💾 Archived View for gmi.noulin.net › mobileNews › 1780.gmi captured on 2024-08-19 at 06:51:06. Gemini links have been rewritten to link to archived content

-=-=-=-=-=-=-

The Facts on Water and Exercise

2010-01-29 08:16:52

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 - 1 cup of fluid for every 15 minutes of exercise
Replenish fluids lost (2 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.

--- Mobile internet site for reading on mobile phones, smartphones, small screens and slow internet connections. ---http://mpggalaxy.mine.bz/www/BB/mobile_news/threads/index_last.html

Posted: 2010077@394.45

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

Eating for Exercise

By Timothy M. Brewi, B.A., D.T.R.

July/August 2002

1. Food Before Exercise

Most importantly, be sure you're well hydrated before exercise. Exercise performance suffers with as little as 2 percent loss of body weight due to dehydration. Drink at least 2 cups of water about 2 hours before exercise. Drink another 2 cups of water within 20 minutes of exercise.

Don't exercise when the body is depleted of nutrients (like before breakfast). Note that performing aerobic exercise on an empty stomach or when you're hungry does not increase the amount of fat you burn; rather, it may cause protein to be sacrificed as fuel.

For optimum exercise performance, be sure to consume a healthy, well-balanced diet all through the day! (For more information on healthy food choices, click here.)

Don't exercise immediately after eating, because the body shifts fluid away from muscles and into the gastrointestinal tract during digestion. The ideal time for fitness activities is about ...

o 1/2 hour after a light snack.

o 1 hour after a light meal, heavy snack, or meal replacement drink.

o 2 hours after a regular meal.

o 3 hours after a Thanksgiving-type feast.

Consuming sweets (such as honey, candy, or soda) immediately before exercise does not provide a quick burst of energy, but may cause a rise in insulin followed by a drop in blood sugar resulting in fatigue.

2. Food During Exercise

Most importantly, be sure to drink plenty of water during exercise. Drinking water during exercise does not cause upset stomach or cramps; whereas restricting water during exercise may cause severe dehydration and limit performance. Be aware that exercise blunts the sense of thirst. "If you wait until you notice your thirst, you're already becoming dehydrated." So whether you feel thirsty or not, drink 1/2 cup of water every 10-15 minutes. Ideally, exercisers should consume adequate fluids during activity so that body weight remains relatively unchanged before and after exercise.

Note that muscle cramps are not caused by inadequate salt intake, but by excess water loss through perspiration. Salt tablets will aggravate dehydration by drawing fluids into the stomach. Prevent muscle cramps during exercise by keeping well hydrated.

For people who exercise up to an hour in moderate environmental conditions, the most appropriate fluid to drink is cool water. The typical American diet provides ample electrolytes (sodium, potassium, chloride, and magnesium) to replace what is lost by sweat. However, persons who exercise strenuously for more than an hour or exercise in extreme environmental conditions (neither of which is recommended!) may require a sports beverage containing carbohydrates and electrolytes.

Don't consume food during exercise, because the body shifts fluid away from muscles and into the gastrointestinal tract for digestion.

3. Food After Exercise

Most importantly, drink more water! If you don't believe you lose much water during exercise, weigh yourself immediately before and after exercise. The difference is water loss. Ideally, exercisers should consume adequate fluids during activity so that body weight remains relatively unchanged before and after exercise.

Sorry, if you lost weight during exercise, the loss is not due to burning fat but to losing water. Consume 2 cups of water for every pound of body weight lost during exercise.

Note that muscle cramps are not caused by inadequate salt intake but by excess water loss through perspiration. Salt tablets will aggravate dehydration by drawing fluids into the stomach. Prevent muscle cramps after exercise (especially the night after exercise) by keeping well hydrated.

Don't consume a heavy meal in the first hour after exercise.

Do enjoy a snack or light meal about 30 minutes after exercise. The ideal post-exercise snack is light and nutritious, containing mainly carbohydrates and protein in a ratio of about 2:1. Examples:

o 1 cup of fruit juice with protein powder.

o 1 cup of 1 percent milk, fat-free ice cream, or nonfat yogurt.

o 1 apple with 1 inch cube of low-fat cheese.

o 2 slices of whole wheat bread with 2 thin slices of turkey, optional mustard.

To achieve the best results from exercise, be sure to consume a healthy, well-balanced diet all through the day!

--- Mobile internet site for reading on mobile phones, smartphones, small screens and slow internet connections. ---http://mpggalaxy.mine.bz/www/BB/mobile_news/threads/index_last.html

Posted: 2010077@396.51

Proper Hydration for Exercise - Water or

What and when athletes drink depends upon exercise duration and intensity

By Elizabeth Quinn, About.com Guide

Updated: June 29, 2009

Water is the most essential ingredient to a healthy life. Water has many important functions in the body including:

Transportation of nutrients / elimination of waste products.
Lubricating joints and tissues.
Temperature regulation through sweating.
Facilitating digestion.

Importance of Water During Exercise

Proper hydration is especially important during exercise. Adequate fluid intake for athletes is essential to comfort, performance and safety. The longer and more intensely you exercise, the more important it is to drink the right kind of fluids.

