A heat wave is a prolonged period of excessive heat often combined with excessive humidity. Officially, a heat wave is defined as three days of temperatures of 90°F or more, and that is exactly what has been transpiring at the end of June in the West coast, particularly in California, Arizona, and Nevada. In fact, six half-marathon runners in Southern California were hospitalized for heat-related illnesses on the final day of the month. A day earlier, paramedics responding to a Nevada home without air conditioning found an elderly man dead.

During a heat wave, the most important thing is staying hydrated. And, people who have a heart condition, are older than 50, or are overweight may have to take extra precautions. Our bodies are about 75 percent water and blood is nearly 80 percent water, so it is necessary to replenish what is lost every day. When water is not replaced, blood thickens, forcing the heart to work harder and raising the risk of a heart attack. Staying hydrated, then, is essential for heart function, but it also helps with alertness, controlling appetite, and generally improving all activity.

According to the American Heart Association, when the temperature and humidity are both above 70°F, we have entered the dehydration danger zone and it becomes necessary to sip water frequently and drink before, during, and after vigorous activity. To maintain a healthy fluid balance while in the dehydration zone, the following suggestions may help:

1. Keep a large water bottle handy to encourage you to drink water wherever and whenever.

2. Be sure to eat fruits and vegetables, which are great sources of water, daily not only to stay hydrated, but also to maintain optimal health.

3. Have a glass of water before each meal.

4. After each trip to the restroom, drink a glass of water to replenish your fluids.

5. Set reminders on your phone, watch, or e-mail to drink every hour.

6. Add a slice of lemon, lime, and/or mint to your water to give it some flavor without adding any extra calories.

A word of caution regarding energy drinks: because they contain large amounts of sugar and stimulants, they can be counterproductive to maintaining fluid balance. In some instances, they may even be dangerous; researchers found that brands with caffeine and the amino acid taurine significantly raise blood pressure and heart rate. There's no getting around it. Drinking water is always best.

How do I know if I'm properly hydrated?

To measure your hydration status, examine the color of your urine. If you're hydrated, your urine will appear to be a very pale yellow and almost clear (keep in mind that the water in the bowl will dilute it some). If your urine is much darker, like the color of tea or apple juice, this means that your body is dehydrated.

Sadly, many people are chronically dehydrated and don't even know it. Because they have ignored their body's thirst signals for so long, they don't easily recognize them and so they confuse thirst for hunger. Constant snacking, and especially constant sugar cravings, can be one hidden sign of a dehydration imbalance.

Another sign is allergies. With dehydration, histamine levels can increase and the immune system can become imbalanced, creating the perfect storm for dust, pollen, mold, and animal allergies to manifest. Digestive ailments, especially acid reflux and constipation, are another lesser known sign of chronic dehydration. Hydration is essential to keep all functions of the digestive tract running smoothly.

Chronic dehydration may also reduce blood supply and manifest in the brain as mental and emotional imbalances and in extreme cases, temporary mental impairment. The brain relies on a relatively large portion of the body's blood supply. Ongoing stress also increases dehydration in the body with high levels of circulating stress hormones, so dehydration and stress can be a vicious cycle. Stress also causes the body to get rid of fluids, the idea being that in a potential "fight or flight" situation, the body needs to be as light as possible. Staying hydrated and finding healthy ways to relieve stress can help break this cycle.

Illnesses

During periods of extreme temperatures, people are susceptible to three different heat-related conditions.

Heat cramps are muscular pains and spasms that usually occur in the legs or abdomen. Heat cramps are often an early sign that the body is having trouble with the heat. The American Red Cross suggests a person move to a cooler place when suffering cramps; once a comfortable position has been assumed, it is best to lightly stretch the affected muscle and gently massage the area. It is best to drink an electrolyte-containing fluid, such as a commercial sports drink, fruit juice, or milk, and if such beverages are not available, water. A person suffering heat cramps should not take salt tablets.

Heat exhaustion is a more severe condition than heat cramps. Heat exhaustion most often affects athletes, firefighters, construction workers, and factory workers but it may also impact anyone wearing heavy clothing in a hot, humid environment. Signs of heat exhaustion include cool, moist, pale, ashen, or flushed skin, headache, nausea, dizziness, weakness, and exhaustion. If someone is suffering heat exhaustion, the American Red Cross recommends they be moved to a cooler environment with circulating air. Help them remove or loosen as much clothing as possible and apply cool, wet cloths or towels to the skin. Fanning or spraying the person with water also can help. If the person is conscious, give small amounts of a cool fluid, such as a commercial sports drink or fruit juice, to restore fluids and electrolytes. Milk or water may also be given. Give about 4 ounces of fluid every 15 minutes. If the person's condition does not improve or if he or she refuses water, has a change in consciousness, or vomits, call 9-1-1.

Finally, heat stroke is a life-threatening condition that develops when the systems of the body are overwhelmed by heat and begin to stop functioning. Signs of heat stroke include extremely high body temperature, red skin that may be dry or moist, changes in consciousness, rapid and weak pulse, vomiting, and seizures. Do not hesitate; call 9-1-1 immediately. While waiting for assistance, immerse the person up to the neck in cold water if possible; if not, douse or spray the person with cold water or cover the person with bags of ice. The American Red Cross suggests you apply rapid cooling methods for 20 minutes or until the person's condition improves.

Source: American Red Cross.