Springtime lethargy refers to a state of fatigue, lowered energy, or depression, associated with the onset of spring. Such a state may be caused by a normal reaction to warmer temperatures, or it may have a medical basis, such as allergies or "reverse" seasonal affective disorder. In many regions, there is a springtime peak in suicide rates.
Psychological and socio-cultural factors also play a role. The opening lines of Eliot's classic poem express some of the complex emotional associations that may be familiar to those who experience dark moods in the spring:
April is the cruellest month, breeding
Lilacs out of the dead land, mixing
Memory and desire, stirring
Dull roots with spring rain.
Occasionally, such lethargy or depression may be described as "spring fever", though this term usually relates to an increase in energy and restlessness, or to romantic and sexual feelings, in the spring.
The German term Frühjahrsmüdigkeit (lit. "Spring fatigue") is the name for a temporary mood or physical condition, typically characterized by a state of low energy and weariness, experienced by many people in springtime. It is not in the category of a diagnosed illness, but rather a phenomenon thought to be initiated by a change in the season. Reportedly an estimated 50–75% of people in Germany have experienced its effect.
In the northern hemisphere the symptoms usually arise from mid-March to mid-April, and depending on the person may be more or less pronounced. Weariness (despite an adequate amount of sleep), sensitivity to changes in the weather, dizziness, irritability, headaches, and sometimes aching joints and a lack of drive are the most common.
Although the causes of this springtime lethargy have not yet been fully resolved, hormone balance may play a role. According to this hypothesis the body's reserves of the "happiness hormone" serotonin, whose production depends on daylight, become exhausted over the winter, making it especially easy for the "sleep hormone" melatonin to have its effect. When the days become longer in springtime, the body readjusts its hormone levels, and more endorphin, testosterone and estrogen are released. This changeover puts a heavy strain on the body, which responds with a feeling of tiredness.
In addition, temperatures usually fluctuate greatly in springtime. When temperatures rise, a person's blood pressure drops, since the blood vessels expand. The expansion of blood vessels is called vasodilation. Food also plays a role. In winter one tends to consume more calories, fat and carbohydrates than in summer. But during the hormone adjustment period the body requires more vitamins and proteins instead.
- Wasmer Andrews, Linda (Mar 28, 2012). "When Spring Brings You Down". Psychology Today. Retrieved November 25, 2016.
- Hegarty, Stephanie (May 29, 2011). "Reverse Sad: Why springtime can be bad for depression sufferers". BBC World Service. Retrieved November 25, 2016.
- Borchard, Therese (April 16, 2014). "April Is the Cruelest Month: Why People Get Depressed and Anxious in the Spring". Everyday Health. Retrieved November 25, 2016.
- Wagner, Beate (2007). "Der verkappte Winterschlaf" [The Undiagnosed Winter Sleep] (in German). Zeit Online. Retrieved November 25, 2016.