Anxiety and insomnia weaken the body from within, warns new study

Anxiety and depression: According to the research, students with anxiety showed both lower numbers and lower proportions of circulating NK cells (Image: Pexels)

There was time we thought a cup of tea or coffee could relieve stress. Sleepless nights were a thing to flaunt, and not worry. However, new findings suggest that anxiety and insomnia may be sabotaging the immune system, thinning out some of its most important components.

Natural killer cells, known simply as NK cells, are the immune system’s rapid-response unit. They patrol the bloodstream, hunting down infected, damaged or abnormal cells before trouble spreads. When their numbers fall, the body’s ability to fight infection, inflammation and even cancer may falter.

According to a new study published in Frontiers in Immunology, anxiety and poor sleep appear to be strongly linked to a drop in these crucial cells.

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The research focused on 60 female students aged between 17 and 23 in Saudi Arabia, a group already facing rising levels of anxiety and sleep disturbance. More than half reported symptoms of insomnia, while three quarters described some level of anxiety.

Blood tests revealed a worrying pattern, where, those struggling with anxiety or insomnia had significantly fewer NK cells, particularly the circulating types responsible for destroying harmful cells.

The researchers asked participants to complete questionnaires covering demographics, anxiety levels and sleep quality. Anxiety severity ranged from mild to severe, while insomnia symptoms were self-reported. Blood samples were then analysed to measure different subtypes of NK cells, including those known for their cell-killing ability and those involved in regulating immune responses.

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Dangers of anxiety and insomnia

According to the findings, students with anxiety showed both lower numbers and lower proportions of circulating NK cells.

The more severe the anxiety, the sharper the drop.

Those with moderate to severe anxiety experienced the most pronounced declines, while mild symptoms showed little change.

Among students with insomnia, higher anxiety scores were linked to even fewer peripheral NK cells.

When NK cell levels dip, the immune system loses one of its earliest warning systems. This can increase vulnerability to infections, chronic inflammation, tumours and even mental health conditions such as depression. Researchers believe these immune changes may help explain how long-term psychological stress feeds into physical illness.

Lifestyle, stress and the immune system

The study focused only on young women, meaning the results cannot yet be applied to everyone. Still, the implications are hard to ignore. Previous studies suggest exercise, stress reduction and a balanced dietcan help support NK cell activity. Yet anxiety and insomnia continue to disrupt the body’s natural rhythms. As one researcher shared, these psychological stressors may ultimately compromise both health and quality of life, a sobering thought for a generation already running on empty.