Tag Archive | "fluids"

sports-drinks

Understanding Hydration

Your body is made up of between 65 to 75 percent water so a ten stone (140 pound/64 kilogram) person’s body contains around 42 to 48 litres of water! It’s no wonder then that virtually every nutritional expert places a high value on hydration, rehydration and avoiding dehydration.

Water is a number of functions in your body including:

  • Temperature regulation through sweating
  • Movement of chemicals around your body
  • Medium for chemical reactions
  • Lubrication of digestive tract
  • Elimination of waste materials and toxins
  • Integral part of all muscles
  • Provides a carrier medium for blood cells – known as plasma

 

Water is the most essential part of your diet. You can live for quite a long time without food as even the leanest person has a significant supply of body fat but, as we cannot store much water and it is essential for virtually every reaction that occurs in your body, you won’t live more than a few days without water to drink.

Staying Hydrated
As it is water your body needs, it is water you should drink but there are numerous opinions about how much water you need. The most common hydration recommendation is six to eight tall glasses of water a day; the equivalent of around two litres. Interestingly, this figure has absolutely no scientific basis and is not the result of any studies, medical journals or statistical research. It’s simply a figure that was proposed back in 1945 by the American Nutrition and Food Board that was adopted by just about everyone thereafter. That is not to say that these figures are wrong but only that two litres is an arbitrary number based on one organization’s opinion as opposed to scientific fact.

Rather than focus on the amount that your body MAY need, it is better to focus on what your body actually DOES need. The best determinant of your water needs are your thirst and your urine colour and output.

Thirst
Thirst should be  our best hydration indicator. Our caveman ancestors’ probably only used thirst to govern their water drinking habits. If you were thirsty, you needed to drink. Simple! The problem now is that,  because modern man often slakes his thirst with sweetened, calorie dense beverages, thirst and hunger signals can become confused. In other words, you might feel hungry but, in reality, you are actually thirsty but your brain gets the signals all turned around! This was not a problem for our non-sugary drinking ancestors. Subsequently, thirst has become a less accurate indicator of hydration. Because of this lack of thirst sensitivity, it is better to drink enough water to avoid thirst in the first place.

Urine Colour and Output
Other than your first urination of the day, most experts agree that your urine should be relatively clear, fairly copious and also odourless. Dark, smelly and infrequent urination can be a sign of dehydration and the less than rosy odour suggests a build up of undiluted toxins and waste-products. 

By avoiding thirst and making sure most of your urinations are a light straw-like colour and neutral smelling, you can be confident that your body as all the water it needs to maintain healthy metabolic and thermoregulatory functions.

Dehydration
Mild dehydration is common. A hard workout, too much coffee or alcohol, too little water or hot weather can all result in less than optimal water levels in your body. This is not a serious problem if this is a short term or infrequent occurrence but regular and/or long term dehydration can cause numerous performance and medical related problems.

Signs of Dehydration – in approximate order of onset and severity

  • Dry mouth (sometimes referred to as “cotton mouth”)
  • Reduced urine output
  • Dark, odious urine
  • Headache
  • Muscle cramps
  • Fatigue
  • Cessation of sweating
  • Hot, dry skin
  • Elevated heart rate
  • Confusion
  • Elevated core temperature
  • Heart palpitations
  • Unconsciousness
  • Kidney failure
  • Coma
  • Death

Too Much of a Good Thing?
While water is essential for life, too much water can actually be harmful to your health. Although very rare, some people have suffered from a condition called hyponatraemia, also known as water intoxication. This condition can manifest if you drink very large volumes of water, for example during a long distance running event where you consume significantly more water than you are losing by over taking on water at each and every feed station. This results in a dangerous dilution of essential minerals, collectively called electrolytes; specifically sodium. Sodium is essential for muscle contractions, regulating inter and extracellular fluid levels and pressure as well as controlling heart rate and rhythm. A significant enough sodium dilution can even prove to be fatal. Needless to say, this is a very rare occurrence and is usually the result of an underlying medical condition combined with an extreme excess in water or sports drink consumption.

Sports Drinks
No discussion of hydration would be complete without mentioning sports drinks. With so many on the market and so much advertorial information telling you what drink you should consume when, it can be very hard to choose a sports drink that is ideally suited to your needs.

