A quick course on the dos and don'ts of drinking to maintain
optimum performance and avoid dehydration and worse...

SO YOU’RE A LITTLE THIRSTY,  WHAT’S THE  BIG DEAL?

The facts about (de)hydration.

The bottom line (on the first line) is - drink drink drink! But make sure it’s the ‘right stuff’, right?  Well, what is the ‘right stuff”?  Milk? Juice?  Water?  Jolt?  Bud Lite?  Xena? Wild Turkey? Gatorade? Accelerade? Lemonade? Kool-Aid? And just what kind of  fluid “aid”  do you need, and when?  How much is enough? How much is too much? Here's some answers - just in time for the hot summer season ahead.

DRINKING  ON  THE  COURT – HOW   TO  CHOOSE   SPORTS   DRINKS

When is plain water just ‘not good enough’?

Whenever you are playing reasonably hard tennis for longer than 30 minutes on a typical Winter day or 15 minutes on a typical Summer day. People who sweat more should reduce that time. After that time, as a result of both exercise and sweating, you are likely to be losing both fluids and sodium (as salt) and other electrolytes (more on this later) at a rate that demands replacement. Water will replace the fluids but not the electrolytes - essential to the body's ability to regulate body heat and prevent cramps. You are also using your carb stores – the foods that provide you ‘quick’ or ‘instant’ energy - and, by the way, they also provide mental alertness and focus as well as the ability to sprint to the next shot.

So what should I drink?

First and foremost, the best sports drink for you  must taste good. Taste good to you - not to your buddy. This way you are much more likely to drink it, and drink enough of it.  And by “enough” I mean about 2 and a half cups approximately 2 hours before you play (not all at once, spread your drinking over a period of 1 to 2 hours before you play), another ½ cup about 15 minutes before stepping onto the court, then 1-2 cups (4-8 big gulps) at every change-over throughout your match. Don’t wait until you are noticeably thirsty – by then it will be too late (by too late I mean you’re setting yourself up for dehydration and cramps).

Second, choose a drink that won’t sit heavily in your stomach. Research has shown that more carbs is not better when it comes to sports drinks. Too much will often result in undigested liquid just sitting in your stomach and lead to an uncomfortable bloated feeling. So, how much carbs should be in a sports drink? About 6-8% of the total calories should come from carbs, preferably from a mix of glucose, sucrose, and fructose (with fructose - sugars that are derived mainly from fruits - making up the smallest portion) . Anything higher than 8% (commonly found in fruit juices, fruit punches, sodas, and some sport drinks) should be avoided or diluted with water.

Third, make sure your sports drink also has electrolytes in it. The most important electrolyte it should have is sodium (Na) – at least 100mg per quart to be most effective. Sodium helps your body retain water and thereby helps to prevent dehydration and reduce the incidence of cramping.  Anything less than 100mg per quart has been shown to be much less effective. If your drink doesn’t have that much sodium, you should take some extra salt - picnic salt packs are convenient.  There is also a product that can be purchased by your athletic trainer (not you) called Gatorlytes (made by the Quaker Oats Company - makers of Gatorade). It’s a concentrated dose of electrolytes that can be added to any drink, even plain water.  But you can simply use bouillon cubes dissolved in water. They are available at any grocery store.

Should I worry about too much salt intake?

Isn’t every dietitian telling the world salt is bad for you? If you have never been diagnosed with high blood pressure, if no one in your immediate family has a history of high blood pressure, and if you or a close family member has not been diagnosed as ‘salt-sensitive’ – then you probably don’t need to worry about the salt in your sports drink being ‘too much’. The effects of too little salt during exercise is much more likely to be harmful than too much. Remember Patrick Rafter’s quest to find out why he cramped so much? Studies showed he sweated out exceptionally large volumes of salt – so he learned he needed to take in much more electrolytes as well as fluid than the average athlete.

Do I need more salt in my sports drink? Do I need more carbs?

Go through this check list:

• Do you cramp ‘unexplainably’?

• Do your work out clothes have mysterious white stains and patches? 

• Do you get fuzzy-headed during matches?

• Do you lose focus?

• Do you fatigue quickly despite good cardio workouts? 

