A guide for Avians

Hemoglobin - How We Will be Able to Breathe at High Altitudes

Hello everyone! It's been a while since Ive updated this, but recently, i went mountain biking (and proceeded to almost pass out) and my mom was talking about how since we live relatively close to sea level, we don't have as much hemoglobin as people who live in the mountains, so it's harder for us to breathe at such elevation.
So that got me thinking, and of course, I turned to research. Now yes, some avian subliminals have affirmations about lungs expanding or air sacs, but i'm going to be talking about another way to make it easier to breathe at such high elevations.

So what is hemoglobin?

Hemoglobin is the protein molecule in red blood cells that carries oxygen from the lungs to the body's tissues and returns carbon dioxide from the tissues back to the lungs.

https://www.medicinenet.com/hemoglobin/article.htm

Birds have a higher count of hemoglobin to help them breathe

First, Barve and his hardy field assistants had to figure how the birds managed to compensate for thinner air. The researchers used mist nets to catch 15 species of birds at elevations ranging from 3,280–10,500 feet (1,000–3,200 meters). At these elevations, air has between 89 percent and 69 percent as much oxygen as at sea level.

They collected a drop of blood from each bird, allowing them to study the birds' hemoglobin—the molecule in red blood cells that carries oxygen from the lungs to the muscles. The blood sample gave them two key measurements: the volume of the blood made up of red blood cells (hematocrit) and the hemoglobin concentration in the blood, measured using a handheld monitor.

"We found the migrant species respond to hypoxia (An absence of enough oxygen in the tissues to sustain bodily functions) just as most humans do when moving from sea level to higher elevations," Barve says. "They do it by increasing their oxygen transport with a greater number of red blood cells."

It sounds like a good idea, since creating more red blood cells means more hemoglobin, which can carry more oxygen. But the strategy has a downside: thicker blood and a higher risk of clots and blocked blood vessels. And it only works for a limited time.

"The amount of oxygen being delivered to the organs actually decreases because the blood is moving more slowly," Barve says, "It's like pumping tomato ketchup instead of blood. It's actually a maladaptive trait to have"—in humans it's a classic cause of an ailment known as chronic mountain sickness. "But it's a response that the body has a lot of control over so that's why it's seen in a lot of organisms."

Like a flatlander going on a ski vacation, the migrant species have apparently found a short-term solution that allows them to survive at high elevation for long enough to complete the nesting season. This quick fix also has the benefit of being reversible, allowing their blood composition to revert to normal when they return to lower elevations.

Meanwhile, Barve found the six resident species had all independently evolved a different technique to increase their oxygen uptake, one that doesn't come with a time limit.

"The resident birds do not increase the number of red blood cells," Barve explains. "Instead, they increase the amount of hemoglobin inside each cell." In essence they make more oxygen-carrying hemoglobin without having to also build all the other parts of a red blood cell. "So they avoid all the bad things that can happen because of thicker blood."

https://www.allaboutbirds.org/news/flying-on-fumes-how-birds-meet-their-oxygen-demands-at-high-altitude/

luckily, the side effects from having a high hemoglobin level are mainly caused by having thicker blood (the result of too many red blood cells) and of i were to put affirmations in a sub for gaining a higher level of hemoglobin, i would put that the amount of hemoglobin inside each cell increases.