Dehydration and stroke risk: Tips to protect your brain in the Texas heat
August 29, 2023
By Chintan Rupareliya, M.D., M.H.A., and Rachel Aubert, D.O.
With summer temperatures averaging triple digits and approaching record highs across the state, Texans are dealing with DFW’s blast furnace the best we can: by blasting the AC, taking trips to the pool, and – most importantly – trying to stay hydrated.
Dehydration is a main culprit in heat-related hospitalizations, causing symptoms such as excessive thirst, dry mouth, lethargy, muscle cramps, and dark-colored urine. Dehydration can affect your brain, too, prompting symptoms such as confusion, headache, lightheadedness, and even syncope (fainting).
Being dehydrated should not be taken lightly or dismissed as just “part of living in Texas during the summer.” Everyone needs to stay hydrated in the heat, particularly people with health conditions that narrow their blood vessels – or those who may not have been diagnosed with vascular diseases yet but are experiencing severe symptoms in the heat. Understanding the warning signs of dehydration and how it can affect the body and brain is a good place to start.
How dehydration affects the brain
Dehydration creates imbalances in the body and brain in several ways:
- You sweat more, losing fluids and electrolytes.
- Blood volume decreases. Your blood consists of cells and fluid (plasma). When the body is short on fluid, it is hard for the brain to maintain adequate volume to supply oxygen and other nutrients. This becomes especially difficult if the blood vessels supplying your brain are narrow.
- Blood pressure declines when the heart has less total blood to pump.
These fluid imbalances can lead to a stroke if certain areas of the brain don’t receive adequate blood flow. Dehydration is common among patients who have strokes and can be associated with worse outcomes.
Getting significantly dehydrated is a health risk for everyone. If you've had a stroke in the past or you have a condition that narrows your blood vessels or complicates blood flow, it’s especially important to stay hydrated.
Talk with your doctor about hydration strategies if you have or may be at risk for a vascular condition, such as:
- Narrowed blood vessels (stenosis): More commonly from atherosclerosis, this condition develops as a result of long-term injury to the blood vessel walls, leading to plaque formation that progressively and irreversibly narrows the space in the vessels where blood flows.
- Diabetes: Uncontrolled blood glucose causes osmotic damage (imbalance of water and electrolytes) to the blood vessels, which makes them stiffen and eventually narrow, reducing blood flow.
- Moyamoya disease and syndrome: This condition causes structural damage to the blood vessel walls and leads to narrowing or blockage of the blood vessels of the brain. This may prompt the brain to grow a new, very small and fragile network of blood vessels in an attempt to bypass the point of narrowing or blockage. These narrowed vessels can predispose an individual to ischemic stroke from reduced blood volume secondary to dehydration.
- Sickle cell: The genetic blood disorder inhibits the ability of red blood cells to carry oxygen to the brain.
Stay hydrated – and BE FAST
In a Texas heatwave, it’s easy to get behind on drinking water. Try to drink at least eight 8-ounce glasses of water a day and start sipping as soon as you wake up. Many fruits and vegetables are 90% water or more, and snacking on healthy, hydrating foods – such as cucumbers, watermelon, and strawberries – is a tasty way to boost hydration.
Try these 25 water-rich foods this summer.
Watch for stroke symptoms by remembering the acronym BE FAST:
- Balance: Is there a sudden loss of balance or coordination?
- Eyes: Is there sudden blurred vision, loss of vision, or double vision? Or sudden, persistent vision trouble in one or both eyes?
- Face: Ask the person to smile. Is one or both sides of the face droopy?
- Arms: Ask the person to raise both arms. Does one side drift downward? Is there weakness or numbness on one side?
- Speech: Does the person have slurred or garbled speech? Can he/she repeat simple phrases?
- Time: Every minute counts – time is brain. Call 911 or go to the closest emergency department at the first sign of symptoms. Every minute of delay reportedly damages ~1.8 million nerve cells irreversibly.
Dehydration is a real risk not only in the height of summer but all year long. Getting enough water should be a priority in your daily routine, especially if you have a vascular condition. Don’t second guess if you notice unusual symptoms in yourself or a loved one – it’s better to get checked than to ignore the warning signs and potentially suffer a preventable stroke.
Call 911 if you have signs of a stroke. To talk with a specialist, call 214-645-8300 or request an appointment online.
