How to Beat the Heat: Focus on Fluids

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Did you know that the elderly population is one of the most vulnerable segments to heat related illnesses? Chronic disease, some medications, and poor physical conditioning can decrease the body’s ability to rid excess heat from the body. There are four processes by which the body can dissipate heat: conduction, convection, radiation and evaporation.

  • Conduction– occurs when the body comes into contact with a cold object and transfers the heat to that cold object, just like applying cold packs to the body.
  • Convection– happens when cool air passes over the body and lifts the heat away, like on a windy day or with use of a fan.
  • Radiation– is when heat is released by the body into the environment.
  • Evaporation– is how the body uses sweat and is the major way that the body dissipates heat when the temperature is above 68’F.

Cooling the body through the means of evaporation requires one to be fully hydrated. This can be somewhat of a problem for seniors because as one ages the thirst mechanism becomes less reliable. Also, some medications can cause dehydration and may require additional fluids to maintain adequate fluid balance. Seniors should take preventive measures with regards to hydration. Requirements for hydration can vary according to current health status, medication use, and current weight. A general rule of thumb is:

  • Women over 60-drink 1500ml or 6-7 cups of fluid per day
  • Men over 60-drink 2000 ml or 8-9 cups of fluid per day

Not all fluids are created equal and some can actually have a dehydrating effect. Fluids containing caffeine and alcoholic beverages should be avoided especially when trying to hydrate the body during the hot summer months.

Examples of good summer hydrating fluids:

  • Ice Water
  • Ice Water with freshly squeezed fruit
  • Decaf Ice Tea or Ice Coffee Lemonade
  • Decaf Diet Soda Water
  • Fruit Slushies
  • Popsicles
  • Milk
  • Sport Drinks

There are numerous signs and symptoms to indicate fluid intake is not sufficient. If any of the below signs occur immediately drink some cool water or other fluid.

  • Low Urine Output
  • Dry Mouth
  • Dizziness/Lightheaded
  • Dark Urine Color
  • Not Sweating
  • Fatigue
  • Nausea
  • Hot/Face flushed
  • Confusion
  • Headache
  • Muscle Cramps or Weakness Fast Heartbeat
  • Worried Feeling/Anxiety

If the condition should worsen immediate medical attention should be sought.

Note: Drinking fluids should occur during and in between meal times. 

Information from: Heat Exhaustion and Heatstroke,; Hydration and Seniors, Peterborough County-City Health Unit; Evaluation and Treatment of Heat- Related Illnesses, American Family Physician. Nutrition Education for MAY 2006; Republished for JULY 2007. Produced by Meals On Wheels, Inc., of Tarrant County by Sherry Simon, R.D./L.D.

For questions regarding nutrition education contact: Sherry Simon, R.D./L.D., Director of Nutrition Services for Meals On Wheels, Inc. of Tarrant County at 817-336-0912 or email: Website:

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