Dehydration and Hot Weather can Lead to Changes in the Shape of the Brain

Treating Heat Stroke with Shower Hose

Hot Weather, Heat Waves and Wildfires

Hot weather, heat waves and wildfires are at the top of the news. Many warnings are out there to prevent heat strokes. People are being warned to take steps to avoid becoming dehydrated.

Dehydration without Drinking Water Leads to Changes in the Shape of the Brain

Now a new study published in Physiological Reports, August 22, 2018, by researchers at the Georgia Institute of Technology shows that dehydration without drinking water actually leads to changes in the shape of the brain and some malfunction, as people cannot complete tasks properly and make more mistakes. MRI scans showed that when a person was dehydrated the ventricles in their brains swelled and when they drank water the ventricles contracted. The researchers discovered that heat stress alone can cause these problems, but when accompanied by dehydration the situation is worse.

Monotonous Repetitive Tasks

The 13 participants in the study also had to do monotonous repetitive tasks similar to what might need to be done in industrial situations or in the military. For 20 minutes they had to push a button every time a yellow light appeared on a computer screen. The researchers found that these monotonous tasks can lead to attention lapses, which could potentially lead to accidents. Under the influence of heat and dehydration these were worse.

Overhydration that Leads to Water intoxication (hyponatremia) is a Dangerous Situation

The researchers also discovered that drinking too much water can lead to a dangerous drop in sodium in the blood (hyponatremia). This is why when people are dehydrated, the doctors ask them to slowly sip water rather than gulp it down. It seems the chemistry of the brain that relies on electrolyte balance in the body cannot withstand either extreme of dehydration from too little water or water intoxication from too much water. Blood tests that are used to see if someone is dehydrated are those that measure the electrolytes in the blood, sodium and potassium. A severe drop or severe increase in either of these two electrolytes can upset the chemistry of the brain, but also lead to dangerous, even life-threatening situations.

Dehydration can Lead to Accidents in People Operating Heavy Machinery or Participating in the Military

The results of this study raise some concern about how heat and dehydration can lead to accidents by people who operate heavy machinery, or are driving in the heat, participating in sports or carrying out training in the military.

Other Studies Show that Heat Stress is Especially Dangerous for the Elderly.

Aging leads to an increased sensitivity to heat and a risk to suffer from hyperthermia and all kinds of heat related medical emergencies.

Risks for Hyperthermia in Seniors

  • Seniors tend to take a lot of different kinds of medications and for this reason are even more at risk for suffering from the heat, as some drugs, especially diuretics, blood pressure lowering drugs, sedatives, tranquilizers and more can lead to dehydration.
  • Age-related changes to the skin such as poor blood circulation and inefficient sweat production
  • Chronic heart, lung and kidney diseases
  • Being substantially overweight or underweight
  • Seniors often urinate a lot, and the amount of water leaving the body from perspiration and excessive urination will sometimes be more than the amount of water being drunk.


  • Signs of Dehydration can be dizziness, ringing in the ears, vision problems and mental confusion. If dehydration is not treated it can lead to heat stroke.
  • Alcohol use can lead to very sudden dehydration when out in the sun and heat.
  • Even though your doctor may have put you on a salt restricted diet to treat high blood pressure, high temperatures can actually increase your need for salt. You may have to eat salty foods like potato chips to avoid getting dehydrated. You may even need salt pills if you have to spend a lot of time outdoors, but you must ask your doctor if you need to take more salt.

Heat Related Illnesses

  • Heat Stress
  • Heat Exhaustion
  • Heat Cramps
  • Heat Syncope

Heat Stroke

Heat Stroke is a life-threatening medical emergency that can come on very suddenly without any warning. Anyone who collapses from the heat may be suffering from heat stroke. Phone 911 for help and take immediate steps to bring down their body temperature, which is usually around 104. Hose them off with cold water. If the person is conscious they must be given water to sip, but very slowly. It is good to also offer some high potassium fruit juice like pure orange juice. They must also have something salty to eat or drink.

Rehydration Powders and Drinks

Pharmacies sell over-the-counter rehydration powders and drinks and everyone who spends time outdoors in the heat should carry these with them.


Everyone young or old can get dehydrated very quickly in hot weather. Drinking water is not always effective at preventing dehydration. Everyone should learn how to treat heat stroke.



Leave a Comment