Stress Paralyzes Immune Cells
A research team in Australia led by immunologist Scott Mueller injected a stress hormone, norepinephrine, into the bloodstreams of mice. The purpose was to see how immune cells responded to stress hormones. Within just a few minutes, T-cells stopped moving. To make sure it was the stress hormone and the injection itself, the researchers performed the same experiment using dopamine, which had no effect on immune function.
To further research the issue, researchers infected the mice with herpes simplex virus (HSV). After two days the mice were treated with a molecule called Iso that mimics the action of adrenaline, a stress hormone. This also stopped the action of T-cells and dendritic cells for over two hours. When another substance called salmeterol, which acts on the same receptors, was injected two times per day for three days, there were fewer virus-specific T-cells at the sites of infection. Additional experiments with mice injected with melanoma cells or malaria parasites showed the same result – stress hormones and substances that mimic them suppress immune function.
There are other mechanisms at work too:
- In response to intense fear or stress, messages from the brain are sent to the endocrine system
- The adrenal glands release adrenaline and noradrenaline
- The body gets ready for fight or flight
- The heart beats faster, and blood pressure rises to send more blood to the arms and legs
- Extra glucose and fat are released for energy
This cascade of events works well for short-term situations in which people must act quickly to survive but does not work well when lower-level stress and anxiety becomes a chronic condition.
Stress also activates responses like inflammation, which helps to repair damaged or infected tissues. Inflammation causes white blood cells to flood an area where an injury has occurred, and release cytokines and recruit macrophages to clean out debris and dead cells. Inflammation is helpful for healing injury; not so much when stuck in the “on” position due to being in a continuous state of fight or flight.
Remaining constantly stressed about viruses makes you more likely to get sick from viruses. Here are some recommendations to reduce your stress:
- choose sources of information that do not result in increased stress
- carefully choose the people you hang around with – some have become toxic sources of stress and panic
- focus on strategies like eating well, exercising, getting out in the sunlight, drinking water – you will feel less stressed about health if you are healthy
- practice gratitude – thinking about what is good in life shifts the focus from the things that are not as good.
Devi S, Alexandre YO, Loi JK et al. “Adrenergic regulation of the vasculature impairs leukocyte interstitial migration and suppresses immune responses.” Immunity 2021 Jun;54(6):1219-1250
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