The nature versus nurture debate is one of the oldest issues in the study of longevity, health and successful aging. We present a 97-year-old man (I.K.) as an example of the effects of habitual exercise on the aging process. Extensive assessments included medical examinations, interviews, musculoskeletal structure, performance characteristics, cognitive function and gut microbiota composition. I.K. suffers from iatrogenic hypogonadism, prostate cancer, hypothyroidism and a history of deep popliteal thrombosis. Notwithstanding, he cycles up to 5,000 km a year and participates in competitive sports. His musculoskeletal properties, athletic performance, cognitive function and gut microbiota are outstanding. Some traits even exceed those seen in middle-aged men. His long-term physically and intellectually active lifestyles combined with extensive social interactions have most likely contributed to his exercise capacity, despite his medical history.