Properly Rehydrating Yourself

[DOOM]

Fluid Replacement: After warm-weather workouts, you must rehydrate.
Tags:cycling nutrition
Whenever you exercise vigorously for about 45 minutes or more on a warm day,
your body begins crying out for one simple - but critical compound - plain old
water. After all, when you exercise under steamy conditions, H2O tends to pour
out of your sweat glands in relative torrents, depleting your body of up to four
pounds of water in only an hour or so. And you definitely feel the effects of
this outpouring; your heart pounds too fast, your body heats up like an old Ford
radiator, and your legs are so numbed with fatigue that you feel like collapsing
in a heap. You need relief pronto!

Of course, you'll get that lost water back eventually, unless you're a chronic
under-drinker, but why not do it quickly? If you do, you'll skirt the lethargy
and pounding headaches which are associated with dehydration, cool your body off
more quickly, calm your heart, and FEEL much better. Plus, getting that water
back into your system will restore your blood volume to normal, and that will
mean that adequate amounts of oxygen and nutrients will flow to your leg muscles
for recovery. Prompt rehydration is essential!

But there's an art to rehydrating yourself - and also a science. And the
scientific research tells us that many athletes rehydrate themselves the wrong
way. After competitions and workouts, for example, you see lots of sports-minded
people guzzling down Gatorade, Isostar, plain water, or colas. Except for the
caffeinated variety of the latter, those beverages aren't bad for rehydration,
but they're definitely not the best!

Why aren't they so good? For one thing, those quaffables are pretty low in salt.
Salt?!!! I know, it's a bit of a paradox, but even though dehydrating exercise
tends to make your body fluids more - not less - salty, it's a good idea to have
some extra salt in your rehydration fluid. Follow along and we'll show you why,
and we'll also tell you how to make sure you are rehydrating yourself properly

How salt won
The advantages of extra salt in a rehydration drink were detected several years
ago by Dr. Hiroshi Nose and his colleagues at Yale University when they asked a
group of volunteers to dehydrate themselves by exercising for 90 to 110 minutes
under hot conditions. The rugged activity caused the exercisers to lose about
3.5 pounds of weight, most of which was simply water lost through the sweat
glands. A loss of 3.5 pounds works out to a deficit of over an ounce for each
two minutes of exercise - and almost a half-gallon in total.

After their pyrexic exertion, the athletes rehydrated themselves by drinking as
much plain water as they wanted over a three-hour period. However, for every 100
ml (about 3.4 ounces) of water they swallowed, the athletes also had to gulp
down a capsule containing .45 grams of salt. The volunteers had no idea what was
in the capsules, nor could they taste the salt as they drank.

On a separate occasion, the athletes exercised at the same intensity under
similar temperature and humidity conditions and drank as much water as they
wanted for three hours after the bout of exercise. Again, they were given one
capsule for each 100 ml of water, but this time the capsules contained small
amounts of sugar, instead of salt. As in the first case, the subjects weren't
aware of what was actually in the pills ('Role of Osmolality and Plasma Volume
during Rehydration in Humans,' Journal of Applied Physiology, vol. 65(1), pp.
325-331, 198.

And how did it turn out? Well, it wasn't even close: salt was the winner,
helping the athletes rehydrate themselves considerably more effectively,
compared to the sugar-plus-water drink! One of the benefits of the salt was that
it stimulated greater amounts of drinking. When the athletes took the salt
rather than sugar capsules, they freely drank about 1.22 litres of fluid during
the three hours post-exercise, versus only 1.1 litres of the sugary stuff. Of
course, getting more water into your body is a key component of the rehydration
process (the other part is keeping the water there once it's returned).

Why does salt make you want to drink? Perched under your brain is a little mass
of tissue called the hypothalamus, a crafty collection of nerve cells which -
among other things - checks the salt concentration of your blood. If your blood
is too salty, the hypothalamus 'tells' the conscious part of your brain that you
need to drink. Once you've located a water source and started gulping down H2O,
the incoming flow of water dilutes the blood (makes the salt in the blood less
concentrated), quietens down the hypothalamus, and decreases your desire to keep
drinking.

However, remember that after a bout of dehydrating exercise, you actually have
two problems: (1) your blood is too salty, and (2) your total blood volume is
too paltry, since a bucketful of your plasma has percolated into your sweat
glands and worked its way out of your body.

If you drink plain water to rehydrate, you address problem no.1 very nicely; the
incoming water dilutes your blood so that salt concen-trations come back to
normal. Unfortunately, that stupid old hypothalamus of yours thinks that
everything is okay and accordingly shuts down your desire to drink, even though
your total blood volume is still too low (the hypothalamus has no 'dipstick,' so
it can't really tell how much water is in your blood; it has to rely on
electrolyte concentrations to try to keep things regulated, and thus it can be
fooled fairly easily).

