 Acute cardiac and vascular events, like heart attack and sudden cardiac death manifest a clear surge in the early morning hours around the time of waking, so that their peak onset is between 6AM and 11AM. The mechanisms are not fully understood, but we had shown that healthy subjects have impaired vascular reactivity in the early morning endothelial dysfunction. This is associated with a decrease in nitric oxide levels a substance that promotes vasodilatation. We also have described that vessel reactivity and the levels of this substance can recover by noon only when people breakfast. 