The first question to ask yourself is, however,  do you really need a sports drink? If you are exercising for 60 minutes or less, are exercising for weight loss and have eaten properly in the hours leading up to your workout, I would suggest that plain water is more suited to your purposes. If, on the other hand, you are not eaten properly before training, are going to be working for 60 minutes or more and are not trying to burn fat during your workout, a sports drink is an acceptable way to stay hydrated. There are three main types of sports drinks:

  • Hypotonic
    With a very low amount of carbohydrate, a hypotonic drink is mostly about hydration and offers very little in the way of fuel. That being said, ingesting carbohydrates can suppress fat burning so water is the better choice if that is your exercise goal
  • Isotonic
    Containing around 6 grams of carbohydrate per 100 millilitres of water, isotonic drinks are the most common sports drinks. Usually engineered to provide a mix of slow, medium and fast acting sugars for energy plus essential electrolytes, an isotonic drink provides fuel and hydrating fluids in equal measure. Isotonic drinks are ideal for long workouts where a drop in blood glucose or muscle glycogen levels would result in decreased performance. However, the carbohydrate content and extra calories in these types of products would negate most of the benefits of a fat-burning workout.
  • Hypertonic
    Ten plus grams of sugar per 100 millilitres of water means that hypertonic drinks are more food than fluid. The high level of sugar may actually interfere with water absorption so these drinks are not ideal for helping you stay well-hydrated. If you chose to use a hypertonic drink, you should also consume plenty of plain water to make sure that you rehydrate as well as refuel.

The bottom line is that your body needs copious amounts of water to function properly and while soft drinks, coffee, tea, alcoholic beverages, fruits and vegetables can all contribute to your daily fluid intake, it is water that your body needs. Avoid getting thirsty, drink as much as you need to keep your urinations frequent and mostly clear, drink plain water during most types of exercise and use sports drinks wisely and you’ll be well on your way to avoiding dehydration.

 

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sauna suit

Fitness Tip or Myth – sweating & weight loss

sauna suitBack in the late 80’s and early 90’s it wasn’t uncommon to see people out exercising wearing suits made of PVC. These suits, normally with elasticated cuffs, ankles and neck, were designed to promote weight loss by increasing the amount of sweat produced by the wearer and were made very popular by those funky kids from the New York School for the Performing Arts in Fame but then so were leg warmers! Anyway…

The ‘’Sauna Suit’’ as it was known has almost all but disappeared but recently I spotted a “sauna vest” being promoted at a big UK leisure show so it looks like the misconception that sweating excessively causes fat loss is still alive and well. The theory that sweating causes increased fat loss has been around for a VERY long time – the history of saunas having contributed much to this mistaken opinion. It is an irrefutable fact that excessive sweating does indeed cause WEIGHT loss, but sadly, this weight is NOT fat!

Many sports use sweating as a way to “make weight” and get athletes into their required weight category. For example, a fighter who weighs 82kg could sweat off 2.5kg of weight to fight in the under 80kg division. The boxer would attempt to rehydrate after the weigh-in and, as a result, fight in a weight division below their current weight. Whilst this is an effective way of reducing scale weight, there is a possibility that the fighter may fail to be fully rehydrated by the start of the bout and this may result in a poor performance due to being still dehydrated. Essentially any hoped – for advantage would be lost. Jockeys often use a similar practice to ensure they are as light as possible to minimise the weight their horse will have to carry during a race and bodybuilders also try to “dry out” to maximise their muscular appearance for competition…

We can divide our scale weight broadly into two components…Fat Mass (FM) and Fat Free Mass (FFM). FFM is made up of water, muscle, bone and connective tissues like ligaments and tendons and we should always aim to preserve our FFM as it is quite literally the “good stuff” So really, we’re not correct when we talk about losing weight – we should be saying losing fat instead.

During exercise, or any other activity that causes a rise in body temperature (?!!) sweat lost can equal or even exceed one litre (just under 2 pints) in an hour. One litre of water weighs 1 kilogram (2.2 lbs) so quite possible to lose a substantial amount of weight during one hours exercise – especially in a warm climate. We sweat to reduce our body’s core temperature and prevent hyperthermia – the excessive build up of heat which may, if left unchecked, result in serious health problems. Water comes to the surface of our skin, evaporates, and takes with it some of the excess heat and as a result, we cool down.

The thing is, as soon as we drink water or our post- exercise beverage of choice, this weight will be put back on as soon as the fluid is back in our bodies…weight lost from dehydration is a very short term weight loss indeed! So clearly the degree of sweating while exercising has very little to do with long term fat loss.

