India, July 16 -- Grief has a way of breaking you, or rebuilding you. For 114-year-old Fauja Singh, it was the unbearable pain of losing his son Kuldeep in 1994 that first pushed him to lace up his shoes for marathons at the age of 89. What began as a way to numb the sorrow, eventually turned into a lifelong love for running, one that carried him to marathon finish lines well into his 100s. Years later, in a different corner of the world, Sandeep Singla felt the same hollow ache after losing his 10-month-old daughter. At 38, he too sought solace in running. Though their journeys began in different times, their stories share the same pulse: of turning grief into strength.

Fauja Singh - who earned the epithet Turbaned Tornado as the world'...