[Naufal the B. S. (OP)]

what kind of food maybe... that can close this thread  ?
or another trick tat can put some more oxygen into my blood ?
or another trick tat can make my concentration ″recovered″ ?

thanks before

[Bored chemist]

Like most things an excess of oxygen is poisonous.

[Kryptid]

Oxygen is held in the blood mostly by iron complexes in the red blood cells (hemoglobin). Eating more iron-containing foods, however, won't make your blood better at holding oxygen (unless you are anemic and therefore actually need the iron). The human body is good at regulating what it needs and would prefer to keep things at a certain balanced level. It has some capability to resist excess iron for this reason. Eating enough iron to overcome that filter could be hazardous, though.

I'm skeptical that any foods would help much with oxygen in your blood.

[CliffordK]

There is a practice called "Blood Doping".

Anything that will increase the Red Blood Cells (erythrocytes) and the Hemoglobin will increase the oxygen carrying capacity of the blood.

If you are doing sports, there are several illegal ways of doing "blood doping", including medications, and having your own blood removed from the body, stored for a few weeks, then re-injected.

However, it is still currently legal to do high altitude training.  Do your training at the highest elevation you can get to.  Your body will compensate to the lower oxygen levels at the high elevations by increasing the RBCs.  Then when you return to lower elevations your blood will have more oxygen carrying capacity.

Serious medical conditions such as Carbon Monoxide Poisoning can be treated with concentrated oxygen, and even a hyperbaric chamber if the condition is serious enough.

[zyper]

There are two body systems involved here, the respiratory and circulatory. So you need to keep those two systems in topnotch condition. Make sure you're not anemic. It's a good idea to see your doctor if you're feeling fatigued. When you do exercise include some kind of aerobic exercise to improve your heart's pumping action, so that the hemoglobin can pick up the waste products and CO2 and deliver fresh SPAM to your cells.