Spending just 20 minutes a day in a park or other natural environment can significantly reduce stress and improve mood without any exercise. 1. Physiologically: The natural environment lowers cortisol (a stress hormone) and increases dopamine/serotonin. 2. Psychologically: Gentle stimuli such as greenery and birdsong allow the prefrontal cortex to rest, restoring focus and relieving mental fatigue. The key is "spontaneity": no special planning required. Take a stroll in a nearby park during your lunch break or after work, put down your phone, and feel the wind, sunshine, and plants – a low-cost form of healing.