Grey, at the bottom end of the spectrum, is 50-60% of your maximum heart rate, while red at the top is 92-100%. Before entering the class, I’m fitted with the heart rate monitor, which is a small flashing band that sits comfortably on the upper arm. This syncs up to the screens around the room and shows my heart rate zone, alongside the other 20 people working out in the class with me. Orangetheory also measure something called ‘splat points’, where one splat point is equal to one minute spent in the orange zone and red zone. My personal post-workout breakdown (Liz Connor/PA)Make no mistake, this is a brutal workout class, but it’s clearly effective, as I’m aching for days afterwards.

Source: Irish Examiner April 17, 2019 10:41 UTC