You  may be low on carbs and losing excessive amounts of salt in your sweat – so add salt to your foods; drink carbohydrate-electrolyte-enhanced sport drinks during play; and keep yourself well-hydrated off the court.  That means that, besides what you drink during practice, you should intake about 64 ounces of fluids daily from all sources (foods, fruits, veggies, beverages). Keep away from alcohol and caffeine as much as possible because they contribute to extra fluid loss and dehydration. And, for every alcoholic drink or cup of coffee that you drink, you should counter the effects by drinking an extra cup of water.  Now go pour yourself a big one - water, that is!

IT’S  QUIZ  TIME….

Here are 10 sample beverages available at your grocery store. Which would be the BEST all-around drink for your on-court hydration needs?

1          Water - no carbs, no sugars, low traces of sodium depending upon it’s source

2          Propel - 1% carbs, 3.5 mg sodium (Na)

3          Pedialyte - 2.5% carbs, 248 mg sodium (Na)

4          Gatorade - 5-6% carbs:  sucrose-glucose-fructose combo; 110 mg sodium (Na)

5          Powerade - 8-9% carbs: high fructose-corn syrup-maltodextrin (a glucose derivative); 73 mg sodium (Na)

6          Allsport - 8-9% carbs: high fructose-corn syrup; 55-80 mg sodium (Na)

7          Sprite - 10.2% carbs, high fructose-corn syrup-sucrose; 28 mg sodium (Na)

8          Coca-Cola - 10.7-11.3% carbs; high fructose-corn syrup-sucrose;  trace of sodium (Na)

9          Orange Juice - 11.8% carbs; fructose-sucrose-glucose;  2.7 mg sodium (Na)

10        Cranberry Juice Cocktail - 15% carbs, high fructose-corn syrup-sucrose; 10 mg sodium (Na)

The answer - either 3 or 4 - a non-alcoholic, non-caffeinated drink less than 8% carbs with at least 100 mg sodium (Na)

WHAT ARE THE EFFECTS OF NOT DRINKING CORRECTLY? 

What is hyponatremia? Can it happen to me?

Yes! Hyponatremia means ‘water intoxication’. More specifically, it refers to a condition of low (hypo) sodium (na) content in your body as a result of drinking too much (yes too much) water.  The sodium in your bloodstream enables the body to regulate fluid balance. When the electrolyte balance is disturbed, the body can absorb more fluid than your kidneys can excrete. What is the outcome? Milder cases are characterized by fatigue, nausea, and headache. In sever cases, drinking too much water while at the same time losing excessive amounts of sodium through sweat can lead to serious illness that results in seizures, coma and emergency hospitalization. Even professional tennis players have experienced this after playing prolonged matches in hot conditions.  Knowing enough to realize that it was important to re-hydrate, they simply drank lots of water - and suffered the consequences. The lesson - ensure that you drink fluids that will replace lost electrolytes as well as just the water content of sweat..

Why it’s not cool to get dehydrated

Dehydration is basically a condition where the body has an abnormally low water content. A healthy body consists of mainly water - approximately 65% in fact. It should not be surprising, therefore, that any disturbance of the balance of such a large part of the body should have a great impact on the health of the body. We all sweat but, because we have become so good at controlling our environment to maintain a comfortable temperature (through buildings and space heating and cooling to protect against climate extremes;  clothes design; etc.) the amount is usually so small that it evaporates from the skin quickly and without being noticed.

The body uses sweating to regulate body temperature. Warm-blooded creatures need to keep their body temperature within a very narrow and regulated temperature range to avoid discomfort and even life-threatening breakdown of functions. The optimum temperature for humans is 98.6 degrees. Even a few degrees higher or lower produces ill effects. Most of the skin contains sweat glands – small ducts that allow moisture to escape from the body. When the body senses that it is overheating, it opens the sweat glands and allows moisture to flow out. The moisture carries the body’s heat to the surface of the skin where it evaporates on contact with the cooler surrounding air. Those of you who remember your physics classes from school will remember that the process of evaporation (a liquid changing into a vapor) requires energy. The energy source in this case is heat energy. So, as the moisture (sweat) from our body evaporates into vapor, heat is absorbed from the body and cools us.

Liquid (the blood) is also used as the carrier of nutrients and oxygen to the muscles. When you sweat excessively – and thereby lose too much fluid - your heart has to work much harder to deliver nutrients and oxygen to your exercising muscles and it becomes much more difficult to keep your body from overheating which will lead to heat illness if the symptoms are not recognized. 

