Nighttime leg activity or restless legs during sleep could be more than just annoying, it could be a sign of something more serious.

Men who jerked and flexed their legs involuntarily at night were more likely to develop cardiovascular disease in a new study of sleep and chronic disease in the 65-and-up crowd.

During a one-night sleep assessment, more than two-thirds of men had the involuntary movements, which usually occur in the foot or at the ankle or hip joint, and most of them woke up during the night because of it.