Feeling sluggish, heavy, or having "leaden" energy levels.
Individuals with winter SAD often experience "atypical" depressive symptoms: seasonal affective disorder
But for a significant portion of the population, the changing season triggers a profound biological mutiny. It is more than just the "winter blues." It is a distinct, clinical reality known as Seasonal Affective Disorder (SAD), a condition that turns the colder months into a marathon of endurance. Feeling sluggish, heavy, or having "leaden" energy levels
Less frequently, SAD can occur in the spring and summer. Symptoms for this pattern differ notably: Seasonal affective disorder (SAD) - Symptoms & causes Less frequently, SAD can occur in the spring and summer
The prevailing theory centers on the disruption of our circadian rhythm—the body’s internal master clock. As daylight hours shrink, the brain’s regulation of key neurotransmitters goes awry. Reduced sunlight triggers an overproduction of melatonin, the sleep hormone, leading to lethargy and grogginess. Simultaneously, serotonin levels—a key player in mood regulation—tend to drop.
Seasonal affective disorder (SAD) - Symptoms & causes - Mayo Clinic