Sleeping little and badly, stress, anxiety and burnout affect the immune response and increase inflammation. As a result, these conditions can increase the risk of contracting viral infections, including colds, pneumonia but also COVD-19. On the contrary, every extra hour of sleep can reduce the risk of getting sick by 12%. This is what emerges from a recent scientific research performed by a team from the prestigious Johns Hopkins Bloomberg School of Public Health, Baltimore, USA, and published in the British Medical Journal Nutrition, Prevention and Health (Kim et al, BMJ, 2021).
Insomnia and stress increase the risk of viral infection
Previous studies have shown that sleep disturbances but also stress and burnout can increase the risk of contracting viral infections, especially colds and pneumonia. However, no studies so far have established whether this can also apply to the new coronavirus.
COVID 19 and weakened defenses, the experiment
In order to assess how much sleep and anxiety may impact on the natural defenses and on the risk of developing a moderate to severe form of COVID 19 in case of infection, the researchers recruited almost 3000 people, chosen among hospital workers from different countries. All the participants were asked to fill in a questionnaire indicating the hours of sleep per night, any sleep disturbances, the state of agitation and perceived stress, if up to that moment they had had a diagnosis of COVID 19 and, if they had, to indicate symptoms and severity.
An extra hour of sleep is enough…
What emerged, analyzing the data, is that having problems in sleep has led to an 88% increase in the risk of contracting COVID 19 infection. Instead, every hour extra sleep was associated with a 12% reduction in the likelihood of developing COVID-19 infection. Stress, anxiety and exhaustion are associated with more than twice the likelihood of contracting COVID in a severe form.
The link between anxiety, insomnia, inflammation and infection
The possible explanation for the link between anxiety and insomnia and an increased risk of developing a more severe form of COVID 19, as well as other viral infections such as colds and pneumonia, appears to be the increase, in these conditions, of pro-inflammatory substances. These substances weaken the immune system in the long run. In addition, since the most serious forms of the new coronavirus are linked to the cytokine storm, that is, the excessive release of inflammatory cytokines, presenting at the time of infection an already elevated inflammatory state probably increases this risk.