The Science of Spring Fever

Why this time of year can trigger feelings of pleasure, pain, or a bit of both

Illustration: Kieran Blakey for Elemental

Spring is a season of rebirth and renewal. Flowers sprout, leaves bud, and the natural world wakes up from its long winter hibernation. Likewise, a lot of people feel rejuvenated as the days grow longer, sunnier, and warmer.

But for some, the transition from winter to spring can be a rocky one. “Some people shift into their springtime mode smoothly, [but] others battle with this transition, suffering the volatility of ‘spring fever’ for a month or more before settling into a calmer summer state,” says Michael Terman, PhD, a professor in the department of psychiatry at Columbia University and president of the nonprofit Center for Environmental Therapeutics.

Terman says that springtime feelings of renewed energy and exuberance are often counterbalanced by periods of despondency or discombobulation. The season can even trigger a kind of temporary manic-depressive disorder. People experience “rapid shifts to high and energetic mood and behavior punctuated by shifts down low, feeling wiped out and despondent,” he says.

Why does any of this happen? The operation of the body’s circadian clocks, which govern everything from mood and appetite to hormone production and immune functioning, can help explain why springtime throws some of us such a curveball.

How springtime can disrupt our rhythms

Every cell and system in the human body contains a clock. These clocks, like the ones on our phones or wrists, keep time and operate on a (roughly) 24-hour cycle. And they’re primarily regulated by daylight. More than any other time of the year, springtime can knock these circadian clocks into disarray.

During the cold, relatively lightless days of winter, Terman says that people tend to sleep longer, eat a bit more, and experience higher levels of daytime fatigue. For most, these “winter lows” are mild or hardly noticeable. But for others, they’re so pronounced that they induce a form of depression known as seasonal affective disorder (SAD). Spring fever, though less studied, may be SAD’s “clinical cousin,” he says. “With the arrival of spring and rapidly increasing daylight availability, spring fever can be viewed as a bumpy emergence out of the consistent winter low.”

Even for people who relish spring, the switch to daylight saving time (DST) can trigger some of the season’s less-pleasant phenomena. For some, that’s an understatement. A 2014 study in the journal Open Heart looked at the effect of spring daylight saving time on heart attacks. On the Monday following DST, the number of heart attacks leaped by 24% compared to the rest of the year, the study found. “Manipulations of the sleep-wake cycle have been linked to imbalance of the autonomic nervous system, rise in proinflammatory cytokines and depression,” the authors of that study wrote in an effort to explain their findings. They said that the heart attacks their study tracked likely would have occurred anyway — albeit spread out over the coming days or weeks. But the “spring forward” and its abrupt disruption of the body’s systems seemed to concentrate many of those attacks on that Monday following the time change.

Spring fever, though less studied, may be SAD’s “clinical cousin.”

Terman likewise highlights DST as a factor that contributes to the unpleasant highs or lows that people may experience this time of year. “The time change presents a second challenge to circadian rhythm stability, just when daylength is rapidly expanding on its trajectory toward summer,” he says. In some, these challenges can trigger a stretch of depression, he says. They can also cause poor concentration and a rise in auto accidents. A 2020 study in Current Biology found that fatal car accidents jump 6% during the week following DST. Some experts have even argued that DST may be “bad for the brain.”

Springtime circadian shifts can also affect the operation of the immune system. A 2016 study from U.K. researchers found that inflammation and other markers of immune activity ebb and flow in response to daily circadian fluctuations. Disruptions to the body’s circadian clocks can in some cases increase inflammation and exacerbate pain or other symptoms. These disruptions can also temporarily increase a person’s risk for infection, that study found.

But while “spring fever” may present challenges for some, the move to longer, light-filled days is generally a happy one. And here again, there’s evidence to suggest that the body’s circadian clocks play a role.

Research in JAMA Psychiatry and elsewhere has found that those brain hormones and neurotransmitters most closely linked to feelings of pleasure and positive affect — namely, serotonin and dopamine — fluctuate in response to sunlight and the circadian shifts it induces. This means we tend to feel better when the weather is sunnier.

Getting sun on our skin may boost some of these pleasant effects, more research suggests. Some experts believe that direct sun exposure not only boosts our vitamin D levels but also sets off a number of other physiological effects that improve our mood, health, and functioning. There’s also a mountain of evidence showing that spending time outdoors and in nature tends to improve people’s mental and cognitive health, perhaps by switching off stress.

How to manage spring fever

While springtime can usher in changes that people may notice — for better or worse — most of these are likely to be short-lived. The human body is adept at regulating itself, and after a period of adjustment, spring fever is likely to pass on its own.

But in some cases, Terman says that the combination of DST and other springtime changes may misalign people’s circadian clocks and daytime schedules in ways that leave them feeling off for weeks or even months.

For these people, getting up and going to bed at the same times each day and also trying to stick with consistent eating and exercise routines may help reset their circadian clocks.

Another option is to take a low-dose of melatonin — just 0.5 mg — roughly four hours before you typically go to bed. “Melatonin helps tell all the parts of the body what time it is,” says Michael Grandner, PhD, director of the Sleep and Health Research Program at the University of Arizona College of Medicine at Tucson.

Grandner explains that the body naturally starts releasing melatonin in the evening, which signals to its cells and systems that the day is nearing its end and sleep is in the cards. But in some cases — like when springtime arrives, and it’s suddenly light out much later in the day — the body’s melatonin release can lag a bit behind. In this situation, taking a little melatonin can help “nudge” the body’s clocks back into a coordinated rhythm.

“Melatonin is very safe when taken at this low dose,” he adds.

I write about health and science. I live in Detroit with my wife and kids. I’m trying to learn German, but my progress so far is nicht gut.

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