Home-made sports drinks

All athletes know the importance of avoiding dehydration during exercise. When exercising for more than thirty minutes it may be useful to drink something that replaces sweat losses (water and electrolytes) and energy.

Depending on whether it is necessary for an athlete to replace fluid losses, replace energy stores or replace both fluids and energy, the athlete should choose one of three types of drinks – hypotonic, isotonic or hypertonic. These drinks can be made at home using your favourite squash or fruit juice.

Hypotonic drinks

Hypotonic drinks are absorbed into the body more quickly than plain water. They usually contain low levels of carbohydrates (sugars) – less than 3g per 100ml – and may have a little salt added. These drinks are thirst quenching and provide fluid but they do not provide significant amounts of energy.

Hypotonic drinks are useful when it is necessary to replace fluids quickly without a lot of carbohydrate – for example, when activity lasts less than one hour and is of low intensity. They can also  be useful if a high fluid intake and low calorie intake is required – for example, when exercising in a hot climate.

Recipe #1 – 100ml fruit squash, 900 ml water, 1/5th teaspoon salt (1g)

Recipe #2 – 250ml fruit juice, 750ml water, 1/5th teaspoon salt (1g)

Isotonic drinks

Isotonic drinks are absorbed as fast as or faster than plain water. In addition to replacing fluids, isotonic drinks provide carbohydrates – 5-8g per 100ml. These drinks are designed to provide some carbohydrate to fuel the muscles, and have a little salt added to enhance the absorption and retention of fluid in the body. Many commercial sports drinks fall into this category.

Isotonic drinks are good for replacing fluids and providing carbohydrates (sugars) if activity lasts more than an hour, such as team sports or endurance events. Drink before, during and after exercise.

Recipe #1 – 50-70g glucose or sugar, 1 litre water or diluted sugar-free squash, 1/5th teaspoon salt (1g) – dissolve the glucose or sugar and salt in 100ml warm water before adding the remaining 900ml cold water or sugar-free squash

Recipe #2 – 500ml unsweetened fruit juice, 500ml water, 1/5th teaspoon salt (1g)

Recipe #3 – 150ml high juice squash, 850ml water, 1/5th teaspoon salt (1g)

Hypertonic drinks

Hypertonic drinks have a higher carbohydrate content – usually more than 10g per 100ml – which fuels the muscles. Hypertonic drinks are absorbed more slowly than plain water. These drinks replace lost energy rather than replacing fluids and therefore are not an effective or fast way to rehydrate. Hypertonic drinks include pure fruit juice, many canned drinks and energy drinks.

Hypertonic drinks should be taken when energy replacement is a priority – for example after training or after a game. These drinks can be used to top-up your daily carbohydrate intake.

Recipe #1 – 400ml squash, 1 litre water, 1/5th teaspoon salt (1g)

Other drinks

Stimulant drinks – these drinks usually have a high carbohydrate content but also have other additives that supposedly provide more energy – such as herbs, caffeine, guarana, taurine, ginseng, or carnitine amongst others. There is no evidence that these additives have a beneficial effect on sports performance and they should generaly be avoided during sport.

Water – the drink of choice for many people because it is cheap and readily available. Water will replace fluid losses but will not provide any energy. Water is good for non-endurance events of low intensity, where carbohydrate replacement is not the priority. Large intakes of water will dilute the blood, which stimulates urine output and effectively dehydrates the body. Fluid overload can be minimised by adding salt to a drink.

For extreme or endurance events, such as activity in hot weather or marathon events (prolonged moderate to high intensity activity), seek specific advice regarding hydration.

Top tips for athletes

  • Choose a drink that best matches your needs – water, hypotonic, isotonic or hypertonic
  • Always take a full drinks bottle to training and competitions
  • Cool drinks are more refreshing and palatable
  • Start drinking early – about two hours before starting exercise – do not wait until you feel thirsty because by this time you will already be dehydrated
  • Immediately before exercise drink about 150-350ml, then continue taking small amounts of fluid (150-200ml) every 15-20 minutes
  • Start drinking as soon as possible following training or competition – after exercise athletes should aim to replace fluid losses within the first two hours of recovery (this is more important when multiple training sessions occur during the same day)

Even mild dehydration can reduce sporting performance. Dehydration can have physical effects including reduced muscular strength, increased perception of effort, fatigue and slowing of self-selected pace. Dehydration can also affect mental performance including reduced concentration, reduced skill or accuracy and reduced decision making ability.

Athletes should choose a drink they enjoy and which meets their needs to optimize sporting performance.

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Boost your energy levels

Eating good food (full of nutrients) regularly can give you the energy you need to undertake your day-to-day activities, as well as the extra energy needed for socializing or exercising.

Could you make some simple changes to your daily routine to boost your energy levels?

Top energy-boosting tips

1. Don’t skip breakfast

By the time you wake up in the morning your body has been without food for many hours, so it will need some fuel to recharge. Eat breakfast to re-fuel and to stop your energy levels from dropping even further during the morning. Breakfast will give your body an immediate energy boost and give you a good start for the rest of the day.

