Jumping jacks are an awesome cardiovascular exercise! They’re easy, so anyone can do them. They get the heart rate up pretty fast and are good for increasing cardiovascular health. Not to mention they pack a serious calorie burn! But doing only 100 at a time or 500 jumping jacks spread out throughout the day isn’t really helping you. The key is to sustain an elevated heart rate for an extended amount of time. So here’s a challenge I’ve come up with. Build your endurance.