People who work in shifts are somewhat more likely to suffer a heart attack or stroke than their counterparts who work only in day, a new study revealed.

In an analysis of 34 studies, a team of researchers from Canada and Norway found shift work can upset the body clock and put an adverse effect on the functioning of heart.

They studied a total of 17,359 coronary events, including cardiac arrests. Of the total cases, 6,598 were heart attacks and 1,854 were strokes caused by lack of blood to the brain.

Researchers concluded that these events were more common in people who worked in shifts than in other people.

The study published in the British Medical Journal, estimated that that shift workers were 23 per cent increased risk of heart attack, 5 per cent increased risk of stroke, and 24 per cent increased risk of coronary event.

Researchers also concluded that limiting night shifts could help workers cope with higher risk of heart attacks and strokes.

Previous studies had linked shift work to an increased risk of diabetes and high blood pressure.