This is a very simple relaxation technique I'll teach you that will help you to consciously relax at any point during your day and restore your mind to a state of calm. It's the quickest, most effective way to Reduce Stress in any situation, so I'll teach you how to incorporate it into your day in a series of 'Breath Breaks'.
If you're a competitive sportsman or woman, practising this technique regularly and in the build-up to your event will help you to Relax and not burn up too much mental and emotional energy before your match or race so you come into your race or match mentally relaxed, calm and clear, but with the optimal amount of cortisol and adrenalin (stress hormones) in your system to perform at your peak in the 90-minute period of the game.
If you go onto the field in a state where you are either over-aroused, i.e. have too much cortisol and adrenaline in your system, or under-stimulated, i.e. you're too relaxed and lackadaisical, you cannot perform at your peak and will tire more quickly if you are over-stressed or be 'flat' and unfocussed if you are too relaxed.
The technique works because deep nasal breathing activates the parasympathetic nervous system rather than the sympathetic one and also creates alpha-range brainwave patterns, which means that doing it naturally relaxes both the mind and body, countering the tendency to go into the 'fight-or-flight' state that is triggered by anxiety and excessive thinking about the outcome of a game and a player's own performance.
If you're a player or the coach of a team, doing these relaxation sessions together as a team rather than individually will also help to unify the team and create a Team Spirit that will translate into better performance on the pitch.