This paper presents a method for the measurement of changes in health inequality and income-related health inequality over time in a population. For pure health inequality (as measured by the Gini coefficient) and income-related health inequality (as measured by the concentration index), we show how measures derived from longitudinal data can be related to cross section Gini and concentration indices that have been typically reported in the literature to date, along with measures of health mobility inspired by the literature on income mobility. We also show how these measures of mobility can be usefully decomposed into the contributions of different covariates. We apply these methods to investigate the degree of income-related mobility in the GHQ measure of psychological well-being in the first nine waves of the British Household Panel Survey (BHPS). This reveals that dynamics increase the absolute value of the concentration index of GHQ on income by 10%.