SATURDAY, July 31 (HealthDay News) -- When the days grow longer in the spring, teens experience hormonal changes that lead to later bedtimes and associated problems, such as lack of sleep and mood changes, researchers have found.

SATURDAY, July 31 (HealthDay News) -- Heat cramps, heat exhaustion and potentially fatal heat stroke are risks when exercising or playing sports during the summer, but they can be prevented by taking a few simple precautions, advises a Medical College of Georgia expert.