July 19, 2023

How to stay hydrated during a heatwave

Our resident dietitian, Olivia Morrison, unpacks the unlikely symptoms of dehydration and how to avoid it happening in the first place.

If you’re in Europe right now, you might be in the middle of a major heatwave, and with our hometown being the land down under, we can speak from experience on recognising the symptoms and more importantly, avoiding dehydration.

Dehydration & heat stress

Dehydration is more dangerous than people realise, especially in heatwaves. It can take as little as 30 minutes for heat to cause dehydration and can be fatal within 1-3 days in hot weather conditions.

Heatwaves are particularly dangerous for elderly people, babies and young children, or anyone with chronic illnesses like; diabetes, blood pressure issues, conditions that affect the brain.

Most people experience ‘heat stress’ without even knowing it, it really doesn’t take a lot. Signs and symptoms can include; thirst, dry mouth, lips and tongue, dizziness, headaches, dark urine and urinating less often than usual, nausea, profuse sweating and muscle cramps.

Symptoms of heat stress can quickly progress in severity, if you start to experience any of the following symptoms please seek urgent medical attention…

  • Fast breathing and heart rate.
  • If you have stopped sweating.
  • Dry, hot and red skin.
  • Not being able to urinate.
  • Vomiting.
  • Irritability, confusion and/or drowsiness.

What to drink during a heat wave

I highly recommend avoiding alcohol in heatwaves. Alcohol is a diuretic, meaning it removes fluids from the body. Although a cold beer sounds refreshing on a hot day it’s very important to avoid it as alcohol is incredibly dehydrating with overconsumption significantly increasing your chance of experiencing dangerous health issues from fluid loss.

Although it’s a myth that coffee and tea dehydrate you, I still recommend avoiding caffeinated beverages in heatwaves. This is because caffeine increases blood pressure which can increase sweating, therefore increasing your risk of becoming dehydrated and feeling faint or light headed in hot weather conditions.

  • TOP TIP* Try to drink more water earlier in the day, rather than waiting for thirst. If you’re relying on thirst as your cue to drink, you’re already dehydrated.

Although water is the ideal beverage of choice, other hydrating drinks like smoothies, fresh juices, milk, cordial, electrolyte tablets like hydrolyte, or even including hydrating foods (yoghurt, watermelon, icy poles, jelly, salad veggies) are great ways to keep yourself hydrated in hot weather!

How much should I be drinking?

As a general rule of thumb; fluid recommendations to prevent dehydration in extremely hot weather is 2.5-3.5L per day for adults and 1-2L per day for children. The best way to do this is by drinking a small glass of water every 20 minutes; this helps prevent you overloading your body with water too quickly.