Signs and symptoms vary depending on the degree of fluid loss, and can include fatigue, dizziness, heart palpitations, confusion, inability to sweat, decreased urine output and dry mouth and/or swollen tongue.
If exercise is less than an hour in length and not intense enough to cause heavy perspiration, drinking several ounces of water before, during and after the workout is enough to keep the body hydrated.
Research has shown that losing two percent or more of your body weight through perspiration causes extra strain on the heart, making it more difficult to pump blood to working muscles. This can lead to cramping, fatigue — and if enough fluids are lost, illness such as heat exhaustion and heat stroke, which can be life threatening.
Weighing yourself before and after exercise can help you to determine fluid loss. Here, the typical recommendation is to drink 20 to 24 ounces of water per pound of weight loss.
If engaging in high-intensity exercise lasting more than 60 minutes and in which sweating is profuse, sports drinks are typically recommended because they help replenish electrolytes.
Electrolytes are chemicals in the blood that help regulate body fluids and promote proper nerve and muscle function. When you perspire, you lose both water and electrolytes, which under normal circumstances are typically replaced through diet.
With excessive sweating, however, electrolytes and water can be depleted to the point where they begin to cause the body to weaken. Under these conditions, drinking water alone is not enough and can result in a serious and even fatal condition known as hyponatremia. Hyponatremia happens when sodium in the blood is diluted by excessive amounts of water, causing the cells to swell.
Some symptoms of electrolyte imbalance are irregular heartbeat, headache, fatigue, dry mouth, nausea, dizziness, confusion and even temporary paralysis and coma if left untreated. Muscle problems such as weakness, cramping, spasms or twitching can also occur. Diseases of the liver and kidneys, poor diet, certain medications, and medical conditions such as adrenal gland insufficiency and underactive thyroid can also disturb electrolyte balances, as can chronic, severe vomiting or diarrhea.
While beverages are a great choice to replace fluids when working out, during other times of the day fruits and vegetables can also help to keep you hydrated due to their very high water content. They are also great energy producing foods and packed with nutrients that are hard to get from other sources.
Because they are filling and low in calories, too, they are also ideal for weight control.
Marjie Gilliam is an International Sports Sciences Master certified personal trainer and fitness consultant. Write to her in care of the Dayton Daily News, call her at (937) 878-9018 or send e-mail to marjie@ohtrainer.com. Her website is www.ohtrainer.com.
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