To determine maximal heart rate, one can use the formula: 220 minus their age. This estimate provides a general guideline for assessing aerobic exercise intensity. For a more accurate measurement, individuals can conduct a stress test under medical supervision, where heart rate response is monitored during increasing exercise intensity. Knowing one's maximal heart rate is crucial for establishing personalized training zones, allowing for effective cardiovascular workouts and ensuring that individuals are training at appropriate intensities for their fitness goals.