Whistle breath for troubled times- soothe your mind and soul by playing with the breath

Whistling is a time- honoured tool to play with the breath and hence the nervous system. It forces your breathing to elongate and triggers all the good things that long deep breathing does for you. Men in wartime marched to the whistled song. By elongating the breath, you change the chemical composition of your blood and hence your bodily functions and soothing and leveling the mind and hence mood.
This is just one of many tools in the kundalini yoga tradition to manage your energy and your aura.