Is a low heart rate a cause of concern if I exercise rigorously often?

Well, it depends. An average HR close to 45 may be the norm for someone like Usain Bolt but for the vast majority of us who are not professional long-distance runners (or athletes of any sort) it may be a tad low. Therefore you need a one-to-one consult to look at individual factors such as your age, other medications or coexisting conditions, family history and fitness levels. Though the vast majority of causes for "fainting"is benign, certainly low heartrate combined with low BP and symptoms will need to be looked at further.

From a biomedical perspective, a stroke occurs when blood supply to the brain is interrupted, causing brain cells to lose their function thus leading to the signs and symptoms commonly observed. There are two main types of stroke: Ischaemic stroke occurs due to blockage of blood vessel, limiting blood flow to the brain. It is the most common, accounting for 74% of stroke in Singapore. Haemorrhagic stroke occurs due to rupture of blood vessel, causing bleeding into the brain. This makes up 24% of stroke in Singapore.