There’s a definite science behind why it’s hard to sleep on a hot night. Lying awake tossing and turning on a warm summer evening in your caravan or motorhome is a common experience that Dan Ford, founder of The Better Sleep Clinic, has managed to avoid. Below he shares his knowledge on the issue.
Even though we have a caravan, I still prefer to pitch a small tent and sleep there. As a kid my family went camping most summers, plus I spent time in the NZ Army, so I’ve plenty of good memories sleeping in a tent.
It also helps that a tent can be cooled more easily, because struggling to sleep in the summer heat is more than just feeling hot and uncomfortable; it’s a fundamental conflict between the environment and our biology.
There’s a non-negotiable link between your body’s sleep systems and its temperature control systems. To successfully fall asleep, your body must lower its core temperature. When your warm camper gets in the way of this process, it becomes much harder to sleep.
So, what’s actually going on with heat and sleep? And more importantly, what can you do about it?
The body’s built-in temperature control
Every evening, your core body temperature naturally drops by about 0.5-1°C, reaching its lowest point in the early morning hours.
This slight cooling is one of the main physical signals that tells your brain it’s time to wind down for sleep. In fact, your usual bedtime aligns perfectly with the moment your core temperature is falling at its fastest rate, which helps you fall asleep more quickly.
And what controls this nightly cooldown?
Introducing your brain’s master clock
Your body’s cool-down schedule is managed by your body’s master circadian clock, the suprachiasmatic nucleus (SCN), a tiny cluster of nerve cells in your brain. The SCN is in charge of all your body’s 24-hour cycles, and one of its most critical jobs is managing the rhythm of your core body temperature.
Each evening, the SCN detects the fading light and sends out a pre-programmed signal to begin shedding heat via its chemical messenger: melatonin.
Melatonin causes the blood vessels in your hands and feet to widen, a process called vasodilation.
This allows your circulatory system to pump warm blood from your core to the skin’s surface, where the heat can escape into the cooler air. Your hands and feet are great at releasing heat because they have lots of blood vessels close to the skin.
Why a Hot RV blocks your cooling system (and your sleep)
This entire process relies on a simple principle of physics: heat moves from a warmer object to a cooler one. Your body needs the surrounding air to be cooler than your skin to release its internal heat effectively.
If the air in your caravan or motorhome is too warm, there isn’t enough of a temperature difference. Your body simply cannot get rid of its heat. Your core temperature remains high, the “go to sleep” signal is weakened, and you lie awake feeling stuck.
Practical tips for cool RV sleeping
Understanding the science allows you to take targeted steps. Here’s how to create a better sleep environment on your summer travels:
Ventilation is key. Create a cross-breeze by opening windows and roof vents. Even a small amount of airflow can help your body release heat. Consider a small, battery-operated fan to keep the air moving.
Take a warm shower before bed. It might sound counterintuitive, but a warm shower an hour or two before bed draws heat from your core to your skin. When you get out, the rapid evaporation of water from your skin causes your core temperature to drop, mimicking the body’s natural cool-down signal.
Choose breathable bedding. Use sheets and pajamas made from natural fibers like cotton, linen, or bamboo. These materials allow air to circulate and wick moisture away. Synthetic fibers like polyester will trap heat.
Uncover your radiators. Remember your hands and feet are your primary heat-release zones. Leaving them outside the covers can act as a personal thermostat, helping your body regulate its temperature all night long.
Park strategically. If possible, park in a spot that will be shaded from the hot afternoon sun. Using reflective window covers during the day can also prevent your van from heating up like an oven.
Create a DIY air conditioner. For a low-tech solution, place a bowl of ice or a frozen water bottle in front of your fan. The air blowing over the ice will create a cooling mist.
A cool environment isn’t a luxury for good sleep – it’s a biological necessity. By understanding why your body struggles in the heat, you can take these simple, effective steps to ensure you get the restorative rest you need to enjoy your summer adventures.
Dan Ford is a sleep psychologist at The Better Sleep Clinic, a specialist insomnia clinic. A New Zealand online sleep clinic, The Better Sleep Clinic provides assessment and treatment of insomnia, as well as circadian rhythm disorders, parasomnias, non-respiratory sleep disorders and mental health conditions. thebettersleepclinic.com
