Supertraining

--- Lisa Day <[EMAIL PROTECTED]> wrote:

> Hi Ralph,
> 
> I looked up hypovolemia as this is a new term for
> me. I don't believe this is something I have.
> 
> Causes:Common causes of hypovolemia can be
> dehydration, bleeding, severe burns and drugs such
> as diuretics or vasodilators typically used to treat
> hypertensive individuals. Rarely, it may occur as a
> result of a blood donation.[1]
> I drink 2-4 litres of water a day; no bleeding or
> burns; and completely drug-free. Also a low resting
> pulse rate.
> 
> I run 5 km a day on various inclines (6 days a
> week); lift weights every other day, and stay active
> with hiking, mnt biking; swimming etc. I also eat
> cleanly and well : ) Im 36.
> 
> Thanks for your email reply.
> 
> Lisa Day
> BC Canada

It is great that you drink 2-4 liters daily but that
does not guarantee that you are not at times suffering
from chronic dehydration.

This is not an uncommon finding amongst athletes
especially if they base their fluid intake on thirst. 
 

The average sedentary non athletes needs a minimum of
2 liters daily just to maintain normal fluid
homeostasis.

On average the kidneys need about 1 liter daily to
filter the blood daily.  On the average a sedentary
(non sweating) individual loses at least another 1
liter daily in what is known as insensible water loss.


This fluid is lost through the lungs every time we
exhale (ever sit in a parked car when it is cold out a
note that the windows get fogged up? 

We also lose fluid through our skin even when not
visibly sweating.  

9 liters daily are excreted into our intestinal tract
to aid digestion daily, although approximately 95% is
reabsorbed through our colon.

************************
 <<A Primer on Fluids and Sodium

By Monique Ryan, MS, RD
This report filed June 10, 2004

In early 2004 the Institute of Medicine's (IOM) Food
and Nutrition Board released Dietary Reference Intakes
(DRIs) for water and sodium (potassium, chloride, and
sulfate recommendations were also included in this
report). You may have heard about these dietary
guidelines for Americans and Canadians, which are
designed for the average adult who may be sedentary or
mildly active, not for triathletes and cyclist who
training regularly, often for more than two hours per
session. In establishing the guidelines, the expert
panel reviewed the scientific literature for quality
of the research and the resulting data.

The IOM panel determined that male adults require 3.7
liters of fluid daily and female adults require 2.7
liters. 

The panel also decided that caffeinated and alcoholic
beverages could contribute to the total fluid intake
states noting that their diuretic effect seems to be
transient in nature. They also advise that drinking
that fluid intake should be driven by thirst and the
consumption of beverages at mealtime.

These recommendations will not fit endurance athletes
who should rely on my more than thirst to maintain
adequate fluid consumption. 
You are likely thirsty when your body fluid levels are
fairly low and there is an increase in sodium
concentration, not a good indicator for preventing
dehydration.>>
**************************

In the athlete who exercises these loses are greatly
increased.  An athlete can sweat 1+ liters of fluid
for every hour that they exercise. The 3 liters are
the minimum you should be drinking when not exercising
and then you probably need to add another 1+ liters
per hour of exercise, depending on the conditions
under which you exercise and the intensity of the
exercise. 

While sweating the athlete also loses a considerable
amount of sodium.

*************************
 <<Salt of the Earth
http://velonews.com/train/ 
By Monique Ryan, MS, RD
This report filed June 30, 2004

The IOM has recommended that sodium intake be at 1500
milligrams daily. This recommendation is based on the
fact that research supports that reduced intake of
sodium coupled with increased potassium intake can
help prevent the increase in blood pressure that
occurs with aging.

However, sodium sweat losses can vary greatly and be
significant during hard and long training sessions
outdoors. 

Athletes have had measured sodium sweat losses ranging
from 460 to 1800 mg sodium per liter sweat. 

How much sodium you lose in an hour of training is
also a product of your sweat rate. Some
well-acclimated triathletes and cyclists may be very
efficient sweaters and lose only one-half to one liter
of sweat per hour, while others may reach higher
levels of two or three liters per hour in hot and
humid weather, despite being acclimated.>>

********************************************

If you are losing a large amount of sodium through
your sweat and your sodium intake is low your body
will not retain enough of the water you drink to
maintain your blood pressure.  Just as too much sodium
may be associated with Hypertension low sodium can be
associated with hypotension or low blood pressure.   

How does this occur?  Well the needs to maintain a
sodium level of between 137 mmol/l and 145 mmol/l.  If
the sodium concentration levels begin to drop the
kidneys will dump  water and retain sodium to return
the equilibrium.   This can result in hypovolemia or
dehydration and is manifested in a low blood pressure.
 This can be compensated for with an increase in heart
rate.   

However when there is a sudden change in position such
as going from a lying position to a sitting position
or a standing position there can be a sudden
uncompensated drop in blood pressure causing a short
period of light headedness.  The hypotension then
causes several compensation mechanisms and the
dizziness passes.  If it were not for the compensating
mechanisms the individual would lose consciousness and
fall down.

In women this condition may be exacerbated by a mild
chronic anemia caused by their monthly menstruation.

By your own account you are a very active individual
and may in fact need more than 4 liters daily as well
as an increase of sodium in your diet.  The case cited
by someone  of correcting dizziness  by drinking V8
juice had less to do with the particular product other
than the fact that that particular juice contains
sodium.  

That is also the reason why the cardiologist made the
recommendation of increasing sodium to prevent
dizziness. 

The scientific way of testing for dehydration is to
check the urine specific gravity.   The non scientific
way, is to check the color of your urine.  Dark yellow
indicates a very concentrated urine (possible
dehydration) and very light yellow or clear urine
indicates a very dilute urine (adequately hydrated).

The exception is if you are taking high doses of
vitamins many of which will turn your urine a bright
yellow.

Ralph Giarnella MD 
Southington Ct USA