Make sure you are not drinking alcohol, avoid stimulates, and hydrate. If you are doing all that and still not going to 100 might be defective. I wear my watch pretty loose and still get great results. I thought mine was not working at first but turns out was drinking to much coffee and alcohol for my body to actually get to 100. Also make sure you are getting minimum 8 hours sleep. When you are at zero can take 10 - 12 to get up to 100 then you will not be starting from zero each night.