In addition to having nothing to do with healthy weight loss, dehydration (the state of being deficient in water) also actually slows the burning of fat. The body perceives this reduction in water intake/increase in water expenditure as a possible drought, and drought is the natural pre-curser of famine. As a result, the age old “starvation response” kicks in and the body does all it can to preserve fat stores to keep us alive and well in periods of restricted food supplies! This is obviously not conducive to our goal of fat loss. We should do everything we can to avoid getting into a dehydrated state and this means we need to adopt a sensible approach to our water consumption…

Drink at least 2 litres of water a day.

Drink more if living in a warm climate.

Drink more still if lots of tea and coffee are consumed.

Consume an extra 250ml of water per 15 minutes of exercise performed.

Never wait to get thirsty – this means you are already 5-10% dehydrated

Watch out for high calorie sports and soft drinks which may well rehydrate you but will add extra energy to your energy intake and may interfere with fat loss. Water is best!  

It’s also worth remembering that water is ESSENTIAL to our health and well being. Just about every organ and process within our bodies relies on copious amounts of water…if water was on the healthy eating pyramid, it would make up the base because without sufficient water consumption our bodies will fail to function properly. We can survive a fairly long time without food but only a matter of days without water…

 The main factor to consider when we try to losing weight is that to burn fat, we need an energy deficit – which means less food energy in, and more activity energy out. The negative energy balance will result in fat loss, whereas losing water will merely result in weight loss.

So, in our quest to get slimmer for the coming summer -  ditch the sweat suits and extra layers of clothing, don’t worry about trying to “sweat the weight off”,  drink plenty of water, eat a little less while exercising a little more.

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water 2

Water 101

Water is a calorie free fluid that is essential for life. You can live quite a long time without food (depending on the size of your body fat stores) but only a day or so without water. Water makes up around 70 percent of your total body mass and to stop you getting dangerously dehydrated, your body uses thirst to tell you when to drink.

How your body uses water
Water acts as a suspension medium for the chemicals in your body. Without water, these chemicals would have no way to mix together or move around your body. For example, plasma is the suspension medium for your various blood cells. No water? No way to circulate oxygen carrying red blood cells, infection fighting white blood cells or clotting platelets.

Your body also uses water as a lubricant. Your joints, skin, eyes and digestive system function smoothly because of the presence of water. Like a car with no oil, your body would soon cease to function smoothly without water.

Water is also used to help detoxify your organs, Water is flushed though your digestive system and kidneys so that toxins can be eliminated via your urine. Have you ever noticed how much more smelly and dark your urine is when you are dehydrated? That’s the increased concentration of toxins you can smell. Staying well hydrated means that you are better able to flush these potentially harmful metabolic remnants out of your system.

Your body also uses water got temperature control. When you get too warm your body produces sweat which subsequently evaporates and helps dissipate heat. You can lose a lot of water through sweating. Vigorous exhalations also result in water loss. The breath you can see on a cold day is in fact water vapor. It’s still there when you exhale in warm weather – you just can’t see it.

So how much water do I need?
Opinions vary but consensus suggests that you need around two liters of water per day plus a further half a liter per 30 minutes of exercise. Drinking more is not likely to cause you any harm as excesses will be eliminated.

Tea, coffee and juices as well as fruit and vegetables all contribute to your fluid intake as well but as it’s hard to estimate just how much water these sources provide, you should simply shoot got two liters of water per day as a minimum. If you are getting thirsty, your body is telling you that you need to take some more water on board. Ignoring your thirst can actually desensitize you to the message your brain is sending and although you might not feel thirsty, you may still be dehydrated. As a general rule, your urine output should be regular, copious and mostly clear and odor-free.

Sports Drinks
Sports drinks are designed to rehydrate you and also provide you with energy in the form of carbohydrates. Different sports drinks contain different amounts of carbohydrates and contents vary from 2 to 10 grams per 100 milliliters. Sports drinks are great for long and grueling matches or workouts but are merely a source of unwanted calories for most general exercisers. Some “light” sports drinks contain no carbohydrate but use artificial sweeteners, flavors and colors. These chemicals are often linked to health problems like ADD, anxiety and hyper-activity and are generally best avoided. In the majority of cases, regular exercisers are best served by drinking plenty of plain water. If you find you are running low on energy during a workout of 60 minutes or less, the fault lies with your diet and not your choice of sports drink.

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