She's 80 with the fitness level of a 60-year-old. Her routine is surprisingly simple.

She's 80 with the fitness level of a 60-year-old. Her routine is surprisingly simple.

Linda Kelly built elite fitness over the years by staying consistent.Nathaniel Wilder for BI"I have always seen myself as a very ordinary person with no real athletic ability," said Linda Kelly.Still, at 80, she has completed multiple half-marathons and routinely hikes, bikes, and runs around her part-time home in Anchorage, Alaska.Kelly is as fit as someone decades earlier, with the lab results to prove it. Her son, cardiologist Dr. Jake Kelly,…