I keep my pressure between 3 and 4. The frequency HZ i use is different ones all the time. I start out @ 10 and then up to 15 , then sometimes i go all the way to 25. The only problem with going that high is , it itches the heck out of me where the vest is. I do feel the vest is a help to me ( or i wouldnt do it at all) but i have to admit it annoys me sometimes. I have the old model vest ( the real big heavy machine)