Background: Evidence on the association between social support and leisure time physical activity (LTPA) is scarce and mostly based on
cross-sectional data with different types of social support collapsed into a single index. The aim of this study was to investigate whether
social support from the closest person was associated with LTPA. Methods: Prospective cohort study of 5395 adults (mean age 55.7 years,
3864 men) participating in the British Whitehall II study. Confiding/emotional support and practical support were assessed at baseline in
1997–99 using the Close Persons Questionnaire. LTPA was assessed at baseline and follow-up in (2002–04). Baseline covariates included
socio-demographics, self-rated health, long-standing illnesses, physical functioning and common mental disorders. Results: Among participants
who reported recommended levels of LTPA at baseline, those who experienced high confiding/emotional support were more likely to
report recommended levels of LTPA at follow-up [odds ratio (OR): 1.39, 95% confidence interval (CI): 1.12–1.70 in a model adjusted for
baseline covariates]. Among those participants who did not meet the recommended target of LTPA at baseline, high confiding/emotional
support was not associated with improvement in activity levels. High practical support was associated with both maintaining (OR: 1.34, 95%
CI: 1.10–1.63) and improving (OR: 1.25, 95% CI: 1.02–1.53) LTPA levels. Conclusion: These findings suggest that emotional and practical
support from the closest person may help the individual to maintain the recommended level of LTPA. Practical support also predicted a
change towards a more active lifestyle.