Yet what if death simply cannot be hacked and longevity will always have a ceiling, no matter what we do? And even if we make it through life with few stressors, this incremental decline sets the maximum life span for humans at somewhere between 120 and 150 years. Measurements such as blood pressure and blood cell counts have a known healthy range, however, Whitson points out, whereas step counts are highly personal. But a long life span is not the same as a long health span, says S. Jay Olshansky, a professor of epidemiology and biostatistics at the University of Illinois at Chicago, who was not involved in the work. In this same vein, Fedichev and his team are not discouraged by their estimates of maximum human life span.