Good breakfast choices include:

  • a bowl of breakfast cereal with semi-skimmed milk and a 150ml glass of fruit juice – try to choose a breakfast cereal that is high in fibre and low in sugar and salt
  • porridge made with semi-skimmed milk and topped with fresh or dried fruit
  • a boiled egg with toast and a banana
  • fruit smoothie

2. Eat regularly

Try to eat three meals a day and top-up with healthy snacks between meals if you start to get peckish. Lunch3

Healthy snacks include:

  • Fruit – choose fresh, dried, canned or frozen
  • Flavoured yoghurt or milk
  • Cereal bar or oatcakes
  • Fruit buns, fruit loaf or malt loaf

3. Eat foods rich in iron

Eat iron-rich foods so that the body can make haemoglobin, the red pigment in our blood, which carries oxygen to cells around the body. Females need more iron than males.

Iron-rich foods include:

  • red meat – such as beef or lamb
  • breakfast cereals – many cereals have iron added (see the nutrition panel on the cereal box)
  • dried fruit – such as apricots and raisins
  • nuts and seeds – such as cashews and almonds
  • lentils, peas and beans – including baked beans

4. Keep well hydrated

If you sweat during everyday activities, such as shopping or childcare, this loss of fluids could cause dehydration. Sweat during exercise will certainly cause dehydration if the lost fluids are not replaced.

By the time you feel thirsty you are already dehydrated. Everyone should drink 6-8 glasses (1.2 litres) of fluid each day to avoid dehydration – more will be required during hot weather or exercise. Choose quick and easy drinks like water, tea, coffee, semi-skimmed milk, or sugar-free fruit squash to avoid dehydration. It’s not necessary to drink sports drinks if you are participating in activity. Fruit juice mixed with water, well diluted fruit squashes or juice drinks provide hydration and energy.

Making just a few simple changes to your daily routine could provide you with all of the energy you need for each and every busy day in your schedule.

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Hydration for sport & physical activity

Optimal hydration improves health and well-being. Hydration is an important consideration if you lead an active lifestyle, whether that be competing in sport, exercising for enjoyment and health or working in a physically demanding occupation.

During exercise, a range of physiological changes occur in the body to maintain the supply of energy substrates and oxygen, and to allow the removal of waste products, carbon dioxide and heat.

Drinking when you feel thirsty may be an adequate approach to staying hydrated, but some people may need to establish a personal drinking plan to establish their needs and monitor their hydration status.

Physical activity can lead to fluid losses of 1-3 litres an hour and fluid intake should be adjusted accordingly. Levels of hydration have a significant impact on performance and a person’s experience of activity (perceived effort). Dehydration can adversely influence decision-making, cognitive performance and reaction times.

To encourage activity and improve performance it is necessary to avoid dehydration. The loss of small amounts (5-8%) of total body water causes thirst, dizziness, lethargy and fatigue. Losses of more than 10% of total body water causes confusion, drowsiness and overheating. Severe dehydration can cause reduced blood volume, increased heart rate, reduced skin and muscle blood flow, impaired thermoregulation, headache and nausea.

Exercise performance is impaired when an individual is dehydrated by as little as 2% of body weight. The capacity to perform high-intensity exercise, which results in exhaustion within a few minutes, may also be impaired by prior dehydration.

The main reasons dehydration has an adverse effect on exercise performance are:

  • reduction in total blood and cardiac output – a reduced maximal cardiac output  is the most likely mechanism by which dehydration decreases a person’s VO2max
  • decreased blood flow to the skin to aid thermoregulation
  • decreased sweat rate
  • increased core temperature (above 40 degrees Celsius) – the body temperature will rise if it cannot dissipate al of the heat it generates during exercise, which could result in a range of clinical conditions – from heat cramps to heat stroke

Overhydration is possible if an athlete trying to avoid dehydration drinks too much water (more than can be lost through sweat). Excess fluids may dilute the sodium concentration in the blood which is also a potential health hazard. It is important to consider the amount of fluids consumed before, during and after exercise and to consider the composition of your drinks.

Before exercise – individuals should begin exercise adequately hydrated:  Drink 400-600ml of fluids in the two hours before beginning exercise

During exercise – drink sufficient fluid to prevent dehydration from exceeding 2% bodyweight: drink 150-300 ml every 15-20 minutes (volume depending on sweating rate) – by monitoring body weight before and after exercise you can tell if you drank too little, too much, or just the right amount. Each kilogram of weight loss represents about one litre of sweat loss. Also, if you are urinating less often than usual or your urine is a darker colour than usual, you may be dehydrated.

Water is generally a sufficient fluid replacement for exercise lasting 40-60 minutes and electrolytes will be replaced during consumption of a healthy, balanced diet. For longer lasting exercise a drink containing carbohydrates and electrolytes may better maintain performance. A drink containing a low concentration of glucose (<5%) will empty from the stomach more quickly and better facilitate rehydration.

Since every person will have different fluid needs, ask the following questions to establish a drinking plan that works for sport you practice and for each of the different situations that you may practice in (eg: warmer temperatures)

  • How did you feel during your training session or event?
  • How was your performance?
  • How much weight did you lose during this session? – your weight loss should usually not be more than about 2% of you total body weight
  • Did your fluid intake make you feel uncomfortable?
  • Did you spend time drinking when you didn’t need to?
  • Did you have to stop to pass urine?

There are a range of strategies for supporting people active in sport or physical activity to stay adequately hydrated, and an individual should find a strategy that suits their circumstances, including their sport and personal characteristics.

Information from the European Hydration Institute

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