It seems there will be a good market for fresh blood (or blood fractions) from young athletes 
Exercise strengthens both the body and the mind, and researchers are uncovering the molecular messengers that make the connection. The messengers can also be transferred from an active mouse to a sedentary one.
Exercise has big benefits for the brain, but the exact reasons why have been mysterious. Now, new studies suggest that exercised muscles release brain-boosting substances into the blood — and at least in lab animals, that boost can be transferred from one individual to another via an injection of those substances.
Previously, common explanations for why regular physical activity is good for the brain pointed to better blood flow, less stress and a stronger heart. But those ideas didn’t fully explain how movement directly affected neurons.
Clues are emerging from animal research. In a study published in October in the journal Brain Research, one group of young adult mice ran freely on wheels for four weeks while others stayed sedentary. Scientists then isolated extracellular vesicles — molecular “packages” that carry proteins and genetic material — from the runners’ blood and injected them into the sedentary mice.
After getting these injections twice a week for four weeks, these treated sedentary mice grew about 50% more new brain cells in a memory-related region called the hippocampus, compared with untreated sedentary mice. Most of the new cells developed into mature neurons, a process known as neurogenesis. (For humans, there’s ongoing debate around whether neurogenesis occurs in meaningful amounts in the adult brain.)