The many health benefits of sleep are well documented, but less is known about how some of its specific aspects – such as duration, insomnia, and daytime sleepiness – could influence the risk of disease.
This is what researchers at France’s National Institute of Health and Medical Research (Inserm) set out to investigate. Their recently published findings suggest that improving sleep could help limit the onset of cardiovascular pathologies.
Potentially affecting stress, mood, weight gain, anxiety, concentration, memory and the immune system, insufficient sleep can impact many aspects of health. This has led to the proliferation of tips and advice of all kinds – including how hitting the “snooze” button could be good for you – to help people fall asleep more quickly and easily, and get the amount of rest they need.
While it’s already known that certain sleep disorders can have a considerable impact on health, a team of Inserm researchers, in collaboration with the Centre Hospitalier Universitaire Vaudois in Lausanne, Switzerland, set out to investigate a potential association between five aspects of sleep and cardiovascular risk.
Published in the European Heart Journal, their research was based on two surveys, one of 10,157 adults aged 50 to 75 in Paris, the other of 6,733 adults aged over 35 in Lausanne.
To examine a potential association between sleep disorders and cardiovascular risk, the researchers asked all participants to complete a specific questionnaire, previously “validated by the scientific community”.
The questionnaire took into account the following aspects of participants’ sleep: duration of sleep each night, whether they were morning or evening people, frequency of insomnia, frequency of excessive daytime sleepiness, and sleep apnoea.
Calculated at the start of the research and again between two and five years later, the score ranged from 0-5, from the worst-possible result to optimal. The latter represented seven to eight hours of sleep per night, no insomnia, no apnoea, no excessive daytime sleepiness, and being a morning person.
The researchers also monitored the occurrence of cardiovascular events for eight to 10 years.
The experts were thus able to draw two major conclusions from their findings. Firstly, they suggest that the higher the score at the start of the study, the lower the risk of experiencing a cardiovascular event.
In detail, they observed that the risk of developing such pathologies fell by 10% for adults who obtained a score of 2 compared with those who had a score of 0-1; then by 19% for participants with a score of 3; by 38% for a score of 4; and finally by 63% for the optimal score of 5.
In short, they observed a significant reduction in cardiovascular risk when people benefit from quality sleep, and in sufficient quantity.
“Nearly 60% of cardiovascular events could potentially be prevented if all individuals had an optimal sleep score, highlighting the potential public health implications of the results,” explained Inserm research director Jean-Philippe Empana, who led the study.
The researchers were also able to examine the evolution of this score over several years, revealing that it did not change, either positively or negatively, for the majority of participants. On the other hand, the score worsened in 11% of adults, and improved in 8%.
In conclusion, the risk of developing one or more cardiovascular pathologies fell by 16% for each point gained over the follow-up period, regardless of the aspect of sleep that improved the score.
“Our study shows that five aspects of sleep carry an almost equal weight in the association with the risk of coronary heart disease and stroke, and that improving one of them over time can lead to a significant benefit,” the researchers concluded.