People who suffer from insomnia may have an increased risk of heart failure, according to the largest study ever to investigate the link.
Those who experience all three major symptoms -- trouble falling asleep, problems staying asleep, and not waking up feeling refreshed in the morning -- were more than three times more likely to develop heart failure compared with those with no insomnia symptoms, according to a study of 54,279 people for an average of more than 11 years. The study, funded by the Nord-Troendelag Health Trust in Norway, was published today in the European Heart Journal.
Further research is needed to establish whether insomnia causes the condition, according to the study authors. One possible explanation could be that insomnia activates stress responses in the body that may harm heart function, they said. Heart failure is a condition in which the organ is unable to pump enough blood around the body at the right pressure.
“We do not know whether heart failure is really caused by insomnia, but if it is, insomnia is a potentially treatable condition,” Lars Laugsand, a post-doctoral fellow in the Norwegian University of Science and Technology’s department of public health, and a study author, said in a statement.
Insomnia is associated with an unhealthy lifestyle, including a high prevalence of obesity and lack of physical activity. Treatments include following recommendations on sleeping habits and psychological and drug therapies, he said.
The results were adjusted for possibly confounding factors such as diabetes, cholesterol, physical activity and smoking. When the researchers adjusted their findings to include anxiety, the risk was even higher, with a slightly more than four-fold risk of heart failure.
The fact that the link was found to be largely independent of established cardiovascular risk factors and psychosocial distress supports the possibility that insomnia may play a causal role, the researchers said.
A moderate risk increase related to individual insomnia symptoms suggests that compromising some aspects of sleep can be made up with others. For example, having trouble falling asleep may be compensated for by deep sleep with good continuity, the researchers said.
“Studies like this raise interesting suggestions that need further work to examine,” said Tim Chico, honorary consultant cardiologist at the University of Sheffield in England. “Luckily, many of the things that reduce the chance of heart failure also reduce insomnia: good diet, exercise, weight loss and not smoking.”