This may look a little weird or sound a little hyped, but you can really reset yourself in as few as eight breaths, or two minutes.
It's based on the yogic principle of pratyahara: sense withdrawal.
THE SETUP: Sit comfortably, on a chair or on the floor. Place your pinkies together just below your lips. Touch the tip of your ring fingers just above the lips. Gently position your middle fingers against your nostrils, but only press them when you're neither breathing in nor breathing out -- during the pauses. Index fingers press your eyelids shut. (Wait, keep them open so you can keep reading the instructions.) Lastly, the thumbs occlude your ears; i. e., they press the flaps of your ears in to keep out sound. THE PRACTICE: With your eyes and ears shut, take 8 very slow breaths, listening to the sound that they make and pausing briefly at the top of the inhalation (and pressing the nostrils shut with your middle fingers) and at the bottom of the exhalation (again pressing the nostrils). Those extra-slow breaths should go in slowly and deeply and come out unhurriedly; all in all, they should take about two minutes to complete. Just pay attention to the sound of movement of air... or maybe even hear blood pumping in your veins. BENEFITS: You get an immediate boost of alertness that's not unlike having slept a little more. It can really re-center your mind in the midst of a chaotic situation, emotional fluctuations, excessive demands, or multi-tasking distractions. Great to do before meditation. AVOID IF: This position is very gentle, so I can't think of counterindications. If you experience shortness of breath or elevated heartbeat, it's because you're trying to hold the breath instead of letting it flow slowly at its own rhythm. Try to adjust it. Also, if the reason you're doing this is to make up for the fact that you only slept 3 hours last night, it may do the trick... but if you only slept 3 hours because you were out partying and drank too many mixed drinks... the bets are off. :-)