|Energy, strength and stamina are composites of true health and lasting performance. These virtues embody the principle objectives of all athletes, and as the science of sports nutrition continues to evolve, thousands of active men and women are slowly but surely developing an understanding of biological medicine, optimum nutrition and the intelligent use of dietary supplements.
Water and its effect on exercise performance is crucial to understand. During strenuous or prolonged physical activity, the water content of all body compartments decreases as a result of fluid loss through sweating and insensible water loss from the lungs, especially at high altitude. A two percent loss of bodyweight via water loss can greatly reduce exercise capacity. Thats why everyone who works out or plays any sport needs to prehydrate, hydrate and rehydrate with filtered, clean pure H2O.
From Victoria to St. Johns, I have traveled extensively across our great land testing the body composition of thousands of Canadians. Young and old, active and sedentary. Using a method known as bioelectrical impedance (Tanita) I can calculate the percentage of lean mass, body fat and water in each individual, and also determine their ratio of lean mass to fat. Without question as men and women age, they lose muscle, gain fat and slowly dehydrate. The only exceptions to this rule (regardless of age) are those who incorporate strength training in addition to aerobics and who also drink plenty of water.
Electrolytes are defined as inorganic salts (acid or base) dissolved in both cellular and extracellular fluid. Important electrolytes include potassium, magnesium, phosphate, sulfate, bicarbonate, sodium, chloride and hydrogen.
Electrolytes carry both negative and positive electrical charges which affect the bioelectrical status of cells. They regulate intracellular fluid volume and control the pH of cells. pH is the symbol for potence hydrogen, and refers to the acidity of a solution. pH is measured on a scale between 0-14, with numbers below 7 referring to acid, and numbers above 7 referring to alkaline or base. The pH of blood is carefully maintained at a constant alkaline pH between 7.35 and 7.45. Human saliva ranges between 6.35-6.85, whereas the gastric juice of the stomach has a pH value of 1.2-3.0.
Electrolytes modulate fluid exchange within various fluid compartments allowing for a constant, well-regulated exchange of nutrients and waste products between the cell and its external fluid environment. Electrolytes affect nerve transmission, muscle action and gland function. They also maintain the permeability of the plasma membrane and regulate the acid and base qualities of body fluids and blood. Electrolytes are lost primarily through sweat and urine. Excessive water and electrolyte loss can impair heat tolerance, reduce exercise performance and induce severe cramps, exhaustion and stroke.
Regulating the acid-base balance of the body involves the prevention of excess hydrogen ion concentration coupled with the continuous formation of acidic waste generated through normal cell metabolism. All body fluids contain chemical buffer systems such as bicarbonate, phosphate, protein, hemoglobin and the bodys alkaline reserve. These substances help maintain acid-base balance, and when stressed, are supported through respiration and kidney function.
The effects of strenuous exercise leads to a temporary state of acidosis, caused mainly from increased carbon dioxide and the formation of lactic acid. As blood lactate concentration increases, pH can drop to as low as 6.8 in the blood, and in active muscle, to 6.4 or lower. At a pH below 7, athletes may experience nausea, headache, dizziness and muscle pain.
A recent article published in Medicine & Science in Sports & Exercise, describes how a group of scientists from the Department of Sports Science, Loughborough University, United Kingdom, examined the effects of ingesting a carbohydrate-electrolyte solution on athletes (versus a placebo) on muscle glycogen utilization during 90 minutes of intermittent high-intensity running. The main finding of this study was that the amount of glycogen in muscle used during exercise was reduced by 22% when a carbohydrate-electrolyte solution (6.9% carbohydrate) was consumed before and at frequent intervals during activity.
Intermittent high-intensity running involves running and walking at various intensities of effort and typifies the activity pattern of many sports. Consuming a 6-8% carbohydrate solution reinforced with electrolytes and vitamin C can extend exercise capacity and delay muscle fatigue. Serum insulin and blood glucose concentration is maintained for longer periods and blood lactate after 30 minutes of exercise is lower compared to a solution of water only.
Think of electrolytes as conductors of electromagnetic energy flowing through the body. Minerals are difficult to obtain and many athletes are either deficient in potassium and magnesium or consume inadequate quantities in relation to demand. This can lead to symptom patterns clustered with fatigue, impaired glucose metabolism, muscle weakness, cramping and twitching.
Medicine & Science in Sports & Exercise
Volume 31, Number 9 September 1999
Carbohydrate-electrolyte ingestion during intermittent-intensity running.
Volume 36, Number 6 June 1999
Refueling For Optimum Performance
Gregory Haff, MS, CSCS
Nutritional Needs of Athletes
Fluid and electrolytes
Staying Healthy with Nutrition
The Complete Guide To Diet & Nutritional Medicine
Elson M. Haas, M.D.