To many people, stress = negative. Does it negatively affect sperm and fertility? The answer may surprise you. It turns out that, months after a stressful incident, sperm motility goes up. It’s what researchers are calling an example of a coping mechanism, in models of both mice and men.

The study published in the journal of Nature Communications showed that exposure to stress altered epithelial cell-secreted extracellular vesicles. An increase in mitochondrial respiration was seen, along with sperm motility, when the vesicles were incubated with mouse sperm. The researchers identified “a time-dependent, translational signaling pathway that communicates stress experience to sperm, ultimately affecting reproductive functions.” Lead author Dr. Tracy Bale* commented, “This timing, where sperm function improves after stress, might be evolutionarily beneficial to increasing birth rates, particularly following challenging times like those experienced during the COVID pandemic.”

The results of the study will help increase knowledge of the impact of stress, leading to a better understanding of the dynamics of fertility. Dr. Bale: “As stress is a common part of daily life, understanding its effects on reproduction and development will be essential for improving fertility and addressing broader ecological impacts on endangered species.” Researchers hope to continue on this path, examining the impact of stress on women’s fertility, as well as brain development in a fetus.

*Anschutz Foundation Endowed Chair in Women’s Integrated Mental and Physical Health Research at the Ludeman Center at CU Anschutz