Breathing through the nose is a natural and healthy way to inhale air into our lungs. In contrast, breathing through the mouth is often a sign of an underlying health issue. Here are some reasons why we should breathe only through the nose and not through the mouth:

Filters and warms up the air
- The nose functions as a natural air filter. It traps dust, dirt, and other harmful particles from the air we breathe in. In addition, the nose warms up the air to match our body temperature before it reaches the lungs. This prevents irritation and inflammation of the airways.

Prevents dry mouth
- Breathing through the mouth can lead to dry mouth, which can cause bad breath, tooth decay, and gum disease. When we breathe through the nose, the saliva in our mouth is constantly circulated, keeping our mouth moist and healthy.

Improves oxygen uptake
- Breathing through the nose allows more oxygen to reach our lungs. The nasal cavity has a high concentration of nitric oxide, which helps to dilate blood vessels and improve oxygen uptake. In contrast, mouth breathing doesn't allow for this important process to occur.

Reduces stress and anxiety
- Breathing through the nose has been shown to reduce stress and anxiety levels. This is because nasal breathing activates the parasympathetic nervous system which helps us to relax and calm down.

Prevents snoring and sleep apnea
- Mouth breathing during sleep can lead to snoring and sleep apnea. This is because mouth breathing causes the airways to narrow and collapse, leading to breathing difficulties. Nasal breathing, on the other hand, keeps the airways open and prevents snoring and sleep apnea.

In conclusion, breathing through the nose is the natural and healthy way to breathe. It filters and warms up the air, prevents dry mouth, improves oxygen uptake, reduces stress and anxiety, and prevents snoring and sleep apnea. Therefore, it is important to practice nasal breathing whenever possible.

We should not breathe through mouth because harmful substances are present air which can go in the body but in the nose fine hair &mucous is present which avoids the germs to go in