As a human, you are designed to breathe through your nose. You need to take fewer breaths through your nose than the average mouth-breather takes to deliver the same amount of oxygen to the lungs. As a fighter, breathing efficiently during training will benefit you in many ways; breathing efficiently in competition can give you a huge edge over an opponent.
Because you’ll need fewer breaths through your nose, you’ll actually be able to breathe slower, which in turn will allow you to be more relaxed in the thick of the fight. Plus every breath you save equals precious energy you’ll save as well. You’ll enjoy more stamina and focus, all thanks to your nostrils.
On the other hand, habitual mouth breathing can possibly cause or aggravate a host of medical issues, including asthma and high blood pressure. And due to the inefficiency of mouth breathing, during heavy exertion the individual could resort to gasping for air in order to get the needed oxygen. This means the fighters jaw will open wide to get the air in, putting themselves in danger of losing their mouthpiece and/or making their jaw vulnerable to a punch.
When you’re training try to pay attention to your breathing. Force yourself to breathe through your nose, inhaling AND exhaling. You exhale faster through your nose, which means your lungs are ready to take in the next breath sooner. Try not to mouth breathe at all, even if it means taking the intensity down a notch temporarily. So shut your mouth and get to work. Eventually you’ll breathe effortlessly through your nose and your workout stamina should improve substantially.