Health. Why does stress weaken the immune system?

Have you ever noticed that during periods of more or less intense psychological stress, you have the annoying habit of catching a cold? Or catching every virus that's going around? This famous stress is not innocent! And for good reason: it tends to weaken our immune defenses, the true bulwarks against viruses and other bacteria.

Acute stress actually causes the release of adrenaline and noradrenaline, two neurotransmitters that in turn alter the functioning of NK lymphocytes (Natural Killer) or natural killer cells. Of viruses and bacteria, in this case!

Targeted receptors

The scientific explanation came in 2020, thanks to the work of a French team from Inserm and the CNRS, led by Sophie Ugolini (Inserm – Marseille-Luminy Immunology Center). The researchers observed stimulation of β2-adrenergic receptors by stress hormones in mice.

And it is these receptors that are thought to be responsible for weakening the immune system. Indeed, these receptors inhibit the response of certain cells, the NK cells. The result: the more β2 receptors there are, the less effective the NK cells are. They are prevented "from producing a particular type of cytokine required to enable the elimination of viruses," the scientist added.

A treatment?

This discovery outlines potential therapeutic avenues: "By targeting the β2-adrenergic receptor, it would indeed be possible, in certain pathological contexts, to lift the immune brakes caused by a state of stress," concluded Sophie Ugolini. In the meantime, the challenge remains above all to work on the levers at your disposal to reduce this stress: breathing, meditation, good sleep hygiene and even physical activity.