Does stress heighten the risk of long COVID?

Clinical study collects data on stress

In the FWF-funded project “Chronic Stress as a Risk Factor for Long Covid,” Fazekas and his team investigated whether and to what extent stress continues to have an effect in the case of a Covid infection.

“There is ample documentation that chronic stress can negatively affect biological processes in the body,” he explains. This means we are often more susceptible to illness during periods of high stress. “We were interested in whether there is also a long-term effect.”

For the StressLoC study, conducted between February 2023 and February 2024, the team invited nearly 550 adults in Graz with confirmed and symptomatic coronavirus infection to participate via text message. Ultimately, the researchers obtained 288 complete data sets: 211 women and 77 men filled out online questionnaires several times over a period of six months and came to the clinic twice for blood tests and a hair sample.

In addition to general information on age, gender, education, income, living conditions, lifestyle, etc., Fazekas' team also recorded:

• subjective information about their own state of health, such as satisfaction with mental and physical health, sexuality, sleep, or social life
• vaccination status, pre-existing conditions, medications
• highly stressful life events in the previous year
• subjective stress levels in the month prior to the illness using a standardized stress test
• symptoms that only occurred since the onset of COVID-19 and were perceived as stressful (several times over a period of six months)
• the stress hormone cortisol in hair samples.

More unfavorable outcomes after stressful periods

The evaluation showed distinct differences between those who recovered without negative consequences and those who still had symptoms after one month. More than 70 percent of the study participants, a total of 210 people, suffered from this early form of long COVID (see NICE guidelines in the box). Unpublished data also show that almost half of this group had developed long COVID two months later, i.e., three months after diagnosis.

“Among those who reported being highly stressed before their illness in the initial survey, the likelihood of persistent symptoms was significantly higher,” notes Fazekas. The feeling of having to master everyday life without social support, a low income, and quite generally greater insecurity and anxiety also increased susceptibility to long COVID, as did the number of pre-existing health problems.

Risk factor: preload

The totality of such pre-existing conditions, especially if the strain persists over a longer period of time, can impair a person's health to such an extent that the body is less able to cope with the infection and its consequences. One such biological consequence is the weakening of the immune or nervous system.

In a publication on the study, the team refers to the “pre-load hypothesis” – once again pointing out the multifactorial nature of Long Covid: A preload or basic preload consists of the interaction of many small or large individual stresses and strains: they may be biological, such as pre-existing conditions or an unhealthy lifestyle; social, such as exclusion, family problems, lack of support from others, or financial problems; and, finally, a person's individual state of mind.

Biopsychosocial medicine is not only interested in risk factors. “We always want to know what protects us against disease.” A doctoral student analyzed the data against the backdrop of this question. “The paper has not yet been published, but we can already state that good social support can protect against Long Covid.”

Biomarkers are meaningless – unlike self-observation

“It is interesting to note that the subjectively reported stress levels were not reflected in the hair samples,” reports Fazekas. Other studies have also shown this. “Once again we see that Long Covid cannot be detected using biomarkers.”

Self-observation, on the other hand, is a good predictor of possible disease progression, notes the researcher. This is also conducive to deriving recommendations for action. “Individuals who feel stressed all along, who tend to be anxious or worried, who have many pre-existing conditions, should absolutely seek support so that a severe infection can heal properly,” Fazekas urges.

So one should not believe that everything will go back to the way it was before one contracted SARS-CoV-2, whether in sports, everyday life, or mental activities. This is especially true for those who still have symptoms several weeks after their infection. “These are harbingers of possible long COVID. They are warning signs to slow down and not overexert yourself,” notes Fazekas. Because “once long COVID has you in its grip, it is difficult to recover from it.”

Policy-makers should also become active in this context, says Fazekas. On the one hand, they need to implement awareness-raising measures that show that we can have an influence not only on our blood pressure, but also on infectious diseases and their consequences. On the other hand, they are called upon to set up the urgently needed multidisciplinary centers where those affected can receive professional support.