Dr. Dale Peterson, Dehydration, mineral deficiencies, heat exhaustion, heat stroke, sodium, magnesium, potassium, rehydration

Surviving the Heat

Surviving the Heat

© 2011 Dale Peterson, M.D and www.drdalepeterson.com

The summer of 2011 has rewritten the history of weather in a sizeable area of the United States. Oklahoma has experienced a record-shattering heat wave that, as I write this article, shows no sign of letting up. Over 95 % of the state is also in the midst of a severe drought. How severe? For most of the state this has been the driest summer, calendar year to date, and last consecutive 365 days since records began being kept in 1921. When one considers that we have been hotter and drier than the “dust bowl” days of the 1930s the extent of the crisis begins to sink in.

I have heard several people suggest that the heat and drought are indications that we are, indeed, facing a global warming crisis. Ironically, the most immediate cause of our current weather pattern is a relative cooling in the Pacific Ocean that is causing the jet stream to take a more northerly course. This is causing the rain we normally receive to fall on traditionally drier states such as Colorado and the Dakotas.

Why am I talking about the weather in a newsletter devoted to health and wellness? Because excessive heat causes more illness and death than all other weather related phenomena combined. That may seem hard to believe, but the average number of deaths in the United States annually from tornadoes is 82 – 130, rain and floods 100 – 160, hurricanes 38 – 63, hail 1, wind storms 60 – 115, lightning 100 – 156, winter storms and cold 130 – 200. The average number of deaths annually due to heat waves is 1000!

When one considers the maximum number of deaths due to a single weather event the difference is even more striking: Tornadoes killed 739 people in 1925, floods 2200 in 1999, hurricanes 6000 in 2000, hail 22 in 1981, wind storms 105 in 1972 and winter storms 500 in 1983, but the heat wave of 1980 was responsible for over 10,000 deaths!

I have been seeing a number of people with heat-related illnesses. They often report feeling weak and light-headed, but they may also report nausea, loss of appetite, and weight loss. Some recognize that they have suffered a heat stroke characterized by fever and loss of the ability to perspire, but most fail to make the connection between heat exposure and the symptoms they are experiencing.

Heat can cause a wide range of health challenges. The most common is mild dehydration, which results from a failure to increase water intake to compensate for greater evaporative losses in hot weather. It is important to recognize that one need not be visibly perspiring to be losing water at a rapid rate. The presence of visible perspiration is related to the relative humidity of the surrounding air. When the humidity is high, even a small amount of perspiration will be present on the skin. When the air is dry, however, water being released by sweat glands may evaporate too quickly to accumulate on the skin.

Mild dehydration comes on gradually and can persist indefinitely. More often than not it goes unrecognized, even by physicians. The symptoms are many and may include fatigue, weakness, loss of appetite, dry skin, flushing of the skin, infrequent urination, dark urine, chills, lightheadedness, thirst, and a dry mouth.

While thirst is the symptom of dehydration most easily recognized, it alone is not a reliable indicator of adequate water intake. Thirst may be a late sign of mild dehydration and, in fact, may not occur at all. Years ago, when my daughters and I set out to hike the Grand Canyon, we were advised by the park ranger that if we waited until we were thirsty to start drinking water we would risk dying along the way.

I recently saw a woman who was concerned about her health because she had lost 8 pounds over the preceding six weeks for no apparent reason. She had been feeling fine until two weeks prior to her visit when she began losing her appetite, feeling tired and experiencing light-headedness. I learned that she had been doing landscaping for several clients, which meant that she had been working in the outdoor heat. Her physical examination was consistent with mild dehydration and I advised her that she needed to increase her water intake. She was skeptical of my diagnosis and treatment plan, but agreed to drink more water. Two weeks later she reported that her weight had returned to normal. Her other symptoms had resolved as well.

If mild dehydration is not addressed it may progressively worsen. Signs of moderate to severe dehydration include an increased heart rate, more rapid breathing, decreased sweating, infrequent urination, low grade fever, extreme fatigue, muscle cramping, headache, nausea, and tingling in the extremities.

