Caution Warning for certain health conditions. Who should avoid use: If you wear a Pacemaker or have a full metal limb as well as if you suffer from low blood pressure, had recent surgery within two weeks, you have stitches, heart problems, internal medical devices. If you are severely obese and haven't recently had a physical exam by your primary physician within 6 months. If you are pregnant or breastfeeding or if you are actively bleeding or on your menstruation cycle. You are encouraged to get approval to participate from your primary care physician before starting any health or fitness program for your safety.