Hydration and Heat

It’s not a secret the summers in Arizona are hot. ​On average around 3,000 Arizonans are admitted to the ED each year due to heat related illnesses​. Average summer temperatures in Arizona hover between 90-110+ degrees Fahrenheit. This summer in particular has set a new record of days with temperatures over 110 degrees. Our body’s primary means to manage body temperature, sweating, can get quite the workout with such high temperatures.

Our body is composed of around 65% water, decreasing to 50% as we age. Water is essential for our cellular structure and most bodily functions. Many of our organs carry a high water volume. Water is used for many vital body functions such as flushing waste from our system, transporting nutrients, and regulating body temperature.

Our body helps manage high temperature with multiple processes, one of which is sweating. During perspiration, sweat glands will begin to secrete a fluid composed primarily of water with trace amounts of other chemicals and minerals. This fluid then undergoes evaporation, taking heat away from the body. The hotter you are, the more sweat is produced to evaporate and cool you off.

At rest in a cool environment you can still lose up to a half liter of water per day through this process, often without noticing. In excessive heat this can increase to 1-2 liters ​per hour and beyond.

Dehydration of just 2% can cause mild symptoms of dehydration. As dehydration continues, symptoms intensify and your body’s ability to function will begin to decline. At 5% dehydration grogginess, headaches, and nausea are common. Heart rate and respiration rate will increase to compensate for increased blood viscosity. Symptoms will continue to progress beyond that and become more severe including delirium and loss of consciousness. 10% or greater dehydration often requires hospitalization. Only 15% hydration is often enough to be fatal.

Common symptoms of dehydration:

  • Thirst
  • Dry mouth
  • Dizziness
  • Decreased sweating or dry, cool skin
  • Headache
  • Muscle cramps
  • Dark colored urine
  • Decreased urine frequency or volume

Please note that thirst is not always the first symptom of dehydration, and you can already be dehydrated well before feeling thirsty. Certain neurological conditions, pathologies, or cognitive impairments can also impair your bodily sensations. ​Some stroke survivors report no longer feeling thirst at all due to damage to the hypothalamus​.

Severe dehydration is common in patients with dementia or other cognitive disorders for a variety of reasons. Patients can be lacking in the sensation of thirst due to the disease process, or are no longer able to effectively communicate thirst to caregivers. Short term memory issues can also cause patients to have difficulty tracking proper hydration frequency and volume. Due to altered taste, some patients report no longer liking the taste of water, and will not drink enough. Teas and fresh squeezed fruit can be used to help improve or disguise the taste. Certain brands of freezer pops are specifically designed to combat dehydration and are loaded with electrolytes. Sometimes getting creative is necessary.

Cramping is another common symptom of dehydration. Our nerves work on a very specific balance of electrolytes, essential minerals found within our body fluids. When this balance is off muscles may begin to “misfire”, causing cramping. Common electrolytes include sodium, potassium, and calcium. Electrolytes are found in a varied diet, and can be maintained without any additional supplements. Common sources of electrolytes include: turkey, sweet potatoes, avocados, and other fruits and vegetables.

Sports drinks are high in carbohydrates via simple sugars, and are designed to help an athlete quickly replenish their fuel supply during activity. Unless you are exercising or performing vigorous activity, especially outdoors, sports drinks are no different from drinking a soda due to the sugar content. There are many electrolyte powders available on the market that can be added to water to replenish your supply without the additional sugars and carbs of sports drinks. Electrolytes, however, can be naturally replenished via diet.

Often by the time you begin to feel thirsty you’re already mildly dehydrated. In excessive heat water loss can greatly increase due to increased perspiration. Dehydration can very quickly become serious, and sometimes fatal. Maintaining a steady hydration throughout the day is your best option to prevent this.

The Arizona Department of Health Services suggests consuming at least 3 liters of water per day. Increase this by 1-2 liters per hour during outdoor exposure and activity. While that may seem like a lot, this amount is very manageable if spread over the course of the day. Try and find a drinking schedule that works best for you. Insulated water bottles are reusable and can help keep water at an actually drinkable temperature while out and about.

Water intake in a habit, and like most habits, the hardest part is getting started.