Stress is the response of the human body to demands, challenges, or threats — often serving the purpose of avoiding or fighting off danger or, in our everyday lives, meeting deadlines by working harder or staying awake longer. While stress is considered essential for survival, exposure to chronic stress or experiencing overwhelming stress at once can undermine one’s physical and mental health — commonly, in the form of increased heart rate and blood pressure, nausea, dizziness, and headaches. And less commonly, in the form of psychogenic fever — that is fever with a psychological origin, rather than a physical one.

“[Psychogenic fever is] a phenomenon… where stress seems to raise core body temperature in the absence of other inflammatory processes such as infection or injury,” Dr. Katrina Miller Parrish from Los Angeles in the U.S., told Stress. While anyone undergoing stress may experience psychogenic fever, it is most commonly observed in the younger female population.

According to the U.S. National Library of Medicine, an individual’s “normal” body temperature lies between from 97°F to 99°F. “An adult probably has a fever when the temperature is above 99°F to 99.5°F, depending on the time of day,” the organization states on its website. Psychogenic fever, generally, manifests in two forms — either in the form of persistent low-grade fever, between 99°F to 100.4°F, or through a sudden a spike in body temperature that can reach as high as 104°F. While the former is often a result of chronic stress, the latter may result from an “acute incidence of severe stress, due to trauma or an emotional upheaval.”

“Some patients develop a high fever when they are exposed to emotional events, whereas others show a persistent low-grade fever lasting months and even years, either during or after situations of chronic stress,” Dr. Takakazu Oka from the Kyushu University Graduate School of Medical Sciences in Japan, who extensively studies the subject, told Health.

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The symptoms of psychogenic fever can be similar to “regular” fever and may cause individuals dealing with it to experience chills, headaches, and nausea, besides feeling hot, flushed, or fatigued.

However, research on the subject is still sparse; so much so that a 2015 study noted how “there are still physicians who do not recognize the fact that psychological stress can cause ‘high’ body temperature.”

Due to a lack of research on the subject, experts are still unsure exactly how stress induces fever. But a study published last year found that in rats, stress affects the hypothalamus, an area of the brain that controls body temperature. Scientists are yet to determine whether the same mechanism applies to humans.

Research suggests that common anti-inflammatory medications used to treat “regular” fever, aren’t particularly effective against psychogenic fever — for the simple reason that “if a fever is due to stress, it is essential to decrease the stress,” according to Dr. Miller Parrish.

“Depending on the cause, the antidote could be cognitive-behavioral or other psychological therapy, meditation, yoga, and practices that focus on decreasing a stressful state, or perhaps even medication to treat the issue,” she added.