In contrast, if you drink salty water, salt will be absorbed into your blood
along with water, and your hypothalamus will call out to you, 'Hey! Drink some
more; your blood is still too concentrated'. By drinking more, you address the
big problem (no. 2 from above) and bring your blood volume back up to normal.
Later on, any excess salt can topple into your urine, and everything will be
great. You've got enough water in your body - and the right salt concentration
in your blood, too. Salty drinks are just better for quick rehydration!

Urine, diet colas, and sports drinks
And salty rehydration drinks are also helpful in another way. If you drink plain
water and simply dilute your blood, you actually encourage urine production,
causing you to lose body water at the exact time you are trying to build it back
up again. On the other hand, if you take in salty fluid, your kidneys become
repelled by the thought of peeing, and you keep more of your precious water on
board. In Nose's study, rates of urination were considerably lower in the
salt-water drinkers, compared to the sugary people. Overall, net fluid gain was
27-per cent greater when the athletes sipped salty potables!
But what about caffeinated diet colas and sports drinks such as Gatorade, which
are often used by athletes to rehydrate? A couple of years ago, researchers at
the University of Texas at Austin asked 19 college students to exercise at an
intensity of 60 to 80 per cent of VO2max under calescent conditions (32.5
degrees Centigrade, 40 per cent humidity) until they had lost 2.5 per cent of
body weight (slightly over four pounds). After the exercise, the subjects sat
for two hours under more comfortable conditions while drinking either plain
water, Gatorade, or Diet Coke. Instead of quaffing the drinks freely, the
students drank two approximately one-litre 'boluses' of fluid - one right after
exercise and another 45 minutes later. This meant that they drank almost exactly
the quantity of fluid (66 ounces) which they had lost via sweating ('Rehydration
after Exercise with Common Beverages and Water,' International Journal of Sports
Medicine, vol. 13 (5), pp. 399-406, 1992).

In this study, the subjects didn't rehydrate themselves particularly well, even
though they drank almost twice as much fluid as Dr. Nose's volunteers. For
example, Diet-Coke drinkers restored only 54 per cent of their body weight by
drinking the two boluses of Coke, while water-drinkers got back 64 per cent and
Gatorade drinkers returned 69 per cent. The big problem with Diet Coke was that
it encouraged far too much urine production - about 227 ml more urine, in fact,
compared to Gatorade (the caffeine in the Diet Coke may have been the culprit).
Even plain water caused more urine production than Gatorade, probably because it
diluted the blood more quickly.

Why did Gatorade fare better than water and Diet Coke? Well, Gatorade contains a
bit of sodium (more than water and Coke, at least), and sodium works its magic
in a couple of ways. First, as we continue to mention, sodium keeps your
hypothalamus from prematurely thinking that fluid levels are okay. In addition,
when sodium and sugar are present together inside your small intestine, they are
'co-transported' across the wall of the intestine - and into your body. This
transportation plan creates an osmotic gradient between the fluids in your
tissues and the solution which is inside your small intestine. Since the sugar
and sodium have rushed over to the tissue side, water tries to flood along after
it, osmotically attempting to dilute the salty, syrupy environment in your body.
You benefit because you get to 'keep' much of that water that flows inward.

Are sports drinks like Gatorade the absolute-best rehydrating drinks then? Well,
not exactly. Although sports drinks are sometimes touted as electrolyte
replacers, the things are actually pretty low in sodium. They do have more
sodium than cola, fruit juices, and (of course) water, which all have really
puny salt contents, but their salt concentrations are actually quite modest.
Unless you force yourself to drink like a bulldog, you're likely to get better
dehydration with something a little saltier.

No, you don't have to drink actual salt water (although 5 tablespoons of sugar
and 1 teaspoon of salt, added to a quart of plain water, make a pretty good
rehydrating - but not tasting - drink, and one which has about three times as
much salt as Gatorade). All you need to do is ingest some salty food (pretzels,
low-fat potato crisps) along with your Gatorade or other sports drink as you
rehydrate post-exercise (of course, don't load up on salt if your doctor has
advised you against it because of specific medical problems). Or, you can toss a
couple of pinches of salt into your sports beverage - and drink away!
As you rehydrate, remember that you can't just drink what you sweated out and
expect everything to be fine. For example, if you lost three pounds during your
workout/race, you might assume that taking in 48 ounces of fluid would get you
back to normal again without delay. That strategy just won't work! It ignores
the fact that you continue to sweat, lose water from your respiratory system,
and produce urine as you are rehydrating, all of which cancel out some of the
intaken water. About an hour or so after your exertion, you should be producing
light-colour urine of normal volume; if your urine is dark in colour, stinks, or
is small in quantity, you are simply not rehydrating adequately. Exercise
physiologists sometimes recommend that you drink at least a quart-and-a-half to
two quarts more than the quantity of water you think you lost by sweating. If in
doubt - drink!

