A retired doctor started exercising seriously at 50. At 90, he climbed Kilimanjaro.

Dr. Art Ulene, during his epic Kilimanjaro climb. Courtesy of Dean Cardinale, World Wide Trekking Dr. Art Ulene climbed Mount Kilimanjaro and reached the top on his 90th birthday. The nonagenarian completed the challenge to inspire older people to reach their full potential. He shared his longevity secrets with Business Insider. Soon after Dr. Art Ulene reached the top of Kilimanjaro on his 90th birthday, he applied to Guinness World Records to check whether he was the oldest person to…