PHYSICAL-ACTIVITY, PHYSICAL-FITNESS, BLOOD-PRESSURE AND FIBRINOGEN INTHE NORTHERN-IRELAND HEALTH AND ACTIVITY SURVEY

Study objective - To investigate the relationship between physical act ivity,physical fitness, blood pressure, and fibrinogen. Design - This was a cross sectional population study using a two stage probability s ample Setting - Northern Ireland. Participants - A sample of 1600 subj ects aged 16-74 years from the population of Northern Ireland. Main ou tcome measures - Physical activity profile from computer assisted inte rview using the Allied Dunbar national fitness survey scales. Physical fitness using estimation of VO2 max by extrapolation from submaximal oxygen uptake while walking on a motor driven treadmill. Systolic and diastolic blood pressure measured with a Hawksley random zero sphygmom anometer. Measurement of fibrinogen using the Clauss method. Main Resu lts - There were significant relationships between both current and pa st activity and blood pressure. These were of a magnitude that would h ave been clinically significant, but for the fact that, with the excep tion of the relationship between habitual activity and diastolic press ure (p = 0.03) and past activity and systolic pressure (p = 0.03) in m en, they were not sustained after adjustment for the effect of age usi ng analysis of variance. After adjustment for other potentially confou nding factors using multiple regression, there was an inverse relation ship between systolic blood pressure and past activity in men, so that those with a life-time of participation compared with a life-time of inactivity had a lower systolic blood pressure of 6 mmHg (p<0.05). The re was a highly significant (p<0.001) inverse association between both systolic and diastolic blood pressure and physical fitness (VO2 max) which was not sustained after adjustment for possible confounding fact ors. There were relationships between fibrinogen and highest recorded activity (p<0.001), habitual activity (p<0.01), and past activity (p<0 .01) in men but no significant relationship in women. The relationship between fibrinogen and activity was no longer sustained after adjustm ent for possible confounding factors. There was a highly significant ( p<0.001) inverse relationship with physical fitness using VO2 max. Thi s relationship was sustained after adjustment for possible confounding factors in both men (p<0.05) and women (p<0.001). Conclusions - There was a relationship between physical activity, physical fitness, and b lood pressure but the relationship was greatly influenced by age. A re duction of 6 mmHg in systolic blood pressure associated with past acti vity is of clinical significance and supports the hypothesis that phys ical activity is of benefit in reducing cardiovascular risk. There was a lower level of fibrinogen in those who were most active but this re lationship was not significant after adjustment for possible confoundi ng factors. There was also lower level of fibrinogen those who were mo st fit (VO2 max) and this relationship persisted even after adjustment for possible confounding factors.