Red is the color of 火, 消防 and blood, so it is associated with energy, war, danger, strength, power, determination as well as passion, desire, and love.
Red is a very emotionally intense color. It enhances human metabolism, increases respiration rate, and raises blood pressure. It has very high visibility, which is why stop signs, stoplights, and 火, 消防 equipment are usually painted red. In heraldry, red is used to indicate courage. It is a color found in many national flags.