Insomnia and anxiety may be associated with a reduced number of key immune cells, potentially weakening the body’s ability to fight disease, according to a new study conducted among young women.
Researchers from Taibah University in Saudi Arabia found that symptoms of anxiety or insomnia were linked to lower levels of natural killer (NK) cells—immune cells responsible for destroying pathogens and infected or abnormal cells. A decline in these cells can compromise immune defence and increase vulnerability to illness.
The study, published in Frontiers in Immunology, involved 60 female university students who completed questionnaires assessing anxiety and sleep disturbances. Blood samples were also analysed to measure the number of circulating natural killer cells.
The findings showed that young women reporting insomnia symptoms had a lower overall number of NK cells. Similarly, participants experiencing anxiety symptoms exhibited reduced levels of circulating NK cells in their bloodstream.
According to the researchers, around 75 per cent of participants reported symptoms of generalised anxiety disorder (GAD-7) at varying severity levels, while more than half experienced insomnia. Students with anxiety symptoms had significantly lower percentages and counts of NK cells compared to those without such symptoms. The decline was more pronounced among participants with moderate to severe anxiety, while those with mild or minimal anxiety showed no significant reduction.
Among students suffering from insomnia, higher anxiety scores were associated with an even greater decrease in total peripheral NK cells.
The researchers noted that a reduced number of natural killer cells could impair immune function and may increase the risk of infections, cancer and certain mental health conditions, including depression.
They added that the findings offer valuable insights into the physiological effects of anxiety and insomnia and could help in developing strategies to prevent immune-related disorders and cancers.
