Riding your bike on traffic-congested streets may be damaging to your heart. A study by the British Heart Foundation (BHF) showed microscopic particles carried in diesel fumes can cause damage to blood vessels and impair their function, contributing to the development of heart disease. However, the BHF added that cardiovascular benefits derived from regular exercise on a bike still outweighed the risk of pollution and recommend that when cycling outdoors one should stick to paths away from busy roads.