Health & Exercise Forum

The 27^th Steamtown Marathon is three months away and, despite the warm weather, many local runners are deep into training. With serious heat waves of summer, any prolonged endurance activity in minimal to moderate heat can be dangerous if not prepared. Adequate hydration is critically important, not only to those training for a marathon but also for other outdoor endurance activities such as cycling, hiking, long distance power walking, etc

Next to oxygen, water is the nutrient most needed for life. A person can live without food for a month, but most can survive only three to four days without water. Even though proper hydration is essential for health, water gets overlooked as one of the six basic nutrients. Dehydration occurs when the amount of water taken into the body is less than the amount that is being lost. Dehydration can happen very rapidly (i.e. in less than eight hours); the consequences can be life threatening and the symptoms can be alarmingly swift.

In the body, water is needed to regulate body temperature, carry nutrients, remove toxins and waste materials, and provide the medium in which all cellular chemical reactions take place. Fluid balance is vital for body functions. A significant decrease in the total amount of body fluids leads to dehydration. Fluids can be lost through the urine, skin, or lungs. Along with fluids, essential electrolytes, such as sodium and potassium, are also perilously depleted in a dehydrated individual.

The risk of dehydration is not limited to endurance athletes and outdoor enthusiasts. Dehydration is the most common fluid and electrolyte disorder of frail elders, both in long term care facilities and in the community! Elders aged 85 to 99 years are six times more likely to be hospitalized for dehydration than those aged 65 to 69 years.

Is water adequate to prevent dehydration? Will a sports drink improve my performance? While some answers to these questions apply generally to all, others vary according to the temperature, humidity, length of time and intensity of the activity and condition of the athlete. 

Proper hydration is essential for the comfort and safety of the recreational and serious athlete. Hydration is critical to maintain cardiovascular function, body temperature and muscle performance. As temperature, humidity, intensity, and duration of exercise increase, so too does the importance of proper hydration. Excessive sweating can lead to a loss of blood volume which requires the heart to work much harder to circulate you blood through your body.

Dehydration is a major cause of fatigue, loss of coordination, and muscle cramping leading to poor performance. Prehydration, (drinking before exercise) is the first step in preventing dehydration. Marathon runners, other long-distance runners, and cyclists often prehydrate1-2 days before a big event. Rehydration, (drinking during or after exercise) is the second step in preventing dehydration. While athletes may be more vulnerable to dehydration, all persons engaging in exercise would benefit from increased performance, delayed muscle fatigue and pain by maintaining adequate hydration. Proper prehydration would include drinking 12-16 ounces of water 1-2 hours before exercise.  Athletes with other health issues should consult their family physician before engaging in long distance endurance sports.

American College of Sports Medicine Hydration Recommendations:

• Eat foods high in carbohydrates and low in fat. Drink plenty of fluids between exercise sessions. The best fluids are plain water or fluids without sugar, caffeine or alcohol.
• Drink 17 oz or 2+ cups of fluid 2 hours before exercise
• Drink every 15 minutes during exercise.
• Keep drinks cooler than the air temperature. Drinks should be readily available.
• If you exercise more than 60 minutes, you may benefit from a sports drink containing a carbohydrate. The carbohydrate drink should not exceed 8% solution
• If you exercise more than 60 minutes, take 30-60 grams of carbohydrate per hour to delay fatigue and fuel muscle contractions.
• If you exercise more than 60 minutes, include (.5-.7 g per gallon) sodium in your drink of choice. This will also encourage additional drinking.
• Drink 24 ounces of water for every 2 pounds you lose after your workout. This is based on pre and post exercise weight.
• If you exercise more than 90 minutes, sports drinks may be helpful. 60 to 100 calories per 8 ounces of drink will help supply the needed calories for performance.
• Avoid caffeine. While the energy is good, it acts as a diuretic to rid the body of fluid. This is counterproductive for the high-level athlete.

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This article is not intended as a substitute for medical treatment. If you have questions related to your medical condition, please contact your family physician. For further inquires related to this topic email: drpmackarey@msn.com

Paul J. Mackarey PT, DHSc, OCS is a Doctor in Health Sciences specializing in orthopaedic and sports physical therapy in Scranton and Clarks Summit. Dr. Mackarey is in private practice and is an associate professor of clinical medicine at Geisinger Commonwealth School of Medicine. For all of Dr. Mackarey's articles, visit our exercise forum!