for ingesting glycerol as described above might be
	about the right amount at the right times for avoiding
	problems, since none of the athletes in that particular
	study had any problems. ]

	[ The article ended with the disclaimer that more study needs
	to be done. However, it did suggest that we would probably
	soon see commercial sports drinks which contain glycerol. ]


My disclaimer. I don't know if this will help anyone. I have never
used glycerol, and probably never will. However, the article seemed
to address some of the concerns of the original poster.

-- 
  Terry Linhardt                ...!wupost!jgaltstl!terry 
                                terry%jgaltstl.uucp@wupost.wustl.edu