Even mild cases of COVID can trigger insomnia in most people, a new study reports.

About three out of four people with mild COVID (76%) reported experiencing insomnia following their illness.

Further, nearly one in four (23%) said they’d experienced severe insomnia, according to results published Feb. 5 in the journal Frontiers in Public Health.

“If you experience insomnia after COVID-19, don’t think that is normal,” said lead researcher Huong Hoang, head of the surgical nursing unit at Phenikaa University in Vietnam.

For the study, Hoang and colleagues surveyed more than 1,000 adults who’d been diagnosed with COVID but did not require hospitalization. The surveys were conducted between June and September 2022.

Half of the participants said they woke more often in the night. A third said they found it harder to fall asleep, had worse sleep and slept for less time.

The severity of COVID infection did not seem linked with the severity of insomnia, researchers noted. Although COVID patients without symptoms scored lower on an insomnia index, the difference was not statistically significant.

There were two groups of patients who did appear more likely to have insomnia following COVID — people with a preexisting chronic condition and people who scored highly for symptoms of depression or anxiety.

Both of those groups had a higher rate of insomnia than the rest of the COVID patients, researchers said.

However, the link between those two groups and insomnia can run in either direction, researchers noted. Insomnia can cause worse mental and physical health, but it also can be exacerbated by poor mental and physical health.

“Since this is a cross-sectional study, the relationship of anxiety and depression with insomnia cannot be fully investigated,” Hoang said in a journal news release.

Hoang offered some advice to COVID patients experiencing sleep problems.

“If insomnia does not bother you much, you can take some simple actions, such as: taking a warm shower before bedtime, shutting your phone down at least one hour before going to bed, doing 30 minutes of exercise per day, and avoiding caffeine after 4 p.m.,” Hoang said.

"In case insomnia really troubles you, you can try some over-the-counter sleep aids,” Hoang added. “If they don’t help, go to see a sleep therapist.”