Steps in Healthspan makes it inaccurate. My main issue is that its to measure how active your lifestyle is, but you can be very active with multiple cardio activities with low steps and would get a high whoop age, and the weight of steps is much larger that HR zones form my experience. While you can do half of the cardio activities you do but instead of swimming, bike etc you do it as running and it will count toward steps and give you a much lower age. So you can be more active but because you do non arm swinging activities you will get a higher age.