Steady-state cardio, in contrast, involves maintaining a consistent, moderate level of exertion over a longer period.

Is 30 minutes of cardio enough? Or, should you be carving ... each week - aka running, cycling, HIIT classes or boxing – plus ...

A trainer breaks down how often to perform cardio and how long your cardio workouts should be for weight loss.

Below are five of the best HIIT treadmill workouts, as recommended by three personal trainers, each capable of giving you an effective and efficient cardio exercise in just 15 to 30 minutes.