Two studies from Scandinavia confirm: Cycling protects against cardiovascular diseases: What is important is not so much the duration of the sporting activity, but the change from inactivity to activity. How long you cycle is of secondary importance.
In a first study, the Danish scientists analyzed the data of around 20,000 Swedish men and women who were in their early 40s and were examined twice during a 10-year follow-up period. Compared to study participants who traveled to work by public transport or car, cyclists were less likely to be obese at baseline, less likely to have high blood pressure and lower cholesterol. They also suffered less from prediabetes or diabetes. After 10 years it was found that cyclists had a 39% lower risk of obesity (39%), high blood pressure (11%), high cholesterol (20%) and diabetes (18%) than non-cyclists.
A second study also showed the reduced risk of cardiovascular diseases. She examined the cardioprotective effect of cycling to work and during leisure. The study authors showed that those who cycled to work every day or cycled regularly in their free time were 11 and 18% less likely to develop coronary artery disease than non-cyclists.
The main effect comes from switching from inactivity to exercise, after which there is hardly any increase in cardiovascular protection. You can find the studies here and here.