Physical activity has been associated with a variety of cognitive and behavioural changes which, collectively, allow the conclusion that regular exercise contributes to psychological as well as physical health (Folkins & Sime, 1981; Veale, 1987). Thus, while concern has not moved away entirely from whether certain types of exercise have psychological benefits (e.g. Hughes, 1984) considerable attention is now being paid to how these benefits are mediated, and at whom they might best be targeted. Retired and elderly people in particular are being seen increasingly as appropriate candidates for health promotion initiatives which, by increasing levels of physical activity (and, by implication, levels of physical fitness), aim broadly to improve quality of life.

In this context, levels of customary or habitual activity (as distinct from levels of formal exercise participation) are presumed to play an important part, and are now beginning to receive research attention (Shephard & Montelpare, 1988). At present, however, the empirical basis for activitybased health promotion initiatives among elderly people owes much to information derived from younger age groups. Certainly, as regards mental health, relatively little research has directly addressed the assumption that customary physical activity reliably contributes to psychological wellbeing in later life.

The Nottingham Longitudinal Study of Activity and Ageing was set up in 1983 to assess the role of lifestyle and Customary Physical Activity (CPA) in promoting and maintaining mental health and psychological well-being in later life.