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By Vivian Manning-Schaffel

Now that spring has truly (and finally) sprung, a feeling of restlessness permeates the air, as if we’ve all been set loose from our cages. Clichés might dictate we clean out our closets, which is a useful way to pass the time during a chilly May shower, but if the sun’s out and it starts heating up, mundane tasks are the last thing any of us want to do. Instead, we’d much rather head outside, taking in some sun, blowing off work, even cruising potential mates to play with. Could the root cause of all this friskiness be “spring fever”? And is spring fever even a real thing?

Though it’s far from a medically diagnosable condition, there may be something to this spring fever business, or so say these experts.

Dr. Normal Rosenthal, Clinical Professor of Psychiatry at Georgetown University School of Medicine, author and renowned seasonal affective disorder expert, sees symptoms of spring fever in some of his patients and friends. “It manifests in different ways,” he says. “Sometimes it’s a sheer exuberance. People are smiling, laughing and celebrating the return of longer days and warmer weather. It’s a fever in the best sense of the word. We feel amorous. As the poet Tennyson said, ‘In spring, a young man’s fancy likely turns to thoughts of love.’”

Your brain and body on spring

So what brings “spring fever” on? For one, an increase of daylight can help right whacked-out circadian rhythms, or the biological clock ticking away in your brain, helping you to sleep better at night and be more alert during the day. Kathryn A. Roecklein, Ph.D., associate professor, Department of Psychology at the University of Pittsburgh and seasonal mood expert, explains: “There are numerous anecdotal pieces of evidence that some people feel energized, higher spirits and sleep better in spring. Light has two types of effects. First it tells the circadian clock when dawn occurs, keeping our bodies synchronized to earth. Second, light has acute alerting effects that can make people feel less depressed, more alert, cognitively better able to process tasks, and more energetic within just a few minutes.”

People are smiling, laughing and celebrating the return of longer days and warmer weather. It’s a fever in the best sense of the word.

More daylight can also release signals in your brain that boost your mood, says Rosenthal. “Although there are probably many biochemical and physical changes occurring when the days are expanding most rapidly, the best information we have relates to brain serotonin concentrations that have been found to be increasing in relevant parts of the brain this time of year,” Rosenthal explains. “The receptive neurons, starved of serotonin through the winter months, are now flooded with this neurotransmitter, which is known to be important for mood regulation. The result of this flood impacting extra sensitive receptors may be spring fever.”

Serotonin seems to be a key player in the spring fever phenomenon. One study, published by Innovations in Neuroscience, explores the possibility that sun stimulates serotonin production through your skin, which explains the urge to be outside as much as possible when it’s nice out, and why sunbathing appeals to so many.

Also interesting: Roecklien says changes in the size of the hippocampus — the part of your brain that controls mood and memory — can also occur in spring. She points to a 2015 study that examined how the size of the human hippocampus related to shorter or longer days, or what the scientists referred to as “photoperiod conditions.” Though the scientists recommended additional studies to examine this phenomenon further, a correlation was established between hippocampus volume and seasonal variations in mood — the shorter the day, the smaller the hippocampus — theoretically supporting using bright light therapies to help with mood and eating disorders.

As far as the friskiness of spring fever goes, Rosenthal suspects the sudden urge to cruise for potential mates may stem from a hormonal rush. “In men, increased levels of circulating testosterone have been documented in summertime, a rise that may begin in spring. This hormone is well known to increase amorous feelings in both men and women,” he says. Indeed, one European study tested the testosterone levels of 80 men in both winter and summer, and found, though within normal limits, their levels to be more elevated in summer.

Though everything is in bloom, spring can also usher in some less-than-rosy health situations

Seasonal allergy sufferers might argue spring fever is a special kind of hell. The crazy pollen counts of flowering trees can make them miserable and spring thunderstorms can cause asthma epidemics because the pollen is easier to breathe in. Also, sudden drops in barometric pressure and temperature can bring misery to migraine sufferers, and cause arthritis flare-ups.

The bright side? At least the serotonin boost from the sunshine might help soften the blow.

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