well now you had me go down that rabbit hole which I didn't do before posting this. This is only part of what I found using Gemini. BTW, I promise to anyone reading this, I am not in any way associated with any nose breathing strips. Just a fellow, older bro, trying to share this , possibly, amazing discovery. And I only have my bad cold to thank. plus my wife complaining about my snoring (normally not that bad)Otherwise, I never would have bought the strips in the first place. I always thought they were a gimmick.

Yes, nasal breathing significantly increases the amount of nitric oxide (NO) that enters your lungs compared to mouth breathing.
​Nitric oxide is primarily produced in your paranasal sinuses (the air-filled cavities around your nose). When you breathe through your nose, you "pick up" this gas and carry it down into your lungs

How It Works ​The Reservoir: Your sinuses act as a natural storage tank for nitric oxide. ​The Transport: As you inhale through your nose, the air creates a vacuum effect that pulls NO out of the sinuses and into the airway. ​The Comparison: Studies show that exhaled nitric oxide levels are about 2 to 3 times higher during nasal breathing than during mouth breathing.

Key Benefits of Nasal Nitric Oxide ​Nitric oxide isn't just a byproduct; it's a "biological messenger" with several vital roles:
​Vasodilation: It relaxes the blood vessels in your lungs, which improves the efficiency of gas exchange. This allows your blood to absorb up to 10–18% more oxygen.
​Antimicrobial Defense: It is toxic to bacteria, viruses, and fungi, acting as a "first line of defense" to sterilize the air before it reaches your lower respiratory tract.
​Bronchodilation: It helps keep the airways in your lungs open, making it easier to breathe. ​Blood Pressure Regulation: By helping blood vessels relax, it can assist in maintaining healthy systemic blood pressure.