Staying Hydrated

During physical activity the body loses water primarily through sweat, even in cold weather or in water. The body has several mechanisms to protect itself from the negative effects of dehydration, but thirst does not occur until the person is already dehydrated!
The American College of Sports Medicine (ACSM) points out that as we get older, drinking enough water is especially important because with age our body is less able to regulate our temperature, putting us at increased risk of heat-related illness. Age also affects our ability to stay hydrated during exercise and our ability to recognize when we need more water.
A key to successful workouts is keeping well hydrated before, during and after exercise. The length of your workouts, heat, humidity and the amount you sweat are all major considerations for keeping your body in proper fluid balance.

Hydration Tips
Start hydrating early by drinking 1-2 cups of water in the morning
Keep a water bottle with you all day long
Drink before you get thirsty
Drink 1-2 cups of fluid 30 minutes before exercise
Drink ½ - 1 cup of fluid for every 15 minutes of exercise
Replenish fluids lost (2 ½ cups for every pound lost during exercise)
Keep drinking even after your thirst is quenched

Water vs. Sport Drinks
For exercise lasting under 45 minutes, water is your best choice. For the recreational athlete who may exercise 30-40 minutes per session, water is sufficient for hydration:

Water is easily absorbed
Water is the best choice to drink before moderate length exercise
Water is readily available and less expensive than sport drinks
Research suggests that for workouts consisting of at least 45 minutes of continuous exercise or high-intensity workouts of any duration – running, aerobics, biking and intense weight training – a sports drink may be beneficial in delaying muscle fatigue by providing your body with additional energy:

Sport drinks will replenish fluids while containing a small amount of carbohydrates and electrolytes
A steady source of carbohydrates during prolonged exercise fights off fatigue and enhances performance by fueling the muscles
Studies show that a solution containing electrolytes and carbohydrates may be absorbed more quickly and helps to retain fluids consumed after prolonged intense exercise
The taste of a good sport drink may encourage you to keep drinking

Over-hydration
Drinking too much water can cause problems such as water intoxication and, although this is not something most of us have to worry about, it does happen among many exercisers and should be something to be aware of. As the water content of the blood increases, the salt content is diluted; consequently, the amount of salt available to body tissues decreases, which can lead to problems with brain, heart and muscle function.
Symptoms include:
Dizziness
Nausea
Apathy
Confusion
These symptoms can also be attributed to dehydration, so it is important to know your body and know how much you are drinking.
Remember that you can get your daily water requirements from sources other than pure water. Your cup of tea counts! Water is the main ingredient in all drinks – carbonated drinks, fruit juices and even coffee. All these contribute to your daily fluid intake. Fruit and vegetables also have high water content, so proper nutrition is just as important.