Solid food can help you rehydrate, too
Don't forget that electrolyte-rich meals can also help with the rehydration
process. In research carried out recently at the University of Aberdeen, five
male and three female cyclists cycled in a steamy environment (34 degrees
Centigrade, 55 per cent humidity) until they had dehydrated them-selves by about
2 per cent of body weight. After the exercise, the athletes ingested either a
carbo-hydrate-electrolyte sports drink or else a standard meal comprised of 53
per cent carbohydrate, 28 percent fat, and 19 percent protein, along with water
(at a volume 1.5-times greater than the amount actually lost during exercise).

Total urine output was significantly lower after the meal, compared with the
sports drink, probably because of all the electrolytes (especially sodium and
potassium) naturally found in the food, which helped hold water in the body.
When only the sports drink was ingested, the subjects' body-water levels were
still down by about 10 to 11 ounces six hours after the exercise had concluded,
while the meal-and-water combination restored fluid balance to normal
('Restoration of Fluid Balance after Exercise-Induced Dehydration: Effects of
Food and Fluid Intake,' European Journal of Applied Physiology, vol. 73, pp.
317-325, 1996). Obviously, combining good water intakes with consumption of
electrolyte-rich foods can be a great way to rehydrate.

Finally, don't forget that drinking at the right rate DURING your workout or
race can also make it easier to rehydrate, because there will be less lost fluid
to replace post-exercise. Sipping 10 to 12 ounces of sports drink 10 minutes
before your effort and then five to six ounces every 15 minutes as you exercise
is the best way to keep your tank topped off. That will mean lower heart rates
during exercise, calmer body temperatures, better blood flow to your leg
muscles, higher performances, and - of course - quicker rehydration and return
to 'status quo' once your exertion is over.

During spells of warm weather, remember to use salt liberally and eat
electrolyte-rich foods between workouts, but not JUST BEFORE OR DURING training
or competition, when low-sodium sports drinks are called for. Never rely solely
on your thirst to determine if your hydration status is okay; thirst is a very
imperfect indicator of your body's water levels (remember how easily your
hypothalamus can be fooled). In hot weather, you should make a conscious,
determined effort to drink extra fluids and take in additional electrolytes. In
the two- to three-hour period after a dehydrating bout of exercise, try to drink
at least one and one-half times the weight of the water you lost during
exercise. For example, if you lost three pounds while exercising, that means you
sweated out roughly 48 ounces of fluid, and you should attempt to drink at least
72 ounces of rehydrating fluid within the two- to three-hour 'window' after your
workout.

http://www.pponline.co.uk/encyc/0138.htm

[howardDaDuck]

When I played football in high school they would give us a cube of salt before we started practice or a game.

[DOOM]

Originally Posted by howardDaDuck

When I played football in high school they would give us a cube of salt before we started practice or a game.

I thought it was a pretty good article. Seemed to clarify some things.

[howardDaDuck]

Yea I appreciate it,I always wondered why I would get a headache after working out.

[DOOM]

Originally Posted by howardDaDuck

Yea I appreciate it,I always wondered why I would get a headache after working out.

Yeah...And people seem to have some misconceptions about the wonders of Gatoraide also.

[howardDaDuck]

Cause it's been advertised that way.

[Hadeer]

I drink 16oz of ice water every morning. It is scientifically proven to BOOST your metabolism.

Then I drink whenever I am thirsty or know I can have water..It has been working pretty well so far

[DOOM]

Originally Posted by Hadeer

I drink 16oz of ice water every morning. It is scientifically proven to BOOST your metabolism.

Then I drink whenever I am thirsty or know I can have water..It has been working pretty well so far

Yeah I've been doing that also.

[Enrico]

After playing baskerball with my cousin, he was all sweaty and thirsty and downed a can of pepsi. He never finished it because he puked up. NEVER try and rehydrate yourself with soda. Bad idea.

I usually drink Vitamin water when I work out if I'm not drinking regular water. Gaterade is also good.

[Hadeer]

If you drink Vitamin Water, you mine as well drink pop. It's just as bad.

For me, water should be the only thing you hydrate yourself with, granted you are following a healthy and balanced diet. Gatorade is OK but I don't recommend it. For me, after weight lifting, I QUICKLY drink a shake I make (water + vanilla whey) then drink water as needed.

[SarahPesto]

I can go through about twelve 16 oz bottles of water a day and even more. I get real thirsty.

[Chaldean_Goddess]

I rarely drink water, but I wish I would drink it more. I use to be obessesed with the pink Vitamin water, and then I found out how bad it is for you and completely stopped drinking it.

[leomartin3213]

Nice post i must say. I have found a lot of useful and interesting information from here. From now one i would be more careful regarding my re hydration. Let's see how it affects.
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Leo
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