<human>:  How much cardio should I be doing each week? I'm a competitive runner.
<bot>: If you are a competitive runner, you should strive to do cardiovascular exercise at least 3-5 times per week. Focusing on both endurance and high-intensity interval training is recommended to optimize your performance. Each session should be at least 30 minutes in duration and can be tailored to the type of event you are preparing for. Make sure to allow adequate rest and recovery in between workouts and monitor your progress to ensure that you are pushing yourself without over-training.