You can never underestimate the value of fresh air for physical and mental wellbeing. Step outside of your airconditioned house or workplace and breathe it in! Even better if you can be around trees – particularly in forests – because they emit airborne chemicals called ‘phytoncides’ to help protect against insects and rot.
Phytoncides are wood essential oils and are known to be beneficial to humans in lowering blood pressure, elevating mood and inducing a state of relaxation. The Japanese do what they call shinrin-yoku - 'forest bathing' - or taking in the forest through the senses.
If you can’t make it to a forest in your lunch hour, at least put your body in the outdoors for a dose of vitamin D from the sun, some fresh air and a change of atmosphere. Just half an hour can pay dividends for your state of mind and for your sleep that evening.