The management of moderate to severe dehydration requires staying in a cool area to minimize that further fluid loss. Rehydration will proceed more smoothly if electrolytes (body salts) are provided along with water. Water and electrolytes may need to be given intravenously, but this is only necessary if dehydration has progressed to the point that nausea and vomiting make oral fluid and electrolyte replacement impossible. I have seen many severely dehydrated individuals recover by using a homemade rehydration recipe, which was originally developed for use in underdeveloped regions where hospitalization and intravenous fluid administration are unavailable.

The four major body electrolytes are sodium, potassium, chloride, and bicarbonate. The rehydration recipe consists of 1 quart of purified water, 3/4 teaspoon salt (sodium and chloride), 1 teaspoon baking soda (sodium and bicarbonate), 1 cup orange juice (potassium), and 1 – 2 tablespoons of an unrefined sweetener such as barley malt, brown rice syrup, dried cane juice, honey (do not use honey in infants less than a year of age), maple syrup, molasses, sorghum, or Sucanat.

Not all heat-related challenges are due to lack of water intake. I have seen a number of individuals who were doing an excellent job of keeping themselves well-hydrated, but who had become mineral depleted. As we perspire we not only release water; we lose minerals as well. Sodium and magnesium losses are the most critical, but other minerals are lost and should be replaced.

Table salt, which is sodium chloride, has been so vilified in our society over the past few decades that most people have no idea that sodium is required to maintain fluid balance in the body. Sodium depletion will cause muscle weakness and light-headedness. Loss of balance, mental confusion, and body aches can also develop. Hyponatremia (a low level of sodium in the bloodstream) is not uncommon among people who are doing physically demanding tasks or exercising vigorously. One study of marathon runners found that 13 % were hyponatremic by the end of the race.

When I was young, people working in the heat routinely took salt tablets along with their water breaks, but this is rarely recommended today. Some authorities are so afraid of sodium that they recommend that people restrict their water consumption during long distance races to lower the risk of developing hyponatremia. Rather than facilitating water and electrolyte replacement, some marathon organizations are reducing the number of available water stations along the race route. The Houston Marathon, for example, cut the number from 30 to 15 in 2006, reducing water availability by half.

The most common mineral deficiency I see is that of magnesium. I believe this is due to the relatively low level of magnesium in the standard American diet. The richest dietary sources of magnesium are green leafy vegetables such as spinach, mustard greens, and Swiss chard, which are hardly everyday dietary staples in the average home. Other sources are raw pumpkin or sunflower seeds, beans, and whole grains. Few people include several servings of those foods each day. Because our bodies rarely have adequate magnesium reserves, even small amounts of magnesium loss will predispose to muscle cramping, headaches, and irregular heartbeats.

I once saw a new patient whose first words were, “I’m not very happy with you!” Since I had never seen the man before it was a very inauspicious start to our relationship.

“Why is that?” I asked. He explained that his wife had come to see me several weeks earlier and, as she was leaving, asked if I could recommend something to relieve her husband’s severe leg cramps. Learning that he owned a company that buried utility cables and that he worked in the outdoor heat, I suggested that he take a magnesium supplement.

“If I take the supplement you recommended I don’t get leg cramps, but if I skip it for a few days the cramps come back,” he explained. He was clearly expecting a “cure” in the sense of taking an antibiotic for 7 – 10 days to clear an infection.

I didn’t argue with him, but simply asked him a question: “How often do you need to put gas into your tractors?”

“Every day,” he replied. He paused for a moment to reflect upon what he had just said and then quietly whispered, “Oh.” Once he understood that he was losing magnesium every day he also grasped the need to replenish it on a daily basis.

I have seen many people who assumed they did not need to be concerned about magnesium because they were taking a calcium/magnesium supplement. A calcium/magnesium supplement is fine for normal situations, but it does not supply enough magnesium to replace losses when perspiring heavily. It is also important to understand that levels of magnesium may still be in the normal range when magnesium needs in body tissues are no longer being met.

Potassium loss is generally better tolerated because good dietary sources exist. Many foods contain potassium. Red meats, poultry and fish are good sources of potassium, as are soy products and veggie burgers. Vegetable sources include broccoli, peas, lima beans, tomatoes, potatoes, sweet potatoes, and winter squash. Citrus fruits, cantaloupe, bananas, kiwi, prunes, and apricots are good sources of potassium as are nuts and dairy products.

