Summer Heat: Preventing and Recognising Dehydration in Babies

Introduction:

Finally, the warm weather is here again! Along with the sunshine, however, come a unique set of challenges for our youngest family members. If this is your first summer with your little one, you might be feeling a bit anxious about keeping them hydrated and recognising the signs of dehydration. In this post, we’ll explore why babies are more vulnerable to dehydration, the warning signs to look out for, when to seek medical attention, and, most importantly, practical tips to help prevent dehydration altogether.

Let’s get straight to the point: babies, especially those under 12 months, are more vulnerable to dehydration compared to older kids and adults.

Why Are Babies at Increased Risk?

💦 Higher Body Water Content:
Babies have a higher body water content, meaning their bodies are made up of approximately 75-80% water (and even more if they are premature), compared to adults, where our water content is about 60%. This means babies have more fluid to lose and can become dehydrated more quickly if their reserves aren’t replenished.

🌡 Immature Thermoregulation:
Babies can’t regulate their body temperature as effectively as older children and adults. They can overheat more quickly without sweating efficiently, which increases the risk of dehydration and heat-related stress. In fact, their bodies heat up to five times faster than an adult's under the same conditions!

🔥 Higher Metabolic Rate:
Babies have a higher metabolic rate, so they generate more heat and lose fluids more quickly—even without sweating much. Their little bodies are also working hard to grow and develop, leading to increased water requirements.

🚰 Rapid Fluid Loss:
Although babies sweat less, they can still lose fluids through other means, such as breathing, urine, and bowel movements.

👶 Limited Communication:
Lastly, babies aren’t able to communicate their needs as clearly as older kids or adults. While we can simply say, “I’m thirsty,” babies can only cry, leaving us to guess what’s wrong (sound familiar?). This can sometimes delay their fluid intake during warm weather. Similarly, if they’re feeling too hot because they’re wearing an extra layer, they can’t take it off or tell us they’re uncomfortable. Instead, they’ll fuss or cry, relying on us to figure it out.

Common Causes of Heat-Related Dehydration in Babies 

🥵 High Temperatures & Lack of Ventilation:
Exposure to hot or humid environments increases fluid loss. That amazing black pram you got on sale? Well, it’s absorbing heat like nobody’s business. Combined with a blanket thrown over the hood to block the sun, this creates a lack of airflow or ventilation, leaving your baby overheated. Hot weather increases water loss through both sweating and breathing, even though babies sweat less than older children or adults. Additionally, high humidity can make it harder for their bodies to cool down effectively, raising the risk of overheating and dehydration.

🥵 Lack of Extra Feeds:
Babies under six months are entirely dependent on bottle-feeding or breastfeeding. If feeds aren’t increased during hot weather, they might not get enough fluids and start to dehydrate. And if you’re breastfeeding, don’t forget to drink extra yourself on hot days to help compensate for your baby’s increased feeds.

🥵 Illness:
Even mild illnesses, with a slight fever or congestion, can increase fluid loss and the risk of dehydration, especially when combined with hot weather. To make matters worse, babies might also refuse to feed as much when they’re unwell, compounding the issue.

🥵 Overheating:
Overdressing a baby in heavy clothing or wraps, or swaddling them too tightly, can trap heat and increase their body temperature, leading to fluid loss. Although they may look cute, perhaps save the Christmas reindeer outfit for a different day if the thermometer is high on Christmas Day!

Signs of Dehydration

Mild Dehydration:

❌ Fewer wet nappies or nappies that feel less “full” than usual.

❌ Dry lips.

❌ There may not be many other specific signs at this stage.

Severe Dehydration:

❌ Sunken eyes.

❌ Cool hands and feet.

❌ Few or no tears when crying.

❌ Rapid breathing or a fast heart rate.

❌ Sunken fontanelle (soft spot on the head- see picture below).

❌ Lethargy or extreme fatigue—your baby may seem very tired, less responsive, or difficult to wake.

When to Get Help

👩‍⚕️If your baby is under six months old or has a chronic (long-term) illness, they should always be seen by a doctor—even for mild dehydration.

🚑 For a baby of any age showing signs of severe dehydration, call an ambulance or head straight to the nearest hospital emergency department.

Preventing Dehydration

✅ Offer More Frequent Feeds:
During hot days, it’s essential to offer the breast or bottle more often. If your baby is over six months and has started solids, you can also offer small amounts of cooled, boiled water between feeds to help keep them hydrated.

✅ Monitor Clothing Choices:
Dress your baby in lightweight, loose-fitting, and breathable fabrics. 

✅ Create a Cool Environment:
Use fans, air conditioning, and shaded areas to ensure a comfortable temperature. For outdoor activities, stay in the shade and limit exposure during peak heat hours.

✅ Regular Nappy Checks:
Keep track of how many wet nappies your baby produces. A sudden drop in wet nappies is a key indicator of dehydration.

✅ Avoid Unnecessary Exertion:
Limit activities that might make your baby overly restless or sweaty during heat waves, especially if outside. Instead, consider indoor play or tummy time in a cool area. "Story-Time" at the library and indoor air-conditioned playgroups at our local community centre has kept my sanity over the years during the hot weather (and rainy days!). 

Summary

By understanding why babies are more vulnerable to dehydration, recognising the warning signs, and taking proactive steps to keep them cool and hydrated, you can ensure your little one stays safe and comfortable during the warmer months. Remember, prevention is key, and if you’re ever unsure or concerned about your baby’s hydration levels, don’t hesitate to seek medical advice. Let’s enjoy the sunshine while keeping our youngest family members healthy and happy!