Light therapy in the sauna uses coloured light to influence mood and promote relaxation. It is also often referred to as "chromotherapy", a compound of the Greek words for colour and healing. The basic idea is that the different colours of the light spectrum have different wavelengths and can thus affect the human psyche and body in specific ways. For example, red light is associated with energy and stimulating blood circulation, while blue light has a calming effect and helps to soothe. Green is used to induce harmony and balance and yellow is used to promote optimism and mental well-being. In practice, this function in the sauna is provided by LED lights, which can either shine one colour or switch seamlessly between different shades. The aim of light therapy is thus to complement and deepen the overall sauna experience by combining the thermal effects of the sauna with the psychological effects of colour.