A research group found that higher midlife cardiorespiratory fitness may be associated with a lower risk for stroke hospitalization later in life and that this association is independent of other cardiovascular risk factors, such as hypertension, diabetes and atrial fibrillation.
Stroke is still one of the leading causes of mortality and morbidity worldwide. Several studies have demonstrated a relationship between cardiorespiratory fitness (CRF, how well the body is able to transport oxygen to the muscles during prolonged exercise) and stroke occurrence, however the mechanism behind this relationship has not been established yet, and it might be independent of risk factors such as hypertension, diabetes (DM) and atrial fibrillation (AF).
In this study recently published in Stroke, researchers investigated the association between midlife CRF and stroke risk at a later age and they hypothesized that this association was independent of other stroke risk factors. The study group linked the Cooper Center Longitudinal Study (CCLS) to the Center of Medicare and Medicaid Services (CMS) in order to obtain relevant longitudinal information. 19,815 patients were included in this study between 1999 and 2009, who were eligible for Medicare coverage. CRF was measured by a symptom-limited maximal treadmill exercise test and participants were categorized into three groups based on their results: low, intermediate and high fitness. Traditional stroke risk factors, such as fasting blood glucose and cholesterol, blood pressure and BMI were also measured. 79% of participants were men and 98.3% were Caucasian. The authors observed 808 stroke hospitalizations, with a higher rate in men. Overall, researchers showed that low-fit participants had a dose-dependent higher risk for stroke hospitalization among both men and women. Furthermore, they found that this association was independent of traditional cardiovascular risk factors and also independent of the presence of hypertension, DM and AF. Researchers also found that a 1 MET (metabolic equivalent, measures the intensity of physical activities) higher CRF in midlife was associated with 7% lower risk for stroke hospitalization. They could also prove that the presence of hypertension and AF was also independently associated with a higher risk for stroke, but they were not able to show this association in case of DM.
It seems that there is a dose-dependent inverse association between midlife CRF and stroke risk that is independent of cardiovascular risk factors. These results suggest that increased exercise and physical activity in midlife may be an effective strategy for stroke risk reduction later in life.
Written By: Dr. Fanni R. Eros