Why aging feels harder after 40
Declining stem cell release and loss of red bone marrow after 30–40 reduce repair capacity, slowing recovery and raising disease risk. Measurement variability and hostile tissue 'terrain' help explain mixed stem-cell therapy results, while exercise, fasting and stress reduction can improve mobilization and point toward routine testing to monitor repair capacity.
Why it mattersFalling red bone marrow and circulating stem cell counts after 40 imply routine stem-cell testing should guide intervention.