When I'm busy I sometimes need an energiser booster. I use a short Tai Chi energiser for 5-30 seconds, and I have several techniques that I adapt so I can use them in private and/or public areas.
Abdominal breathing is one I use anywhere and any time. It not only energises me but also calms my mind. I teach this technique in all the workshops I run for aged care residents and sports coaches and players.
The basics of abdominal breathing are to breath in through the nose and expand your stomach then breathe out of your nose and relax your stomach. Repeat this process several times.
There is much more to abdominal breathing in Tai Chi, but what I have described makes for a good start.
Image courtesy of Jonathon Sebastaio via Unsplash