According to a study in HeartRhythm, women were more likely to experience sudden cardiac death (SCD) at night compared to men. Overall, men are about twice as likely to experience SCD at any time. In sudden cardiac arrest, the heart stops beating due to an electrical problem, such as an irregular heart rhythm, as opposed to a blocked artery. The survival rate for out-of-hospital cardiac arrests in the U.S. is around 10%.
While less common, nighttime incidents of sudden cardiac arrest can be harder to identify and respond to since adults may be sleeping. In a study of 4,126 adults who died from sudden cardiac arrest, most incidents, 3,208, occurred during the day. Of the 918 incidents of SCD that occurred at night (between 10 p.m. and 6 a.m.), more incidents occurred in women. Compared to one in five men, one in four women experienced SCD at night. Adults who experienced SCD at night were also more likely to have chronic obstructive pulmonary disease (COPD) or asthma and use medications that affect the central nervous system. These included antidepressants, tranquilizers, and sedatives.
The authors note further research is necessary to expand on these findings. For now, they note clinicians can keep these results in mind when prescribing medications that may limit respiratory function to patients at risk for SCD, especially women. The study was funded by the NHLBI.