7 Signs That Your Baby is Too Hot While Sleeping: What To Look Out For

Baby sleeping in a Woolino 4 Season® Ultimate Baby Sleep Bag

As a parent, understanding the varying signs that your baby is too hot and knowing how to maintain your baby's temperature for optimal comfort throughout the night is essential. An overly warm baby can become restless, fussy, and is at an increased risk of serious complications such as sudden infant death syndrome (SIDS), heat stroke, and dehydration.

Many parents are taken aback to discover that nighttime overheating poses a significant risk to infants. Unlike adults, babies cannot regulate their temperature as effectively, making this a critical factor when dressing your baby for sleep. It’s paramount to ensure your baby's sleep attire doesn't risk them becoming overheated.

While cute pajamas can be tempting, it's the comfort and safety of your child that should dictate their bedtime attire, not the latest trends. The clothes they wear can greatly impact their sleep quality and safety.

This article aims to illuminate the signs of overheating in babies, and to guide you on how to strike the right balance, ensuring your baby is warm – but not excessively so – throughout the night.

Understanding Baby's Sleep and Body Temperature

Regulating body temperature can be a challenge for anyone, but for babies, it's even more complex. Unlike adults, infants can't adjust their clothing layers when they feel too hot or too cold. This limitation puts them at a heightened risk of overheating - a risk you'll want to mitigate for your baby's health and comfort.

A baby's normal body temperature ranges from 95.8 to 100.3 degrees Fahrenheit (36.7 to 37.9 degrees Celsius). However, if their temperature rises above this range, it can be a sign of overheating. A flushed complexion, rapid breathing, and restlessness can also indicate overheating. More on this later in the article.

Older children and adults have a range of methods to regulate their body temperature. From sweating and shivering to controlling blood vessel dilation and constriction, these mechanisms help maintain a comfortable body temperature most of the time. However, babies don't develop these regulatory abilities until they're several weeks old. Even then, their larger surface area to volume ratio makes them more susceptible to temperature fluctuations than adults.

Blankets, while seemingly a simple solution, can't be safely used for infants under one year old due to the risk of suffocation. Instead, many parents turn to alternatives like swaddle blankets and sleep sacks.

These options provide a combination of warmth and temperature regulation, ensuring your baby stays cozy and safe throughout the night. More on this later in the article.

Baby sitting on lambskin rug and wearing a Woolino merino wool bodysuit in Lilac

The Risks of Overheating in Babies

Overheating is a danger that many parents may underestimate, posing both immediate and long-term risks. In the short term, overheating can cause your baby to become restless and irritable, leading to symptoms such as:

  • Dizziness
  • Confusion
  • Vomiting
  • Lethargy
  • Dehydration
  • Unresponsiveness
  • Rapid heartbeat

In the long term, the implications can be far more serious, potentially even fatal. There is evidence suggesting a correlation between overheating and SIDS (Sudden Infant Death Syndrome), a risk every parent should be acutely aware of.

7 Common Signs Your Baby is Too Hot While Sleeping

So, what are the signs that your baby is too hot while sleeping? There are a few key indicators that you should look out for.

- Checking core body temperature: It's common for a baby's hands and feet to feel cool. Instead of using these as indicators of body temperature, check the baby's core body temperature. You can do this by lightly touching the baby's chest or the back of the neck. If these areas feel excessively warm to the touch, the baby may be overheating.

- Flushed skin: A baby's skin can provide telltale signs that they are too hot. Look for a red, flushed complexion. This happens because the body is trying to cool itself down by bringing blood to the surface of the skin.

- Damp, sweaty hair: Babies, like adults, perspire when they're hot – this might not be the case when they’re only a few weeks old as stated above. If your baby's hair is damp or sweaty, particularly if they haven't been involved in any strenuous activity, this could be a sign they're too warm.

- Lethargy or decreased activity: Although babies can't express confusion or dizziness like adults, they might display signs of being unwell by being less active or lethargic. If your baby is less responsive, seems drowsy, or shows decreased interest in their surroundings, they might be too hot.

- Increased heart rate: An increased heart rate can be a sign of many things in a baby, one of them being overheating. As a parent, it might be difficult to assess this without proper medical training or equipment. However, if you notice that your baby's heartbeat seems more rapid than usual, this could be a potential sign of overheating.

- Fast breathing: When a baby's body is trying to cool down, one of the ways it does this is by increasing the breathing rate. If your baby seems to be breathing more rapidly than usual, especially if they're at rest or sleeping, they might be too hot.

- Unusual behavior or symptoms: While vomiting is not typically associated with overheating, any dramatic change in behavior or sudden onset of symptoms like vomiting should be a cause for concern and prompt a consultation with a medical physician.

Remember, it's important to monitor the room temperature and how your baby is dressed, especially during sleep or in warmer weather.

If your baby shows any signs of overheating, try to cool them down by moving them to a cooler environment, removing layers of clothing, and offering them fluids if they're old enough. Should any severe symptoms appear, such as lethargy, a high temperature of 100.3°F or above, or refusal to drink, seek immediate medical attention.

