A typical interpretation of stress testing assumes that all subjects who take the test are cardiology patients. However, its prognostic value in apparently healthy, asymptomatic subjects with a low pretest probability of heart disease is rarely considered.
Burden testing from diagnosis to prevention
Exercise testing involves a test on a indoor cycle or a treadmill, during which blood pressure and ECG are measured. The exercise load is gradually increased according to a predefined protocol until maximum exercise capacity is reached, at which point the subject is no longer able to continue and the test is discontinued. This type of testing is most commonly used to diagnose cardiac artery disease, where we look for changes in the ECG that indicate ischaemia of the heart muscle or partial blockage of blood vessels.
It is also used to diagnose chronotropic insufficiency, which is the inability of the heart to increase its rate during exercise. In both cases, it is for the management of cardiac patients and not for preventive tests. However, other important information can be obtained during testing, which is crucial from the point of view of longevity.
The drop in heart rate after exercise is due to reactivation of the parasympathetic nervous system.
Abnormal drops in heart rate were associated with a fourfold increase in mortality.
Heart rate after exercise as a predictor of longevity
In a six-year study of 2,428 adults with no history of heart failure, coronary artery disease or pacemaker insertion, researchers investigated whether a slowed heart rate decline after the test is a significant predictor of risk of premature mortality. Decreased vagal activity is known to increase the risk of death. During exercise, heart rate increases due to a reduction in vagal tone, whereas the fall in heart rate after exercise is due to reactivation of the vagus.
Subjects underwent exercise stress testing to maximal effort, and a drop in heart rate was defined as a decrease in heart rate from maximal to that after 1 minute of rest. An abnormal value was defined as a reduction of 12 or fewer beats per minute.
Increased mortality due to insufficient heart rate recovery
During the observation period, 213 deaths from various causes were recorded. A total of 639 subjects had abnormal heart rate drops, which were associated with a fourfold increase in mortality. Even when additional factors were taken into account, the association remained significant, with a mortality rate twice as high.
Action can improve parasympathetic nervous system function
Testing reveals parasympathetic nerve function, which is an important marker of longevity. A slowed heart rate fall in the first minute after exercise is a strong predictor of mortality, independent of exercise training, the presence of heart muscle defects or rhythm disturbances during the test. However, with appropriate measures and lifestyle adjustments, we can influence this marker and thus reduce the risk of premature death.
Link to the study:
But with the right measures and lifestyle adjustments, we can reduce the risk of premature death.
