Abstract
Understanding the phenomenon of health is crucial for ageing research since there is often an implicit view on what constitutes health and how to measure it. We provide some reflections on how we might better understand and measure health, discuss the basic biological principles of survival, ageing, age-related diseases and eventual death, and end by tying these ideas together to rethink the nature of and implications for healthy ageing. We defend a more positive view on health understood in terms of various phenotypic parameters, such as robustness and resilience, and show how it relates to the aim to support these parameters over time to achieve healthy ageing. Together, these ideas suggest that the most effective strategies for healthy ageing may come from the outside-in by altering those aspects of the environment that prevent robust and resilient phenotypic responses and by supporting those aspects which ensure such responses.