First off, please understand that I'm not blaming vaping. I have many "bad" habits, and don't exactly live a lifestyle that is the opitamy of health. I'm just curious. Lately im showing some signs on and off of nic o.d., I think. Increased heart rate, tingling in back of head, extremely restless. I just don't see how this is possible. I don't feel my nic intake is even close to "high". I know it varies for everyone but? I wound say in average I go thru 4-6 ml of 12mg on mouth to lung tanks, and 6-10 ml of 3 or 4mg on direct lung hit tanks. Just doesn't seem like that much to me?