Do cooling mattresses actually work? Yes – and Simba makes some of the best

In a world full of sleep hacks and gadgets promising to cool you down at bedtime, it can be hard to know where to start when your sleep takes a turn for the worse. Your mattress is an obvious place to look, but cooling mattresses are often overlooked outside the two or three hottest months of the year.

What many people don't realise is that cooling mattresses can still be beneficial in autumn and winter, as they're designed to regulate temperature rather than simply make your bed feel cold. Your core body temperature needs to drop slightly to help you fall asleep, so a temperature-regulating mattress can help excess body heat escape even when your bedroom is cool.

Simba explored this with its upgraded Hybrid mattress range back in August, introducing new cooling technology designed to help you sleep better in the heat by keeping you up to 4.4°C cooler. A few weeks later, my own mattress arrived, and I got straight to testing it.

I wanted to put this review together after testing the mattress in two very different environments. First, I wanted to see how it performed during the heatwaves we'd experienced over the summer, which I managed to do towards the end of August. Then, as temperatures dropped, I wanted to find out whether the cooling technology would still make a difference, even when the weather turned colder.

I've been testing the upgraded Simba Hybrid Ultra, which earned five stars in our review of the original model. This newer version features graphite-infused HeatRelease strips designed to improve airflow and heat transfer, helping your body stay at a comfortable temperature throughout the night. The technology now comes as standard with the Hybrid Ultra, whilst it's an optional extra for the Hybrid Luxe and Hybrid Pro.

As expected, the technology was a godsend during the summer heatwaves. The mattress felt noticeably cooler as soon as I got into bed, and it stayed that way throughout the night. My partner also noticed the difference, and even though our super king means we rarely feel the heat coming off one another anyways, the cooling effect was still clear. Neither of us even kicked off the duvet during the night, which is usually a telltale sign in itself.

I was also sleeping on Simba's new Cool Linen bedding, which I know helped as well. You can read more about my experience with that in my separate review.

However, it wasn't until temperatures started to drop that I really appreciated the difference the cooling mattress could make, and I've been experiencing some of the most restorative sleep I've had in a long time.

The cooling effect isn't as obvious when I first climb into bed now, but I no longer overheat once I'm under the covers. That seems to be helping me stay asleep for longer and enjoy deeper rest, and my Oura Ring appears to be showing the results. I've included a few examples from the past few weeks below:

I'd never considered buying a cooling mattress before, as I assumed it was only worth having during the summer. After all, why invest in something if you can only enjoy its benefits for a few months of the year? However, sleeping on the Simba Hybrid Ultra with HeatRelease technology has completely changed my mind, and I think it could change yours too.