Excessive physical activity may not be as beneficial as moderate physical activity for vascular disease risk in UK women
While physical activity has been associated with reduced risk of vascular disease there is limited evidence about the effects of the frequency and duration of various activities on the incidence of particular types of vascular disease. Specifically, risk relationships are still unclear for pathological subtypes of stroke and venous thromboembolism.
METHODS:
In 1998, on average, 1.1 million women without prior vascular disease answered questions about the frequency of physical activity and many other personal factors. Three years later, they were asked about hours spent doing specific activities (walking, cycling, gardening, housework) which was used to estimate excess MET-hours expended per week. Women were followed by record linkage to the National Health Service cause-specific hospital admissions and death records. Cox regression was used to calculate adjusted relative risks for first vascular events in relation to physical activity.
RESULTS:
During an average of 9 years follow-up (after excluding the first 4 years of follow-up because of possible reverse causation bias), 49 115 women had a first coronary heart disease event (CHD), 17 822 had a first cerebrovascular event, and 14 549 had a first venous thromboembolic event (VTE). Moderate physical activity was associated with significant reductions in the risk of these conditions. However, increased frequency or duration of various activities usually did not provide additional benefit and sometimes the groups with highest frequency of activity had higher risks of VTE and cerebrovascular disease than the moderately active. Risks did not differ significantly for sub-types of cerebrovascular (haemorrhagic or ischemic, P = 0.4 for any physical activity) or of VTE (with or without pulmonary embolism, P = 0.9 for any physical activity).
CONCLUSIONS:
Moderate physical activity is associated with a reduced risk of developing CHD, VTE and cerebrovascular disease in UK women. The most active groups did not experience additional benefit and sometimes had higher risk of VTE and cerebrovascular disease than the moderately active.