Yep, stress is contagious, according to a new University of Calgary study. And worst of all, that stress can impact your brain.
The research – published in the journal Nature Neuroscience – examined sibling pairs of mice, one of which got to chill in its cage while the other was exposed to stress. The stressed out mouse was then reunited with its brother or sister. The researchers found that this resulted in the transmission of a chemical stress signal, or pheromone, from one animal to the other.
A number of prior studies have highlighted the impact chronic stress has on the hippocampus, the part of the brain responsible for learning and memory. Proper memory formation and recall happens when the connections between neurons in the hippocampus are strengthened over time, a process called long-term potentiation (LTP). Prolonged stress weakens these connections, decreasing LTP and diminishing memory.
The University of Calgary study found that not only was the effect of the stress on the hippocampus noticeable in the stressed mouse, it was also seen in the brain of the mouse that had been left alone.
"The neurons that control the brain's response to stress showed changes in unstressed partners that were identical to those we measured in the stressed mice," first study author Toni-Lee Sterley told Medical News Today.
But there’s one upside, for women at least.
The study showed that female mice who were stressed by contagion were able to reverse the effect on their brains by hanging out with other, unstressed mice. This finding was not found in males.