This dissertation consists of three essays. The first essay studies how health risk affects individuals' economic decisions due to changes in productivity, required medical expenditures, available time and survival probabilities implied by changes in health status. It assesses the role of these four channels in determining labour supply, asset accumulation and welfare using a life-cycle model calibrated to the U.S. economy. I find that all channels and the interactions between them have large implications for the macroeconomic variables studied. Health has larger effects for the non-college than college educated, explaining a significant fraction of the difference in labour supply, degree of reliance on government transfers and asset accumu...