According to a specialist journal’s reporting on Wednesday, heart attacks occurring in the morning are severe than those occurring at any other time of the day.

Spanish researchers analyzed data from 811 patients being admitted to a Madrid clinic with a myocardial infarction between 2003 and 2009. The researchers made use of the levels of enzymes in their blood to compute the level of dead tissues (called infarct). Infarcts occur due to halted blood supply to heart muscles.

In the research, it was found out that people suffering from heart attack between 6:00 am and noon, during change from dusk to dawn, had a 21-percent larger infarct in comparison to patients who suffered attacks between 6:00 pm and midnight.

The study which is published in the British journal Heart is based on early evidences that circadian rhythm manipulates the heart in several ways and these include heart rate, BP, cardiac output and function of cells lining blood vessels.

Among the 811 patients, 269 had suffered from heart attacks from 6:00 am to noon. More than three quarter of patients being admitted to the clinic included men. The age of these patients was about 62 years.

The researchers said that these findings will prove beneficial in assessing the usefulness of drugs used against heart diseases.