Is It Self-Suggestion or a Biological Need?
When the sky is overcast, sometimes a cup of coffee isn’t enough. Thoughts keep circling around the pillow, and focusing on a business meeting becomes an enormous challenge.
There are several reasons for this. The first is a lack of oxygen in the blood. When atmospheric pressure drops, our body lowers blood pressure and reduces heart rate. The oxygen concentration in the blood decreases, affecting the activity of nervous tissue in the brain—it also slows down. As a result, drowsiness sets in.
The second reason is related to melatonin levels, the “night hormone.” Sunlight blocks its production in the body, while cloudy skies disrupt the biological clock—the body simply doesn’t understand why it’s being forced to stay awake when it’s dark outside.
Rain itself has a soothing effect. The falling droplets create a steady, uniform sound—often referred to as white noise. Other examples include rustling leaves, wind, waterfall sounds, and other monotonous noises. These help relax the mind and promote faster sleep.
Post-rain drowsiness occurs due to increased ozone formation in the air. Additionally, the earthy scent plays a role. All grasses, plants, and trees contain volatile aromatic compounds. Rain washes them out, mixing them with geosmin—an organic substance produced by bacteria responsible for the earthy smell. This creates a distinct, relaxing aroma.
However, some plant scents have the opposite effect, boosting alertness. These include lemon, rosemary, lavender, jasmine, and pine. Try placing essential oil from one of these plants in your room—sleepiness will vanish instantly!
