Have We Lost Darkness?

Have we lost darkness?

In villages, evening would arrive and the day would naturally end. With fewer lights, the sky was visible. Night meant rest.

Today in cities? At 11 PM, the house is fully lit. Mobile in hand, screen before eyes. We conquered light, but lost darkness.

Why does the body need darkness?

Our body has a biological clock called the circadian rhythm (suprachiasmatic nucleus SCN).

It starts with sunlight and calms down with darkness. When darkness falls, melatonin increases. It's not just for sleep; it's an antioxidant. It helps in immune regulation. It coordinates hormonal rhythm.

What changes does artificial light bring?

1. Melatonin is suppressed Blue light exposure at night can reduce melatonin secretion (controlled lab studies have shown 40–50% suppression). Sleep onset is delayed. Recovery starts later.

2. Sleep quality can decrease Evening screen exposure increases sleep latency and can reduce deep sleep. Deep sleep is the repair window.

3. Impact on next-day sugar handling Short-term sleep restriction studies show that when sleep is reduced, insulin sensitivity decreases. Late-night light + screen exposure can change the metabolic response the next day.

4. BP dipping pattern can be disturbed Naturally, BP decreases by 10–20% at night. Poor sleep and circadian disturbance are linked to a non-dipping BP pattern.

5. Shift work - a major indicator Shift workers have a higher risk of obesity, diabetes, and heart disease.

6. Artificial light + Late night eating = double load Nighttime glucose tolerance is naturally lower. On top of that, late screen exposure and eating can be a dual metabolic stress for the body.

We don't even think about it.

We improve our diet. We walk. We do strength training.

But in the bedroom, standby LED, notification light, mobile screen, always on.

Darkness is not a luxury. It is a biological need.