CO2 output is based on respiration. I have never heard anyone on any exercise oriented website advocate a high fat diet. There is so little nutrients in fat as to be pointless to add them. Athletes might not avoid them, but they certainly don't go trying to SPECIFICALLY add fat to the diet unless they can not maintain or gain weight. Few athletes fall in those categories.
My new son-in-law plays basketball, and used to have burgers nearly every meal. My daughter and I convinced him to give them up. He said he feels better, sleeps better, feels stronger, gets less tired, and rarely ever gets headaches anymore. With less fat in his diet.
Higher fat diets, and higher body fat, interfere with the bodies inflammation fighting ability.
I am not into "athletic medicine", whatever that is. Other technical gobbledygook posted sounds bogus and is not clear as stated. Maybe to a doctor or exercise physiologist.
In fact, I am amazed that I am maintaining a higher weight on less calories eating a low fat diet. I used to have 800-1,000 calories nightly trying to keep my weight up to 158 or so, where it now seems stable. I exercise less than before, but the main difference is taking out 108 flight of stairs, up and down, 5 days a week, and three 90 minute weight workouts a week. My lunch was a large bowl of stir fry using olive and canola oil. I had a couple burgers on the weekend, and pizza occasionally.
Based on my experience, people's health will improve in proportion to the amount of fat they stop eating, and the addition of exercise, about an hour a day, or 2,200 calories a week.
We are muscular creatures meant to move. We can run, swim, climb, and engage in myriad other activities. I never bother to test my breath holding ability. Voluntarily raise the level of CO2 in the blood ? WHY ? Sneak in a little extra oxidized LDL ? No, thank you.
How about playing basketball or rowing for an hour without breathing changes, even though one is working very hard and the heart rate hits 100% of 220 - age ?-
Endurance increases as circulation and strength improve in the muscles used, especially the heart.
Heretic: Please let us know when you are at 7% or 20% of cardiac blood flow, and what kind of athletic endeavors you are doing at that time. 7% was where I was prior to bypass surgery. 20% is where I am with the dozen inoperable blockages I had and still have. Without an angiogram in 3 1/2 years, I don't know if the blockages have improved. They probably have, based on my current level of athleticism and healthy LOW FAT diet.
Sharks feed primarily on fatty sea mammals. Of course they also swim nearly 24 hours a day mainly in cool water.
Great apes are primarily vegetarian, and are incredibly strong.
More than minimal fats and oils make me gag, and always have. My roommate in college was lot bigger than me but a worse athlete. He switched to my diet at that time, and improved so much in 3 years he won a National Championship in pairs rowing. He mainly cut fatty foods, and added fruits and veggies.