It is the common wisdom that retirement from active work speeds the process of decline - and there are all sorts of reasonable explanations as to why this might be the case, but insofar as actual supporting evidence goes you're not going to find much of a consensus. That said, here is an unusual paper amongst those in search of a correlation between retirement and a shorter remaining life span: "Mortality hazard and length of time until death are widely used as health outcome measures and are themselves of fundamental demographic interest. Considerable research has asked whether labor force retirement reduces subsequent health and its mortality measures. Previous studies have reported positive, negative, and null effects of retirement on subsequent longevity and mortality hazard, but inconsistent findings are difficult to resolve because (1) nearly all data confound retirement with unemployment of older workers, and often, (2) endogeneity bias is rarely addressed analytically. To avoid these problems, albeit at loss of generalizability to the entire labor force, I examine data from an exceptional subgroup that is of interest in its own right: U.S. Supreme Court justices of 1801-2006. Using discrete-time event history methods, I estimate retirement effects on mortality hazard and years-left-alive. ... Estimates by all these methods are consistent with the hypothesis that, on average, retirement decreases health, as indicated by elevated mortality hazard and diminished years-left-alive. These findings may apply to other occupational groups characterized by high levels of work autonomy, job satisfaction, and financial security."