A fit cyclist who had a heart attack found success in a new type of cardiac rehab program based on high-intensity interval training (HIIT), allowing him to regain his fitness level and return to riding at full intensity. 

Reverend Carl Matthei, a fit cyclist who cycled regularly and ate a healthy diet, never thought he could be at risk of heart disease. However, at age 47, he experienced chest discomfort during a ride with friends and was rushed to the hospital. Despite having none of the usual risk factors associated with heart disease, he was diagnosed with aggressive coronary disease and had a heart attack. Following the heart attack, he participated in a new type of cardiac rehab program based on high-intensity interval training (HIIT) instead of traditional slow spinning on a stationary exercise bike. The HIIT program was more effective and helped him safely regain his fitness level. One year after the heart attack, he was allowed to ride at full intensity again and his cycling and general health and fitness returned to the level before the heart attack. He encourages others to pay attention to any symptoms they experience and seek medical help if necessary. 

Source: https://www.menshealth.com/health/a38592388/young-heart-attack-recovery-hiit-carl-matthei/