What condition must be true regarding a driver certified with cardiovascular disease?

When a driver is certified with cardiovascular disease, it is essential that they exhibit no residual symptoms from their condition. This requirement ensures that the driver is stable and not at risk for sudden incapacitation due to their cardiovascular issues while operating a commercial vehicle. Residual symptoms, such as chest pain, shortness of breath, or fatigue, can significantly impair a driver's ability to safely navigate and operate their vehicle, posing a danger not only to themselves but also to others on the road.

The other options do not necessarily reflect the critical aspects of driving safety and overall cardiovascular health. For instance, a driver may be on prescription medication, which can be managed appropriately, and still maintain a safe driving status. Likewise, while normal blood pressure at rest is crucial for overall health, it alone does not guarantee that the driver is free from other dangerous symptoms. Lastly, while a regular exercise routine is beneficial for cardiovascular health, it is not a definitive factor for certification in the context of commercial driving. Hence, the lack of residual symptoms stands out as the key condition for ensuring a driver's fitness to operate a commercial vehicle safely.