Levels of Physical Activity, Physical Fitness and their Relationship in the Northern Ireland Health and Activity Survey

The aim of the study was to describe the physical activity and physical fitness profile of the population of Northern Ireland and to explore the relationship between physical activity and physical fitness. This was a cross sectional population study using a two stage probability sample of the adult population of Northern Ireland (aged 16+). The main outcome measures were physical activity profile based on computer assisted interview. Physical fitness using estimation of VO2max by extrapolation from submaximal oxygen uptake while walking on a motor driven treadmill. We found that males were more vigorously active than females (M 21%:F 6%) with a steep gradient of decreasing activity with age: 49% (M 52%:F 46%) were regularly active up to at least moderate intensity. Males (mean predicted VO2max 44.4 mls/kg/min; 16-74 years) were fitter than females (mean predicted VO2max 34.0 mls/kg/min; 16-74 years) and while there was a decline in predicted VO2max with age, there was wide variation within each age category. There was no statistically significant relationship between current or past activity and fitness after adjustment for possible confounding factors, with the exception of a relationship between fitness and activity in males so that the difference between no activity and habitual vigorous activity in predicted VO2max was 4.4mls/kg/min (10.1%).