The daily fear of COVID is history for most of us, but for some the agony lingers. A regular bout of COVID-19 may cause mild symptoms lasting up to two weeks. However, for as many as 40 percent of individuals affected by COVID, at least one symptom will continue for weeks, months, or years. This is known as long COVID. Risk factors for long COVID include having a severe COVID infection, having multiple COVID infections, and not being vaccinated. People at highest risk are those who also have pre-existing conditions. A new study suggests that these people can lower their risk of long COVID by getting six to nine hours of sleep per night.

The study, from researchers at the University of Toronto, is published in the American Academy of Sleep Medicine’s Journal of Clinical Sleep Medicine. The study was produced from data available in the 2021 International COVID Sleep Study II. This study surveyed over 13,000 people from 16 counties and included reported data on COVID infections, pre-existing conditions, long COVID symptoms, and sleep habits.

What Is Long COVID?

According to the World Health Organization, long COVID can be defined as the continuation or development of new symptoms three months after the initial SARS-CoV-2 infection, with these symptoms lasting for at least two months with no other explanation. Common long COVID symptoms may include fatigue, fever, brain fog, shortness of breath, cough, headache, palpitations, depression, and anxiety. Long COVID also causes sleep disturbances that may include poor sleep quality, daytime sleepiness, sleep apnea, and insomnia.

Pre-existing conditions that increase the risk of long COVID include being overweight, being female, COPD, fibromyalgia, anxiety, depression, migraine, multiple sclerosis, heart disease, high blood pressure, and diabetes. It is probable that poor sleep is an added risk factor because of the effect that poor sleep has on the body’s immune system. For example, a prior study found that people who had poor sleep (less than six hours per night) in the days before getting a flu shot had about a 50 percent reduction in immune response to the vaccine.

What Causes Long COVID…

Based on prior studies, adequate sleep is needed for proper response of the body’s immune system. Since long COVID may be a failure of the immune system to respond properly to COVID infection, the objective of the study was to find out if sleep times along with pre-existing conditions play a role in the risk of developing long COVID.

About 2,500 people in the study were diagnosed with COVID-19. Sixty-one percent of these people reported at least one symptom of long COVID. These were the key findings…

  • The risk of developing long COVID was almost twice as high (1.8-fold higher) for average-length sleepers (six to nine hours per night) with pre-existing conditions compared with people without pre-existing conditions.
  • The risk of developing long COVID was three times higher for short sleepers (less than six hours) with pre-existing conditions compared with people without pre-existing conditions and average sleep.

The conclusion of the study is that short sleep time increases the risk of long COVID in people already at risk for long COVID due to a pre-existing condition. Along with controlling other risk factors, getting six to nine hours of sleep may help reduce the risk of long COVID for people already at risk. Risk factors that can be changed or managed for any disease or condition are called modifiable risk factors. The researchers suggest that poor sleep is a modifiable risk factor for people at risk for long COVID.

Source: Study titled “Habitual Short Sleepers with Pre-Existing Medical Conditions Are at Higher Risk of Long COVID,” led by researchers at the University of Toronto, published in the Journal of Clinical Sleep Medicine.

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