Health professionals in Portugal have warned that extended periods without sunlight may influence emotional wellbeing, sleep cycles and daily energy levels. According to experts cited by the healthcare organisation Bupa, natural light plays a crucial role in regulating biological processes that support mental and physical health.
Scientific evidence indicates that exposure to daylight contributes to the regulation of Serotonin, a neurotransmitter strongly linked to mood stability and emotional balance. Sunlight also helps synchronise the body’s circadian rhythm — the internal biological clock responsible for controlling cycles of sleep and wakefulness.
Seasonal changes and emotional responses
Research referenced by the Ordem dos Psicólogos Portugueses suggests that lower levels of daylight, typically experienced during autumn and winter, are associated with noticeable changes in mood and daily functioning in Portugal. Individuals may experience alterations in sleep quality, energy levels and emotional regulation as the circadian rhythm adjusts to reduced environmental light.
For most people, these changes tend to be temporary and relatively mild. Commonly reported symptoms include increased fatigue, lower motivation and subtle shifts in mood. However, specialists note that in some individuals these effects may become more pronounced and potentially affect overall wellbeing.
Biological mechanisms behind mood fluctuations
Medical experts explain that diminished exposure to natural light can influence several biological pathways. Lower sunlight levels may reduce the production of serotonin while simultaneously altering the release of Melatonin, a hormone that regulates sleep patterns. These changes can lead to feelings of tiredness and decreased daytime alertness.
In addition, sunlight plays a significant role in the body’s synthesis of Vitamin D. Reduced exposure may contribute to lower vitamin D levels, which some scientific studies have associated with a higher prevalence of depressive symptoms.
In countries such as Portugal, where outdoor activities and social interactions often take place in sunny environments, the contrast created by consecutive cloudy days may be particularly noticeable. Experts note that the body may require a short period of adaptation as many physiological processes are closely linked to the natural light–dark cycle.
Strategies to support emotional wellbeing
Healthcare specialists recommend several practical measures to help maintain emotional balance during periods of reduced sunlight. Spending time outdoors during daylight hours can help stimulate biological rhythms, even when the sky is overcast. Outdoor light remains significantly stronger than typical indoor lighting and may support the body’s natural regulatory systems.
Maintaining consistent sleep schedules is also considered important. Regular bedtimes and waking times help stabilise the circadian rhythm and may improve sleep quality while reducing daytime fatigue.
Physical activity can further support mental wellbeing. Exercise promotes the release of neurotransmitters associated with positive mood and improved sleep. Even moderate activities such as brisk walking or home-based exercises can contribute to maintaining stable energy levels.
Nutrition may also play a supporting role. Health professionals advise including foods naturally rich in vitamin D, such as oily fish, eggs and fortified dairy products, to help maintain adequate nutrient levels during periods of lower sun exposure.
When to seek professional support
Psychologists emphasise that environmental factors can influence how people interpret their own physical and emotional sensations. Feelings of fatigue or low motivation during darker periods may sometimes be perceived as more serious problems than they actually are.
However, if symptoms such as persistent low mood, sleep disruption or loss of energy continue for more than two weeks and begin to interfere with daily life, relationships or work, specialists recommend seeking professional guidance. Access to mental health support — either in person or through telehealth services — may help individuals manage these symptoms more effectively.
As research continues to explore the relationship between environmental factors and mental health, experts underline the importance of recognising how natural light exposure contributes to overall wellbeing, particularly in countries such as Portugal where seasonal variations in daylight can influence daily routines and emotional health.