Zona Plus is a hand-held device that calibrates grip strength and guides you through two two-minute repetitions of continuous gripping on alternate hands. The instructions recommend doing the exercises five times a week.
The Mayo newsletter indicates that research on handgrip devices is limited, but evidence suggests regular use can result in a ten-point drop in both systolic and diastolic blood pressure. People with blood pressure at or above 180/110 should avoid isometric exercise until their bp is better controlled.
Doing it on your own -- Instead of spending $400 on Zona Plus, a simple spring-loaded device from a sporting goods store may suffice. The newsletter recommends choosing a grip that feels like it requires about 30 percent of your grip strength, and following the Zona Plus exercise routine: two two-minute cycles of continuous gripping on alternate hands. Keep at it at least three times a week for eight to 12 weeks and monitor the impact on your blood pressure.
RESPeRATE analyzes your breathing and creates tones to guide your breathing. Each session lasts 12-15 minutes, and you should use it three or four days a week to achieve the desired effect.