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Sports Drinks & Fluid Needs

by ADMIN on JUNE 21, 2012

Sports Drinks – they’re all the rage now. But are they worth it?

The short answer: Depending on when, why, and how you’re using them – Yes

When would sports drinks have NO benefit? If sports drinks are drunk during the day (not while exercising), they only add extra sugar and calories that your body simply doesn’t need. It’s best to stick with water during these times.

Also, if you’re working out less than 45 minutes, water is sufficient for good hydration. In fact, studies show that when exercising less than 30 minutes, fluid (water or otherwise) has no benefits to performance.

During exercise the body generates over 20 times more heat (energy) than at rest – and the only way to release the heat is through sweating. If you don’t have enough fluid in your system to help get rid of this excess energy, your body can over-heat quickly, resulting in poor performance, weakness, and dizziness.

So when it’s hot out, or you’re a heavy sweater, then you may lose a lot of your hydration. Even just 2% dehydration can decrease your performance.

The History

Sports drinks have been around since the 1960s when a Florida college football team, the Gators, went looking for a better way to hydrate their athletes in the hot, humid weather of the south. The coach approached a group of physicians at the college and explained his quest: To prevent the negative effects of heat-related illnesses he saw his athlete’s suffering from – and to help increase performance during games if possible.

The physicians came up with two primary reasons the athletes were declining in performance:

  1. Loss of electrolytes from excessive sweating,

  2. Depletion of muscle glycogen (stored form of carbohydrates), which leads to muscle fatigue and failure during long practices.

The result? A specially formulated drink with a mix of carbohydrates, sodium, and potassium – with a squeeze of lemon for flavor. After using this drink during practice and games, the Gators began winning almost all of their games in hot, humid conditions – and then went on to win the Orange Bowl in 1966 for the first year ever.

And what did they name the drink? Gatorade. After the team.

As you may have guessed, this drink went on to be the first sports drinks on the market and became the official sports drink of the National Football League in 1968.

The Science


In most sports, particularly cycling (Hermansen et al. 1967) and running (Williams 1998), the point of fatigue is closely linked to glycogen depletion in the exercising muscle. By both increasing muscle glycogen stores before exercise, as well as consuming carbohydrates during exercise enhances performance significantly – particularly in terms of maintaining a faster running and cycling speed and extending exercise time.

Studies have also found that carbohydrate sports drinks improve sprinting and delay fatigue of basketball players. Surprisingly, the players also sunk more baskets due to improved cognitive function and focus.

The amount of carbohydrate taken in is key. Too much and the gastrointestinal (GI) tract is overwhelmed, resulting in gas, bloating, or diarrhea. Ideally, men can take in about 50-90 grams of carbs per hour while women can take in about 35-60 grams per hour (total).

When to ingest carbohydrates is also important. Many studies also show that carbohydrate fueling should be started well before fatigue sets in – or it may be too late to gain benefits.

The type of carbohydrates consumed makes a big difference as well. Each type of sugar (glucose, sucrose, oligosaccharides, fructose) is absorbed via a different pathway in the intestines. If you take in too much of one type, the pathway gets overwhelmed and the rest of the sugar will just… come out (diarrhea!). So taking in a mixture of sugars is best since more will be absorbed (each via a different pathway). Interestingly, Fructose takes much longer to digest and absorb, so drinking juice or other pure fructose-sweetened beverages may lead to stomach upset and other GI issues.

Another benefit: Ingestion of carbohydrates will actually help your body absorb more water.


Along with water, sodium is also lost in sweat. This is the most important electrolyte when it comes to exercise.

Sodium, the most abundant cation, and chloride, the most abundant anion help with muscle contractions and nerve signaling (Salt is made up of NaCl, or Sodium Chloride). Without enough sodium, hyponatremia (the fancy work for low sodium) sets in, which can be very dangerous. Symptoms include nausea, disorientation, slurred speech, and confusion. Hydrating with water alone in a hot environment simply dilutes your sodium even further – causing more problems and potential heath issues. Not good for performance!

Sodium actually stimulates sugar and water absorption in the intestines and helps to maintain blood volume. It maintains blood volume by helping the body retain the fluids you drink – which in turn helps keep you hydrated for longer. While drinking only water can actually dehydrate you during extreme heat or long competitions/training. Without sodium, water is simply expelled by the body via urine and sweat.

Soft drinks contain virtually no sodium (1-2mmol/L) while sports drinks have about 30-90 mmol/L – an optimal amount to replenish normal sodium loss. If you’re a salty sweater (you can tell by how much salt is dried on your skin and cloths after a workout), you may even need salt tablets in a long distance race in addition to a sports drink. Talk to your coach to see if this is an appropriate option for you.

What about Coconut water? As you may have read in this article, coconut water is not the best sports drink for intense workouts lasting longer than 75 minutes. It simply doesn’t not have enough sodium to keep you well hydrated and performing your best.

Fluid Needs

The goal of hydration is to maintain body weight. On average, an athlete needs about 8-12 ounces of fluid every 15 minutes of exercise to maintain top performance and hydration.

Make sure you are well hydrated going into a competition or race. Check your pee! It should be a light yellow or clear. Drinking 8 ounce of fluids about 20 minutes before the race can also prime the intestines to be able to absorb more fluids during the race.

A Good Guide to your Fluid Needs:

Daily Fluid Needs: 30ml/kg

  1. (Your weight in pounds) / 2.2 = Kg body weight

  2. Kg x 30 = Total ml fluid needed per day

  3. (Total ml) / 240 = Number of cups you need to drink per day

Exercise Needs: (Added to your daily needs)

  1. Drink 2 cups 2 hours before exercise

  2. Drink 1 cup (8oz) 10 minutes before exercise

  3. Drink 1 cup every 15-20 minutes during exercise

* Weigh yourself before and after training/competition and for every pound you lost, drink 16 ounces (2 cups) of fluids.

Make Your Own

Don’t want to spend money on commercial drinks? You can make your own sports drinks with the right amount of sodium, potassium, and carbohydrates to fuel your workout.

Dawn Jackson Blatner, RD

3.5 cups water

1/2 cup orange juice

2.5 Tbsp honey

1/4 tsp salt

8oz: 50 calories, 14g cho, 160mg sodium

Nancy Clark, RD

1/4 cup sugar

1/4 tsp salt

1/4 cup hot water

1/4 cup orange juice (not concentrate)

2 Tbsp lemon juice

1.5 cups cold water

8oz: 50 calories, 12g CHO, 110mg sodium

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