If you thought spring fever was a myth concocted by uninhibited spring breakers in Cancun, think again. Those feelings of restlessness and excitement that crop up each spring may not all be in your head.Although the jury is still out on whether people really are affected by the change in daylight which happens at spring’s arrival, several studies have shown a link between seasonal variations in day length and changes in melatonin (the hormone that plays a role in regulating the sleep-wake cycle) and serotonin (that “feel-good” hormone linked to mood, appetite, energy balance and sleep).COLUMN: Dr. Oz & Dr. Roizen Explain How Melatonin WorksNotice how you’re no longer heading home after work in the dark? Now that we’ve passed spring equinox—a point at which day length and night length were equal—the sunny days are only getting longer. That significant increase in hours filled with daylight appears to have a direct effect on life processes such as eating, sleeping, mating and mood.”The longer days engage brain systems associated with psychological arousal,” explains YouBeauty Psychology Advisor, Art Markman, Ph.D., “That arousal increases the power of your emotions. It gives you a lot of energy to move around, which can make it hard to sit indoors all day.”So you’re not imaging things if you feel more restless and are itching to be out and about come springtime. You can also blame it on the warmer weather, according to Markman.MORE: Daylight Savings: Beauty Bust or Boost?“The warmer weather encourages us to shed all of the layers of clothes we have been wearing,” he says. “That makes us more attuned to our senses. As a result, we are less interested in being cooped up indoors and that can make it harder to complete tasks in school and at work.  It also increases sexual arousal, because we’re around a lot more skin than we were before. That can also be distracting.”What can you do if you’re feeling restless this spring? Try eating certain calming, feel-good foods—ones that boost melatonin and serotonin. “There’s a lot of serotonin located in the gut,” explains Nicolette M. Pace, R.D., founder of Nutrisource, which offers nutrition counseling services. “There is some evidence gaining increased attention that friendly gut-bacteria help promote this gut-brain connection, so it would follow that promoting a healthy gut with probiotics is a good step.”Pace recommends eating foods rich in the amino acid tryptophan, which is dietary precursor to serotonin and melatonin. Soy, lean meats and fish are good sources, as well as dairy products and whole grains. Another yummy source: chocolate, which raises levels of serotonin in the brain (there’s a reason you crave chocolate after a crummy day).MORE: Eat Chocolate, Slim DownAs far as melatonin, there are natural food choices for that, too. “More people are taking melatonin supplements nowadays, but it does occur naturally in mostly seeds and herbs,” explains Pace. “Things like flax seeds and anything in the celery and fennel family are very useful.”Adds Pace: “It really all comes down to those seasonal, natural, whole foods that will pretty much cure your spring fever and will help you make the most of this enlightening time of year.”