Premature Aging Takes the Heat with Infrared

Excessive exposure to sunlight ages skin prematurely. Although researchers have attributed the harm primarily to UVA and UVB radiation, sunlight includes wavelengths outside the UV spectrum. In fact, approximately 30% of all solar energy that reaches the earth’s surface lies within the infrared A (IRA) range (760–1440 nm). To determine whether infrared A contributes to photoaging, investigators exposed 23 volunteers to 360 or 720 …