Strenuous daily exercise actually increased the risk of coronary heart disease, venous thromboembolism, and cerebrovascular disease, compared with moderate physical activity, according to new data from the Million Women Study.
At baseline, the 1.1 million women who participated in the study were 55.9 years old on average, with a mean body mass index of 26 kg/m2. Over the next 9 years, those reporting moderate activity had significantly lower risks of all three conditions than did inactive women, according to a study published online Feb. 16 in Circulation [doi:10.1161/CIRCULATIONAHA.114.010296].
However, women who undertook daily strenuous activity had a 15% increase in their risk of coronary heart disease, a 25% increase in cerebrovascular disease risk, and a 29% increase in venous thromboembolism (VTE) risk, compared with those who exercised strenuously two to three times a week, judging from the findings of Cox regression models that controlled for BMI, smoking, and alcohol consumption.
“Among active women, there was little evidence of progressive reductions in risk with more frequent activity, and even an increase in risk for CHD, cerebrovascular disease, and VTE in the most active group,” wrote Dr. Miranda E. G. Armstrong of the University of Oxford, England, and colleagues.
The study was supported by the UK Medical Research Council, Cancer Research UK, and the BHF Centre of Research Excellence. There were no other conflicts of interest declared.