As always, this advice is meant to be general and may not be accurate for all situations. Always consult with a pediatrician or healthcare provider for personalized medical advice.

Baby sleeping on lambskin rug, wearing a Woolino 4 Season® Ultimate Baby Sleep Bag in Rust

How to Prevent Your Baby From Overheating

Preventing a baby from overheating during the night involves two key elements: environment and clothing


The first key element in preventing overheating is managing the baby's environment. Aim for a room temperature between 68°F and 72°F. In hotter climates, maintaining this can be challenging. However, a temperature up to 75°F can be acceptable, as long as the baby is dressed in lighter clothing and monitored closely.

Consider using a fan to cool the room, ensuring it's directed away from the baby's crib for safety.

Regular monitoring is crucial. Establish a habit of checking your baby's temperature at regular intervals, focusing on their chest to gauge core temperature. This practice will help you to quickly identify any signs of overheating.


The choice of clothing is equally crucial in preventing overheating. Once babies outgrow swaddling, many parents opt for sleep sacks. When selecting a sleep sack, consider its TOG (Thermal Overall Grade) which indicates the level of warmth it provides.

Sleep sacks with temperature-regulating features can be a safer choice for year-round use, reducing the risk of overheating.

The fabric of the sleepwear should also be taken into account. Opt for breathable materials such as cotton sleep sacks or lightweight, natural fabrics like wool.

The choice of clothing should also adapt to the season. During winter, consider adding a couple of light layers under the sleep sack like a bodysuit. In contrast, during summer, a single layer or just a diaper and the sleep sack might suffice.

Sleep sacks provide a range of benefits to parents and babies alike. They’re versatile; they create a micro-environment around your child, preserving body heat and reducing the need for bulky layers that are associated with an increased risk of SIDS.

Even with your baby appropriately dressed, regular temperature monitoring remains essential. It's advisable to check on your baby at frequent intervals, using these opportunities to feel their chest and gauge their core temperature. This habit ensures that any issue can be swiftly identified and addressed, promoting your baby's comfort and safety.

What to Do If Your Baby is Overheating

Understanding how to react if your baby is too hot during sleep is critical. We've established that overheating poses significant dangers, but you also don't want to immerse your baby in cold water to cool them down; this could cause shock.

Instead, if you suspect overheating, gently lift your baby from the bed and remove as many clothing layers as possible. Then, use a slightly damp washcloth to stroke over their skin. The evaporating water will help cool them at a safe and steady rate. The washcloth can also be used to fan them lightly.

If necessary, you can put your baby in a lukewarm bath to gradually reduce their body temperature. Make sure the water isn't cold, as you want to avoid causing a shock that could result from a sudden or extreme temperature change.

Providing a drink of breastmilk or formula can also aid in cooling your child.

If your baby appears lethargic or unresponsive, it’s advisable to contact your pediatrician who will be able to advise on the next steps.


It’s important to pay close attention to your baby’s temperature throughout the night and to think about the best way to dress them to prevent overheating. Overheating can be dangerous if it escalates quickly.

Make sure to look out for the signs that your baby is too hot while sleeping as mentioned above. If you are ever in a position where you are unsure, contact your pediatrician who will be able to advise you as to what you need to do.

Ensuring your little one’s bedroom is properly regulated from a temperature perspective can help to ensure they maintain an acceptable body temperature. Clothing also plays a key role in keeping your baby at the right temperature throughout the night, and having sleepwear that regulates temperature well – like 4-season sleep sacks – can make a huge difference.


What is the optimal room temperature for a baby's sleep?

Experts often suggest maintaining a room temperature between 68 and 72 degrees Fahrenheit for your baby's sleep. Although this might seem a narrow range, it provides the best environment for keeping your baby at an ideal temperature overnight. If needed, a fan can be employed to lower the room temperature; however, it should be directed away from your child.

How does a baby's sleepwear influence their body temperature?

Dressing your baby in multiple warm layers can cause their body temperature to rise. Therefore, it's vital to ensure your child isn't bundled in heavy, thick, or bulky clothing overnight or covered in too many layers. You should also avoid putting a hat on your baby while they sleep, as they release a lot of heat through their heads, which aids in maintaining a comfortable body temperature.

Can I use a sleep sack for my baby in hot weather?

Absolutely! Sleep sacks can still be utilized in hot weather, provided they are lightweight and made from breathable material. If the weather is particularly hot, you might opt to dress your baby in just a diaper underneath the sleep sack. The sleep sack will guard against the chill as temperatures decrease overnight and also provide a sense of security.

How does a temperature-regulating sleep sack, like those offered by Woolino, work?

Wool is renowned for its thermoregulating properties, making it the perfect material for sleep sacks. The magic lies in wool's ability to wick moisture away from the body. This action draws sweat away, leaving the skin dry and promoting cooling. Compared to cotton or synthetic fibers, wool is superior at absorbing moisture, which is why Woolino's sleep sacks help maintain an ideal temperature for babies throughout the year.