Women are more likely than men to suffer sudden cardiac death (SCD) during nighttime hours, according to a study published online in Heart Rhythm.

A study presented remotely from the ACC.20/World Congress of Cardiology meeting suggests that getting either too little sleep or too much sleep are both bad for your heart health.

Looking at the Corintha study, a cross-sectional epidemiological study of 2,043 individuals from the Corinth region of Greece. The researchers for this analysis used ultrasonography to measure intimal media thickness (IMT); mean IMT (mIMT) was set as representative of carotid atherosclerotic burden (atherosclerotic plaque was defined as IMT thickness >1.5 mm or protrusion >50% compared to adjacent segments. The team used surveys to capture data about  sleep duration, which was categorized as normal (six to eight hours), long (more than eight hours), or short (less than six hours). Participants ranged in age from 40 to 98 years (mean age, 64 years).

According to the study  results, those with normal sleep duration had a lower prevalence of diabetes (P=0.001), but no other reductions in risk factors were noted. There were also reductions in mINT and carotid atherosclerotic plaque) in the normal sleep duration cohort. Following adjustment for confounders, analysis showed that those with shorter sleep duration (54%) and also longer sleep duration (39%) had increased odds of carotid atheromatic plaque than those with normal sleep duration.

“We don’t fully understand the relationship between sleep and cardiovascular health. It could be that sympathetic nervous system withdrawal or a slowing[of this system]that occurs during sleep may act as a recovery phase for [usual]vascular and cardiac strain,” Evangelos Oikonomou, MD, lead author and consultant cardiologist, said in a press release. “Moreover,short sleep duration may be associated with increased cardiovascular risk factors—for example,unhealthy diet, stress, being overweight or greater alcohol consumption—whereas longer sleep duration may be associated with a less active lifestyle pattern and lower physical activity.”

He added: “The message, based on our findings, is ‘sleep well, but not too well.'”