In my times of professional fighting, I liked arriving at the venue three hours before putting on the robe and jumping into the ring.
I'd go with my team to the locker room and, to the surprise of those who did not know me, I'd go to a comfy corner and take a nap. I'd usually sleep for one hour thirty, one hour forty minutes.
My recipe for sleeping soon before a decisive match came down to the lungs. I would breathe in, breathe out, relax my body and especially my head, and sleep deeply, like an infant.
I'd wake up when there were sixty minutes to go, and start a warmup that lasted forty-five minutes. In this stage, my heartbeats would reach 160, 140, and the sweat would start running down. My body was already prepared for the crunch.
And then I would sit for five minutes. It was enough to use my lungs to breathe in and out, and drastically lower my heart rate. Meanwhile, my opponent on the other side would jump, run, make faces, his heart rate way up.
When the fight started, I was always at an advantage in relation to the heart rate and breathing. That's what would lead my opponents, sooner than me, to get their heads confused, make tactical errors, see their arms get too heavy.
Breathing, therefore, was always my best friend as a fighter. And better still: it's the best weapon also for people who will never need to put on fighting gloves or a gi.
After all, as I learned across so many years of locker rooms and training sessions, the lungs play quite a role in our body: they are the true caretakers of our brain and our heart.
Try this as soon as possible: fill your lungs to the brim and exhale slowly and gradually. Repeat the process for three minutes. You will comprehend that it will be impossible to think about problems and errands; after all, your brain starts focusing on the commands of the respiratory movement, deterring any stressful thoughts. As a bonus, you slow down your heart.
Then, you will feel, like I felt on those days of war, a peace that is hard to describe.
Breathe, and be happy.