henry copeland:

The Yogi masters were right -- meditation and breathing exercises can sharpen your mind: New research explains link between breath-focused meditation and attention and brain health -- ScienceDaily

Michael Melnychuk, PhD candidate at the Trinity College Institute of Neuroscience, Trinity, and lead author of the study, explained: "Practitioners of yoga have claimed for some 2,500 years, that respiration influences the mind. In our study we looked for a neurophysiological link that could help explain these claims by measuring breathing, reaction time, and brain activity in a small area in the brainstem called the locus coeruleus, where noradrenaline is made. Noradrenaline is an all-purpose action system in the brain. When we are stressed we produce too much noradrenaline and we can't focus. When we feel sluggish, we produce too little and again, we can't focus. There is a sweet spot of noradrenaline in which our emotions, thinking and memory are much clearer." "This study has shown that as you breathe in locus coeruleus activity is increasing slightly, and as you breathe out it decreases. Put simply this means that our attention is influenced by our breath and that it rises and falls with the cycle of respiration. It is possible that by focusing on and regulating your breathing you can optimise your attention level and likewise, by focusing on your attention level, your breathing becomes more synchronised."
- www.sciencedaily.com