Although chronic stress is known to be bad for you, a new study of rats reveals that short-term stress can actually help boost your immune system.

The study, published online in the Journal of Psychoneuroendocrinology and conducted by researchers from the Stanford University School of Medicine and two other universities, adds weight to evidence that immune responsiveness is heightened by the so-called “fight or flight” response.

According to the researchers, their findings offer the prospect of, someday, being able to manipulate stress-hormone levels to improve patients’ responses to vaccines or recovery from surgery or wounds.

Chronic stress has detrimental effects including suppression of the immune response. However, lead author of the study Firdaus Dhabhar, Ph.D., an associate professor of psychiatry and behavioral sciences and member of the Stanford Institute for Immunity, Transplantation, and Infection, explained that short-term stress stimulates immune activity.

The immune system plays a vital role in protecting our bodies against diseases, fighting infection and in healing wounds.

Dhabhar explained: “Mother Nature gave us the fight-or-flight stress response to help us, not to kill us.”

According to the researchers, the findings describe the body’s finely coordinated system to detect danger and prepare to protect itself. Dhabhar said:

“You don’t want to keep your immune system on high alert at all times. So nature uses the brain, the organ most capable of detecting an approaching challenge, to signal that detection to the rest of the body by directing the release of stress hormones. Without them, a lion couldn’t kill, and an impala couldn’t escape.”

In the study, the researchers subjected rats to mild stress by confining them (gently, and with full ventilation) in transparent Plexiglas enclosures. The team drew blood several times over a two-hour period and discovered that the stress caused a massive mobilization of several key types of immune cells into the bloodstream and other parts of the body.