Reds are known to actually raise body temperature.
In tests it has been shown that red prompts the heart rate to speed up. This causes adrenalin to be released into the bloodstream, thus increasing body temperature.
It's why many people find a red room somewhat overpowering, unless the red is balanced by a more restful interior design color.
If you want to use a strong version of it, then use it on small areas such as paintwork, or introduce it in a rug or large picture.
You can use red if you want a room to have impact.
It's often used in dining rooms, where you're normally busy eating and chatting with other family members or friends. When you're concentrating on another activity you aren't too aware of the surrounding decor.
Or use it in a cloakroom or hallway, somewhere you visit briefly.
It usually comes into its own when used as an accent color in flower arrangements, pictures, pillows and especially area rugs.
(Because it is stimulating, red is often used in restaurants. The theory is that it stimulates conversation, which stimulates eating and drinking, which results in people spending more than they intended!)
There's an easy way to make sure the paint colors you select will look great in your home. Sometimes you find you run out of ideas, and when you do see something you like, you're not sure it will work in your situation.
Hint: if you're using a deep red paint color on your walls, you may find you need to use more than one coat to get a good finish. Sometimes as many as three or four may be needed.