Sunlight helps reduce melatonin, the hormone responsible for sleep
In today’s screen-driven world, millions spend most of their days indoors — working, relaxing and socialising within four walls.
While this lifestyle feels convenient, growing research shows it may come at a serious cost to the body and mind.
Spending less time outdoors often means reduced exposure to sunlight, which directly affects serotonin — a neurotransmitter linked to mood regulation. Often called the “happiness chemical,” serotonin helps maintain emotional balance.
A study by the University of Cambridge found that staying indoors for long periods leads to lower serotonin production, which may also increase aggressive behaviour.
Natural morning light plays a key role in regulating the circadian rhythm, the body’s internal sleep-wake cycle. Without regular exposure to daylight, this system can become disrupted.
Sunlight helps reduce melatonin, the hormone responsible for sleep. When people remain indoors — especially while exposed to blue light from screens — melatonin levels stay high, making mornings feel exhausting. Sleep expert Professor Kenneth Wright notes that the brain may continue signalling the body to stay asleep even after waking.
Increased body aches
Not going outside reduces sun exposure, increasing the risk of vitamin D deficiency. Vitamin D is produced naturally when skin is exposed to sunlight and is essential for bone and muscle health.
A 2003 study revealed that 93 percent of people suffering from chronic pain had extremely low vitamin D levels, linking indoor lifestyles to persistent physical discomfort.
Digestive system can be affected
Healthy vitamin D levels are also crucial for gut health. A deficiency may not only cause general discomfort but also disrupt digestive function.
This connection highlights how limited sun exposure can affect more than just bones and muscles.
Cabin fever can set in
Prolonged time in enclosed spaces can trigger what is commonly known as cabin fever. Symptoms vary but often include fatigue, irritability and a general feeling of unease.
One study identified these emotional and physical symptoms as common responses to extended indoor confinement.
May increase allergies
Allergies, including seasonal ones, have become more common over time. Scientists believe reduced outdoor exposure may be a contributing factor.
Vitamin D is thought to activate immune cells that help limit severe allergic reactions. Ironically, spending more time outside may actually help regulate allergy responses.
You may feel more stressed
Many people retreat indoors when feeling overwhelmed or exhausted, seeking comfort at home. However, mental health experts suggest this can have the opposite effect.
Psychotherapist Owen Okin explains that natural sounds, light and scents send calming signals to the brain. Time outdoors increases serotonin and dopamine levels, helping the mind slow down and feel more at ease.
Increased Risk Of Cancer
While excessive sun exposure raises the risk of skin cancer, too little sunlight has been linked to other cancers.
Researchers at the Commonwealth Medical College found that nearly three-quarters of cancer patients studied had low vitamin D levels, highlighting a potential long-term risk of avoiding sunlight altogether.
Cognitive abilities, including memory, naturally decline with age. However, exposure to natural environments may help slow this process.
A 2008 University of Michigan study found that participants who took walks in nature experienced a 20 percent improvement in short-term memory.
You may be depressed
Clinical psychologist Stephanie J. Wong warns that prolonged indoor isolation can worsen symptoms of depression. While resting indoors may feel comforting at first, it often reduces motivation and engagement in daily activities over time.
This cycle can deepen emotional withdrawal and impact overall mental wellbeing.
Constant fatigue is another consequence of limited outdoor activity. Vitamin D deficiency can cause both mental and physical exhaustion.
Additionally, indoor lifestyles often involve less physical movement. Research shows that natural environments boost energy levels, making people feel more alert and active.
