Hitting your target heart zone indicates effective boosting of your cardiovascular endurance, as it signifies optimal exercise intensity for improving fitness. Exercising within this range enhances the efficiency of your heart and lungs, while exercising below it may not yield significant gains. Therefore, option A is the correct answer: that you're effectively boosting your cardiovascular endurance.
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Hitting your target heart zone indicates effective boosting of your cardiovascular endurance. This zone helps maximize training efficiency and improves heart and muscle function. Exercising outside this range might mean underexertion or overexertion, both of which can be counterproductive. ;