The data shows that magnesium-deficient people use more oxygen during physical activity—their heart rates increased by about 10 beats per minute. “When the volunteers were low in magnesium, they needed more energy and more oxygen to do low-level activities than when they were in adequate-magnesium status,” says physiologist Henry C. Lukaski.
Magnesium enhances the binding of oxygen to haem proteins. There is probably some kind of magnesium pump where oxygen climbs aboard the red cells and magnesium jumps off only to have to jump right back on the red cells again. Red blood cells have a unique shape known as a biconcave disk, which is mission-critical for oxygen transport. Magnesium is important to red blood cell shape and function. The interaction of calcium, magnesium and ATP with membrane structural proteins exerts a significant role in the control of the shape of human red blood cells.
Abnormal magnesium-deprived red blood cells lack the flexibility that allows them to enter tiny capillaries. These nondiscocytes are characterized by a variety of irregularities, including surface bumps or ridges, a cup or basin shape, and altered margins instead of the round shape found in discocytes. When people become ill or physically stressed (more magnesium-deficient), a higher percentage of discocytes transform into the less flexible nondiscocytes.
It should be noted that the body jealously hordes magnesium in the blood and will steal the cells blind to maintain magnesium blood levels and that is why magnesium blood tests tell us nothing about magnesium cell status.