It is therefore vital to maintain the amount of liquid that is available to the body. The more you sweat, the more you need to replace the lost liquid in order to maintain your body’s ability to regulate its temperature.

Learn to recognize these early warning signs of dehydration:

•             Dark yellow, often smelly, urine (generally small quantity)

•             Sudden onset of extreme fatigue

•             Headache

•             Dizziness

•             Cramps

Initially, you will notice that your urine output is low, very dark yellow, and often strong smelling.  If you are exercising, you will become tired quickly or suddenly and your performance will deteriorate.  If you do not take counter measures quickly, you will probably start to cramp from the fatigue. These cramps will quickly progress from a little twinge to uncontrollable and totally incapacitating cramps. Other bad things will also occur quite quickly – you’ll get dizzy, light-headed, become uncoordinated, and feel cold even though you are actually very hot. This is classic heat exhaustion. If nothing is done to cool and rehydrate your body, you will lose consciousness and need immediate hospital treatment.  Sounds like fun, huh!?

How can I prevent dehydration?

First, be aware of what your body is telling you. If you are sweating, your body is trying to lose heat. Help it out by limiting your exposure to the heat or limiting the amount of work you are doing. Be aware that your body will overheat much more quickly in the hotter temperatures and humidity of summer (or if you fly off to a tropical island in the middle of the cold winter).  Higher humidity means that sweat on your body will not evaporate so easily into an already moisture-laden atmosphere and, therefore, your body will not be able to lose so much heat this way. If you find that moisture is dripping from your body, it means that you are losing an important heat-relieving mechanism – the heat loss caused by evaporation of moisture on your skin. Instead, your sweat will evaporate from the ground and cool the court – good for the court but not much good for you! So, instead of wiping off sweat with a towel at every opportunity, unless it is causing discomfort (by getting into your eyes, for example) leave the sweat on your skin to evaporate naturally and thereby provide the cooling that your body needs. Spread the sweat evenly over your body. It will evaporate much more easily as a thin film rather than as large droplets. Yes, I know, some of you are not relishing the idea of spreading sweat all over your body and leaving it there. But, trust me, sweat is a confirmed ‘turn-on’ (see below) and not something to be afraid of. The bottom line is that, the hotter and more humid the conditions, the more you should regulate the amount of exercise and exposure to heat. This preferably means doing less exercise or taking more frequent rest periods. But, I hear you cry, that’s not much use when you are playing tennis - rest periods are strictly limited by the rules and where you are playing on a court that is exposed to sun and humidity and rarely provides any shade. Then you have to take other protective measures.

How? Yes, you guessed it, by hydration.  Drink often. Drink lots. Drink the right stuff. What’s the right stuff, you ask? The best fluids are those with both carbohydrates and electrolytes as discussed earlier. The carbs provide some quick energy and also facilitate fluid absorption;  the electrolytes, especially sodium, will not only facilitate fluid absorption but it will also make you thirsty thereby prompting you to drink more. 

Don’t forget that hydration is a way of life – not something you think about and do only during your match. I’ve often heard players say, “What do you mean I’m dehydrated?  I did everything ‘right’ today” . My response is, “Yes, you did, but what did you do yesterday? And the day before that?  What are you going to do tonight? Tomorrow?” Dehydration doesn’t always ‘happen’ on the court – many times players are chronically dehydrated – they either don’t drink enough on a regular basis or they drink too much alcohol or coffee – or do so at the ‘wrong time’. Alcohol and caffeine are both diuretics – they make you urinate more frequently – thereby promoting the loss of body fluid. It is hard to ‘make up’ for regular fluid losses and generally poor hydration by suddenly consuming large quantities of fluids during exercise. Tests have shown that it is generally true that a healthy body “knows best” and strives to keep your body fluids in balance by making you feel thirsty when liquid is needed and urinating when it has an excess. However, it has also been shown that, once the normal balance is disrupted (by exercising without drinking enough, or drinking a lot of caffeinated beverages, etc.) the body has difficulty in getting back to a normal balance – and often takes several days to do so. A repeated cycle of too much/too little liquid intake can disrupt the body’s ability to balance fluid levels to such a degree that it loses the ability to naturally do so. So, go easy on the alcohol and caffeinated beverages, consume at least 64 ounces of fluids daily (in addition to the ‘extra’ that you need as a result of exercising and sweating), and drink the ‘right’ stuff. 

