The study found that healthy people were very resilient to stresses, while people who had chronic diseases and an elevated risk of mortality were less resilient. The recovery time also grew longer with age – two weeks for a healthy 40-year-old to six weeks for an 80-year-old. This finding from blood test parameters was compared to and confirmed by physical activity levels recorded by wearable devices. By extrapolating this trend out, the team found that people will completely lose their ability to recover – that is, their resilience – by the age of 120–150, even if they are otherwise healthy and not suffering from major disease. “This work indicates that the apparent human lifespan limit is not likely to be improved by therapies aimed against specific chronic diseases or frailty syndrome,” the authors write in their paper.