Potassium supplementation in the United States is an exercise in futility. The Food and Drug Administration limits the amount of potassium that may be placed in a nutritional supplement to 99 mg, an amount that is woefully inadequate to address the body’s potassium needs. The minimum daily potassium requirement for adults is between 1600 and 2000 mg. A serving of commonly available salt substitutes such as NuSalt or Morton’s Salt Substitute contains 530 mg. of potassium, which is comparable to the amount found in a medium sized banana.

Heat-related dehydration and mineral depletion generally develop gradually. In most cases, steps can be initiated to progressively replenish fluids, electrolytes and minerals over several days. There are, however, two conditions that appear suddenly when working or playing in hot weather that are life-threatening emergencies. They must be recognized and corrective measures instituted as quickly as possible. They are heat exhaustion and heat stroke.

Signs of heat exhaustion include heavy sweating, loss of skin color, tiredness, weakness, dizziness, headache, muscle cramping, nausea with or without vomiting, and fainting. The skin may feel clammy, the pulse may be fast and faint, and breaths will likely be rapid and shallow.

If someone is showing signs of heat exhaustion he or she should immediately be taken to a cool environment and encouraged to drink cool water or an electrolyte solution. Clothing should be minimized so that a large body area is exposed to the air and able to radiate the excessive body heat that is present. Taking a cool shower or sponging the skin with lukewarm water can facilitate the cooling process. Rest is a crucial element in recovery from heat exhaustion. The individual should not be allow to return to full activity until it is clear that body temperature has stabilized and optimum hydration has been restored.

If heat exhaustion is not recognized and treated it can quickly progress to heat stroke. Heat stroke is a very serious condition that can result in death or permanent disability if not addressed quickly. A heat stroke occurs because the body has become unable to regulate its temperature. In heat stroke the body temperature rises quickly. It is not uncommon for the body temperature to rise from normal to over 103 degrees in less than fifteen minutes. Readings as high as 106 degrees have been reported. Other signs of heat stroke include hot, dry skin, flushing, a racing and pounding pulse, a throbbing headache, dizziness and nausea. The individual may become confused or lose consciousness.

Because heat stroke is a life-threatening emergency it is appropriate to call 911 for immediate medical assistance. Do not wait for emergency personnel to arrive, but immediately begin taking measures to reduce the body temperature. If an air-conditioned room is unavailable at least get the individual into a shaded area. Remove as much clothing as modesty will allow and fan the person vigorously. If a water source is available, spray or sponge the body to increase evaporative heat loss. Under no circumstances allow the victim to drink beer or another alcoholic beverage as this will aggravate rather than improve the situation. Rub the temples lightly for 15 seconds with the eyes open and for 15 seconds with the eyes closed to help the body restore its ability to regulate its temperature.

Heat related illness and death are preventable. This is best accomplished by proactively providing water and minerals to compensate for heat-induced losses rather than trying to play “catch-up” once significant dehydration or mineral deficiency is present. To avoid heat-related illness take the following steps:

· Drink enough water to keep the urine pale and require urination at least every 3 hours.

· Provide 1 gram of sodium for every hour working or playing in conditions that cause heavy perspiration (most salt tablets provide 1 gram of sodium).

· Take 200 – 300 mg of elemental magnesium 2 – 3 times daily. (Preparations vary in the amount of magnesium they provide – for example, 250 mg of magnesium aspartate provides 50 mg. of elemental magnesium and 250 mg. of magnesium citrate 40 mg of elemental magnesium.)

· Drink a serving of a mixed mineral solution every 2 – 3 hours. My favorite is Maximum Vitality’s Hi Energy C, which provides small but beneficial amounts of potassium, calcium, magnesium, zinc, vanadium, manganese, chromium, copper, molybdenum, and sodium.

Taking those measures should not only enable you to survive weather’s deadliest threat, but allow you to continue to work productively and pursue recreational activities you enjoy through the hottest days of the year.

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