Final answer:
Increasing the frequency of fitness training sessions is a common practice. Exercising at or above the ventilatory threshold can help improve cardiovascular endurance and increase fitness levels.
Step-by-step explanation:
Increasing the frequency of fitness training sessions is a common practice to improve fitness. When possible, these sessions are done within or even possibly above the ventilatory threshold. The ventilatory threshold is the point at which the body begins to rely more on anaerobic metabolism to produce energy. Exercising at or above the ventilatory threshold can help improve cardiovascular endurance and increase fitness levels.