Dehydration

Athletes need to stay hydrated for optimal performance. Studies have found that a loss of two or more percent of one's body weight due to sweating is linked to a drop in blood volume. When this occurs, the heart works harder to move blood through the bloodstream. This can also cause muscle cramps, dizziness and fatigue and even heat illness including:

Heat Exhaustion
Heat Stroke

Causes of Dehydration

Inadequate fluid intake
Excessive sweating
Failure to replace fluid losses during and after exercise
Exercising in dry, hot weather
Drinking only when thirsty

Hyponatremia - Water Intoxication

Although rare, recreational exercisers are also at risk of drinking too much water and suffering from hyponatremia or water intoxication. Clearly, drinking the right amount of the right fluids is critical for performance and safety while exercising.

Adequate Fluid Intake for for Athletes

Because there is wide variability in sweat rates, losses and hydration levels of individuals, it is nearly impossible to provide specific recommendations or guidelines about the type or amount of fluids athletes should consume.

Finding the right amount of fluid to drink depends upon a variety of individual factors including the length and intensity of exercise and other individual differences. There are, however, two simple methods of estimating adequate hydration:

1. Monitoring urine volume output and color. A large amount of light colored, diluted urine probably means you are hydrated; dark colored, concentrated urine probably means you are dehydrated.

2. Weighing yourself before and after exercise. Any weight lost is likely from fluid, so try to drink enough to replenish those losses. Any weight gain could mean you are drinking more than you need.

Things that Affect Fluid Loss in Athletes

High altitude. Exercising at altitude increases your fluid losses and therefore increases you fluid needs.
Temperature. Exercising in the heat increases you fluid losses through sweating and exercise in the cold can impair you ability to recognize fluid losses and increase fluid lost through respiration. In both cases it is important to hydrate.
Sweating. Some athletes sweat more than others. If you sweat a lot you are at greater risk for dehydration. Again, weigh yourself before and after exercise to judge sweat loss.
Exercise Duration and Intensity. Exercising for hours (endurance sports) means you need to drink more and more frequently to avoid dehydration.

To find the correct balance of fluids for exercise, the American College Of Sports Medicine suggests that "individuals should develop customized fluid replacement programs that prevent excessive (greater than 2 percent body weight reductions from baseline body weight) dehydration. The routine measurement of pre- and post-exercise body weights is useful for determining sweat rates and customized fluid replacement programs. Consumption of beverages containing electrolytes and carbohydrates can help sustain fluid-electrolyte balance and exercise performance."

According to the Institute of Medicine the need for carbohydrate and electrolytes replacement during exercise depends on exercise intensity, duration, weather and individual differences in sweat rates. [They write, "fluid replacement beverages might contain ~20 30 meqILj1 sodium (chloride as the anion), ~2 5 meqILj1 potassium and ~5 10% carbohydrate."] Sodium and potassium are to help replace sweat electrolyte losses, and sodium also helps to stimulate thirst. Carbohydrate provides energy for exercise over 60-90 minutes. This can also be provided through energy gels, bars, and other foods.

What about Sports Drinks?

Sports drinks can be helpful to athletes who are exercising at a high intensity for 60 minutes or more. Fluids supplying 60 to 100 calories per 8 ounces helps to supply the needed calories required for continuous performance. It's really not necessary to replace losses of sodium, potassium and other electrolytes during exercise since you're unlikely to deplete your body's stores of these minerals during normal training. If, however, you find yourself exercising in extreme conditions over 3 or 5 hours (a marathon, Ironman or ultramarathon, for example) you may likely want to add a complex sports drink with electrolytes.

General Guidelines for Fluid Needs During Exercise

While specific fluid recommendations aren't possible due to individual variability, most athletes can use the following guidelines as a starting point, and modify their fluid needs accordingly.

Hydration Before Exercise

Drink about 15-20 fl oz, 2-3 hours before exercise
Drink 8-10 fl oz 10-15 min before exercise

Hydration During Exercise

Drink 8-10 fl oz every 10-15 min during exercise
If exercising longer than 90 minutes, drink 8-10 fl oz of a sports drink (with no more than 8 percent carbohydrate) every 15 - 30 minutes.

Hydration After Exercise

Weigh yourself before and after exercise and replace fluid losses.
Drink 20-24 fl oz water for every 1 lb lost.
Consume a 4:1 ratio of carbohydrate to protein within the 2 hours after exercise to replenish glycogen stores.

Source:

Consensus Statement of the 1st International Exercise-Associated Hyponatremia Consensus Development Conference, Cape Town, South Africa 2005. Clinical Journal of Sport Medicine. 15(4):208-213, July 2005.

Exercise and Fluid Replacement, ACSM Position Stand, American College Of Sports Medicine, Medicine and Science In Sports & Exercise, 2007.

Institute of Medicine. Water. In: Dietary Reference Intakes for Water, Sodium, Cholride, Potassium and Sulfate, Washington, D.C: National Academy Press, pp. 73 185, 2005.