Nairobi, June 13 -- "You've lost some weight. Last time, you looked much bulkier and more built." a visibly concerned Patrick Kondo tells me when we meet for the second time at Nairobi's Parklands Sports Club.

"I lost my father three weeks ago. I haven't been quite myself," I answer.

It has been exactly a month since our paths first crossed. We met during a gruelling outdoor workout session where a group of fitness enthusiasts had made it a tradition to invite strangers for a Saturday morning endurance challenge at the club.

On that day, 62-year-old Kondo was the oldest participant in the group. The youngest was 25.

At 62, the gas and oil consultant is in the shape of his life. With just eight percent body fat, visible abs form a neat...