The extent of damage rose as the bedroom grew brighter, according to the study.
Most people who have broken heart syndrome are older than 50, and the condition is more common in women than in men. However, men might be in more danger.
Many experts have questioned the research, saying it's not likely the supplement itself causes a higher risk of heart problems, but rather melatonin might be masking other problems.
Former Vice President Dick Cheney battled heart disease for most of his adult life. He had his first heart attack at the unusually young age of 37.
Heat can trigger heart attacks and strokes. Even daily activities in hot weather can put a strain on all your organs, especially your heart, which has to pump harder to keep your core temperature close to normal.
The American Heart Association and Providence Saint John's Health Center in Santa Monica unveiled a CPR kiosk that teaches proper technique.