Researchers at the Medical University in Shenyang, China, have discovered that people with insomnia could be at greater risk of a heart attack and stroke, according to a survey which has been published in the European Journal of Preventive Cardiology.
Sleep is “essential for biological recovery” and human beings spend one third of their lives asleep, says Dr Qiao He, but more and more people these days complain about not getting enough sleep. In fact, according to some statistics, as many as one third of the German population has suffered from insomnia at some time.
Although previous research has shown that a lack of sleep can have negative effects on health, until now attempts to find a relationship between insomnia and heart problems or stroke have not been very consistent.
This latest analysis looked at the link between symptoms of insomnia and the incidence of death from cardiovascular illness (acute myocardial infarction, coronary disease and heart failure), cerebrovascular accidents or a combination of both.
The symptoms of insomnia are difficulty in getting to sleep, staying awake all night, waking up early or sleep which is not refreshing. In total, the researchers analysed 15 studies in which 160,867 people took part. During the different stages of monitoring, which lasted between three and 29.6 years, 11,702 adverse events were registered.
A significant link was noted between difficulty in getting to sleep, staying asleep or non-refreshing sleep and the risk of cardiac illness and cerebrovascular accident, but there appeared to be no link between waking up early and a greater risk of adverse events.
“We found that difficulty in getting to sleep, staying asleep or not feeling refreshed after sleeping is associated with a 27.11 per cent and 18 per cent higher risk of heart attack or stroke respectively,” explain the researchers.
They admit that more research is needed in order to completely understand the underlying mechanisms which explain this risk, although previous studies suggest that insomnia can change the metabolism and endocrine function, increase the activation of the sympathetic nervous system, raise blood pressure and levels of inflammatory and proinflammatory cytokines, which are also cardiovascular and cerebrovascular risk factors.