And what about downing a refreshing beer or two during a friendly match?  It seems like it’s quenching your thirst, right?  Whassamatta wid you??? Didn’ you learn nuttin’ from this good stuff??? Am I wastin’ my time here????

OTHER BENEFITS OF HEALTHY HYDRATION

Sweating is SEXY! 

Everyone sweats – it’s the natural way to be cool…

Why are ‘wet t-shirt’ competitions so popular with the guys? Why is a moist, glistening body so attractive to both sexes? Where do the expressions, “she’s so hot”, “he’s hot for her” come from? The fact is that body temperature actually rises (people get hot) when they are strongly attracted to someone. As a result, humans have a natural attraction to someone who is ‘hot’ – it suggests that they are strongly attracted to someone and therefore likely to be receptive to a little performance of the mating ritual...!

So, don’t worry about sweating (don't sweat the sweat???). Let it all ooze out and let nature take it’s course (I’m talking about losing heat here, ok?).

But if it is hot and humid out, the more skin you expose to allow evaporation, the more efficiently the body will lose heat (no, naked tennis, is not something I’m advocating!). The clothing that you wear will also have an impact on heat loss. If your clothing isn’t allowing evaporation to occur, then heat will be trapped in your body. And while that will make you hot, it won’t make you feel sexy!  So invest in some of the new light weight fabrics that ‘wick’ the sweat away from your body and onto the outside of the fabric where it evaporates, cools the fabric and, in turn, cools your body.

So what’s in your sweat?  Besides water, sweat also contains minerals – electrolytes like sodium, potassium, and chlorides. Does this sound like the ingredients listed on the label of your sports drink? If not, it should!

How much sweat can your body produce?  The body is capable of releasing from 2 cups (500 ml) to 3 quarts (3 liters) of liquid as sweat in a short period of time!  That means that, if you sweat heavily, you can dehydrate very quickly if you don’t drink enough.

Just how much sweat is “too much” – how much fluid loss can your body tolerate before your performance will begin to suffer?  About 2% of your body weight!  That may not sound a lot but it’s surprising how easily that amount of weight can be lost as sweat (the bad news for those who could stand to lose a few pounds – the body will demand that it is replaced or make you feel bad (literally) so sweating is NOT a weight loss program). You can try carrying a portable scale to your next tennis practice or tournament. If you weighed 175 pounds going into practice (or your match) and you weighed about 172 pounds after, then you lost enough fluid to negatively impact your performance that day! That means, you didn’t drink enough during exercise. Ideally at the end of your match you should weigh the same as you weighed at the start.

Fortunately, our body has a built-in protection system. When we sweat, the blood actually gets saltier and this triggers receptors in your brain that says, “I’m thirsty!” Don’t ignore these signals. If your body says, “drink!” then drink – and, now that you know what to drink, make sure you drink the right stuff.

Ever wonder why some people sweat more than others? Part of this is due to genetics and part is due to hydration factors. But a larger part is due to your fitness level.  The more aerobically fit you are, the MORE you will sweat, the SOONER you will begin sweating, and the LESS electrolytes you will lose. In the grand scheme of heat adaptation, this is very important. It means less chances of heat illness, less fatigue and better sports performance. But it also means that you will have to drink more fluids – and replace the lost electrolytes - to compensate for the loss from sweating. So, again, make sure you are drinking the correct mix of fluids and electrolytes.

TIPS FOR HEALTHY HYDRATION:

1.   DO remain hydrated at all times, off the court as well as on.

2.   DO weigh yourself before & after hard practice in heat – if you‘ve lost weight, drink 2 cups of fluid for every pound lost!!

3.   DO drink every 15 minutes during play - even if you don’t feel thirsty.

4.   DO make sure your sports drink has sodium (salt) and carbs in it. At least 100 mg of sodium and no more than 8% carbs.

5.   DO continue to drink after exercise.

6.   DO NOT overdrink during exercise – especially plain water.

7.   DO NOT drink so much that you gain weight during exercise.

8.   DO NOT drink caffeinated or alcoholic drinks before or during play. And keep them to a minimum at other times.

9.   DO NOT  limit your salt intake if you don’t have a health problem.

10. DO NOT  try to lose weight by dehydrating yourself. It is futile and can be very dangerous.

11. DO NOT  waste your money on 'oxygenated' or 'vitamin-enriched' water! 

Article by Dr Bonita Marks
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