There are many people who associate the arrival of spring with a renewed sense of energy that borders on the frantic. But such spring fever is actually quite the opposite ... at least in the beginning.
Spring fever is a term used to classify a mood change characterized by low energy, fatigue and apathy early in the spring season. Similar to seasonal affective disorder (SAD), spring fever is a mental condition brought on by the change in seasons. It is common in people who also suffer from SAD. Eventually, spring fever may evolve into feelings of restlessness, intense nervous excitement, high-energy spurts and loss of appetite.
The condition is a chemical response in the body to its carcadian rhythm spurred on by sunlight. In the winter, there are fewer hours of sunlight. Sunlight has a direct effect on the production of serotonin and melatonin. Serotonin is the feel-good chemical messenger that affects mood and other bodily functions. In the darker, colder seasons, serotonin can be in short supply, which is why many people feel blue these times of the year. Melatonin is the chemical component that is related to sleep and wakefullness. When there are more hours of darkness, the body produces more melatonin, which in turn makes a person tired.
When the spring season arrives, the body can take a while to readjust to the correct levels. Therefore, a person may initially have residual melatonin and a short supply of serotonin in the early spring, accounting for the tiredness and irritability. As the chemical messengers decrease and increase according to sunlight, the reverse takes effect. Aperson may have extra energy and actually feel little need to sleep.