TheraPur ActiGel Polar 1000 King Size Mattress
The TheraPur ActiGel Polar 1000 Mattress combines a knitted ActiCool cover with cooling ActiGel foam over pocket springs, which means a cooling surface and a medium feel underneath.
- Cooling cover & airflow foam
- Medium feel suits most sleepers
- Fully hypoallergenic finish
£699
Get the lowest price we've found
Save with the previous model
Some retailers still sell the earlier version of this mattress for less than the current model's best price.
TheraPur ActiGel Polar 1000 Mattress
More available sizes
Mattress details
Mattress
TheraPur ActiGel Polar 1000 Mattress
Size
Firmness
Medium
Construction
Foam
Gel
Pocket Spring
Depth (cm)
22
Layers
4
Layer Details
ActiCool knitted cover
A knitted ActiCool cover that is described as instantly cooling, so the surface feels cooler to the touch when you get into bed.
ActiGel foam
A cooling ActiGel foam layer, listed by a retailer as 6cm, that is designed to optimise airflow. That means less heat building up under you as you sleep.
I-Fibre and Platinum 3D
Breathable layers of recyclable I-Fibre and Platinum 3D polyester. They add cushioning while letting air move through the mattress.
Pocket springs
Pocket springs, listed by the brand at 1,000, form the supportive core. TheraPur doesn't publish a spring size.
Layer details from dreams.co.uk product page, November 2026.
Key benefits
- More room each than a UK double: The UK king gives 75cm each for two sharing, which is 7.5cm more per person than the UK double, so elbows and knees meet a little less often.
- Extra length for tall partners: At 200cm long, the UK king is 10cm longer than the UK double, which means a partner near six foot can stretch out without feet hanging off the end.
- Less disturbance on early starts: The 1,000 pocket springs sit in individual pockets, so when one of you gets up hours before the other, the extra width keeps that movement further away.
- Cooler with two bodies in bed: Two people generate more heat, and the ActiCool cover and ActiGel foam are designed for airflow, so the wider surface gives that heat more space to escape.
- Room to prop and shift: During pregnancy, or while recovering from an injury, the UK king's width leaves space for extra pillows without pushing your partner to the edge.
This size suits you if...
You share the bed every night and feel squeezed on a UK double, one of you is close to or over six foot and wants the extra length, or you sleep warm as a couple and want a medium mattress with room to spread out.
Consider another size if...
Your bedroom is smaller than our suggested 2.7m x 2.9m, or you sleep alone. We'd recommend the UK double instead, which needs at least 2.6m x 2.8m.
Similar Mattresses in This Price Range
Did you know? On Mattress Unboxed we have over 1,000 different mattresses to suit all types of sleepers. View all mattresses.
FAQ's
What size bedroom do I need for a UK king TheraPur ActiGel Polar 1000?
We suggest at least 2.7m x 2.9m for the UK king. New build master bedrooms can feel smaller than their floor plans once wardrobes and bedside tables go in, so measure the space you will actually have left before ordering.
How much space does each person get on the UK king?
Two people sharing get 75cm each on the UK king. The UK double gives 67.5cm each, so the UK king adds 7.5cm per person. That difference is most noticeable if one of you sleeps spread out or a dog regularly joins you.
Is the TheraPur ActiGel Polar 1000 UK king long enough for someone over six foot?
The UK king is 200cm long, 10cm longer than the UK double. For a partner approaching or over six foot, that extra length is often the bigger upgrade, because it lets you lie straight without your feet reaching the end of the mattress.
What are the UK king dimensions in feet?
The UK king measures 5ft x 6ft 6in, or 150 x 200cm. The TheraPur ActiGel Polar 1000 is 22cm deep in every size, so check that your fitted sheets have deep enough pockets for a UK king of that depth.
Is the UK king the largest size of the ActiGel Polar 1000?
Yes. TheraPur makes the ActiGel Polar 1000 in a UK single, UK double and UK king, so the UK king is the biggest option. If you were hoping for a UK super king, this mattress isn't made in that size.