A heart rate monitor is a must at Orangetheory, and this Scosche Rhythm+ Heart Rate Monitor Armband ($80) is a great option. Orangetheory studios also sell three different heart monitors that were designed specifically for the class. "Wearing one of Orangetheory's OTBeat heart rate monitors isn't mandatory, but it's strongly urged and recommended to get the most out of our workout because it's a crucial part of what makes Orangetheory so special," Alicia said.