As graying takes hold in Japan, the changes it brings go far deeper than the impact on social welfare and the labor force.

Gym membership among pensioners is surging, for example, even as 20-somethings drop out.

Many of those same young people are losing interest in donating blood, too, yet there is a spike in the need for it among the elderly. Add to this a looming shortage of denture technicians and a grim, lopsided picture emerges.