Those who are 35 or over and are new to regular exercise should meet with their doctor and arrange a treadmill stress test (TST). This generally involves walking on a treadmill while the electrical activity of the heart is continuously monitored. The treadmill begins slowly, and gradually speeds up until the subject experiences an intense workout.
The test is to check if you heart activity is normal for your age and physical condition. Problems or symptoms which could indicate risk of a heart attack can be spotted and recorded, rather than discovering it the hard way.
Stress tests aren't cheap, but avoiding them is a false economy. A study in Rhode Island of 81 people who had died during recreational exercise showed that 93% had a medical history of heart disease or recognised risk factors, but only four of these people had acted on this knowledge and undergone testing.
In Running Without Fear, Dr Kenneth Cooper points out that for nearly all of us, including those with advanced coronary disease, the health benefits of exercise far outweigh the slight risk of heart attacks or other tragedy during exercise.
There are good ways and bad ways to go about exercise for high-risk individuals. While the specifics of how your exercise program might be tailored differ based on the situation, it could involve a few hours weekly of gentle riding. While this doesn't win races, it lets the rider enjoy most of the benefits and experiences of cycling.