The recent heat sent many of us reaching for the sunscreen. But now, some experts are warning this may not protect us against a potentially harmful sunray: infrared.
Conventional sunscreens are designed to block out ultraviolet light - UVA and UVB - the rays that damage and burn the skin. However, these products do not block out infrared rays. These rays, which were discovered in 1800, transmit heat, raise skin temperature and are responsible for the warmth you feel when sitting in the sun.
Infrared rays make up to half of the sun's energy (UVA and UVB combined make up between 5 per cent and 7 per cent) and one type in particular, infrared A, can penetrate the deepest layers of the skin - deeper than ultraviolet.
Recent research in animals has suggested infrared A may play a role in skin cancer when combined with exposure to UVB. Infrared A may also contribute to ageing of the skin - scientists suggest it alters some of the biological processes involved in maintaining healthy skin cells, affecting the production of collagen, the protein that acts as scaffolding for the skin. This could ultimately result in wrinkles, sagging and ageing.