The long haul

Improper hydration is not only dangerous: it can be fatal. A few simple techniques will make a major difference during your longer training sessions.

There is nothing magic about one hour. It is a general guideline. Some people who sweat more or are training more intensely may want to use these strategies for shorter workouts, while others may have adjusted fine to longer workouts. The three key factors that impact longer workouts are hydration, electrolyte balance, and calories.

Hydration

Hydration is very important. It only takes losing two percent (2%) of your normal water weight to start showing symptoms of dehydration, such as headaches, blurred vision, low blood pressure (hypotension), dizziness, and fainting. Losing more than 10 - 15 percent of your normal water weight can be fatal.

Exactly how quickly you lose water depends on a variety of factors, ranging from the intensity of the exercise to the general temperature and humidity. Sweat is a cooling mechanism for the body. The action of water evaporating helps remove heat and drop your core temperature. Humidity can inhibit this process and cause your body to heat more rapidly. Intense exercise also generates heat.

The easy way to determine how much water you need is to weigh yourself before and after exercise. For every kilogram you lose, you should drink at least one liter of fluid. The preferred way is to sip this amount during the exercise, rather than taking it all at once. When training in the gym your needs can be met by remembering to hit the drinking fountain every 15 - 20 minutes or by bringing a water bottle. For longer events such as hikes or runs, you can use fuel belts that hold bottles or special hydration packs.

Electrolyte Balance

Hydration can be dangerous without proper attention to electrolyte balance. One woman died after participating in a competition. The goal was to drink as much fluid as possible in a short period of time. The contestants drank only water. This excess amount of fluid caused the levels of sodium in her blood plasma to fall below normal levels, a condition known as hyponatremia. Low levels of electrolytes in the bloodstream inhibit the body's ability to move fluids and nutrients into and out of a cell. The condition can lead to brain swelling, coma, and in severe instances, death.

The risk of hyponatremia increases with exercise. During exercise, electrolytes are lost through the sweat. Sodium is the main electrolyte lost. Only small amounts of potassium are found in sweat, so sodium is the key electrolyte to replace during exercise. It is estimated that an individual can lose up to 1,000 mg (1 gram) of sodium through sweat every hour during intense activity in a hot, humid environment. Sometimes you may find after a workout that you have a white powder stuck to your skin and garments. This is salt from your sweat.

For these reasons, it is suggested you consume a beverage containing at least 400 - 500 milligrams of sodium per ½ liter in order to replenish electrolytes. Most sports drinks are specially formulated to contain higher amounts of sodium. It is important to read the label and understand how much sodium you are receiving. There are also salt tablets available to take during exercise in order to replenish electrolytes.

A good rule of thumb is to watch how well you are taking in fluids. If fluids are sitting in your stomach or you have a stomach ache, it may mean you are not getting enough electrolytes. Fluids consumed with proper amounts of electrolytes typically empty the gut more efficiently. Another sign you may not be receiving enough electrolytes is swelling. Some swelling during exercise is normal, but severe swelling is a sign that you should focus on receiving sodium as soon as possible to restore your electrolyte balance.

Calories

The final factor to consider is total calories. Your activity draws on various fuel sources during exercise, ranging from glucose in your bloodstream and glycogen in your muscles to fat. During prolonged exercise, however, your body's demands for calories are not met if you stay in a fasted state. While this can, over time, improve your body's efficiency at burning fat, it can also raise cortisol levels (a stress hormone) and lead to diminished recovery as well as increased muscle loss.

The issue with calories during training is related to digestion. A highly diluted intake of calories (i.e. lower calories per volume of volume) is less likely to make an impact on your body's ability to use those calories as fuel. A higher concentration of calories, however, can complicate digestion and cause stomach pain and nausea during the exercise.

Research suggests that the optimal amount to refuel is a 4 - 8 percent solution of carbohydrate, or approximately 16 - 32 calories of carbohydrate per 100 grams of fluid. Again, most sports drinks are properly formulate to supply calories within this range. For ultra long events lasting several hours (such as ultramarathons) a higher concentration and even solid foods may be necessary to supply the needed fuel during the event. Protein is not recommended except during extremely long (8 hours or more) events because it is more difficult to digest and may cause cramping and nausea. Protein may also increase your hydration needs.

While longer workouts can be dangerous without the proper strategy, a few simple steps will improve the quality of your training as well as enhance your recovery. You may get away with drinking nothing but water during your short workouts, but long workouts demand a focus on electrolytes and calories. This is why many sports drinks on the market are formulated specifically to help you stay fresh during the long haul.