My two thoughts here, I vape about 20 mil of juice a day. That seems like alot but the nature of these more fancy tanks these days, they seem to drink alot of juice. I use an aromamizer plus atomizer, which is a big fancy tank that you build your own coils on.
I vape 3 mg of nic levels which is very, very low. Id get it even lower if I could but no one seems to make juice less than 3 mg so, thats where Im at.
I have never experienced what people are talking about here, hiccups? Thats weird!! Shaking? Thats also weird!!
Only thing I experienced was what you might called nausea, or a slight dizziness. Think the same feeling you get if you spin around in a circle two or three times. Nothing extreme, just slight (thats why I said, spin only twice, not 10 times

. Usually I only get this when handling the liquid directly, which, if you are a coil builder, is inevitable. The oil gets onto your hands and what people do not always know or remember is, your skin absorbs nicotine as well. Nicotine is very soluable. It only takes 1 drop of pure nicotine on your skin to get you VERY sick and kill you (thankfully, we dont deal with pure nicotine as consumers). Nicotine absorbs into your blood VERY quickly through the lungs. You dont need to take a deep inhale off an ecig and hold it for a second or two like a traditional cigarette for the nicotine to be absorbed. With an ecig, you literally can inhale as much as you feel comfortable inhaling and IMMEDIATELY exhale without taking any more air in or holding your breath for a few seconds and 97% of the nicotine will be absorbed into the blood stream by that point. With regular cigarettes, it works much differently. There are still studies going on attempting to figure out exactly what happening with a regular cigarette that takes it so much longer to absorb into the blood stream.
Understand that a typical single cigarette has about 8-20 mg of nicotine per cigarette. Your body will absorb just under of 1 mg of that 8-20 mg of nicotine in that cigarette with the average nicotine level of about 12 mg per cigarette.
The nicotine levels in eliquid are measured per milliliter. What does this mean? If you are a pack a day smoker start with about 12 mg of nicotine level in your juice (some suggest starting at 18 mg but given the quality of atomizers these days, I think 12 is about right). If you are vaping 5 ml of juice, that means you will be taking in 60 mg of nicotine a day. A pack of cigarettes, by comparison will be about 12 mg * 20 cigarettes or about 240 mg a day.
You might be thinking, wait, Ill be taking in less nicotine than regular cigarettes. That would be correct. However, what is also happening is, since there is less of the other products in an ecig, you are also absorbing much more nicotine via vaping that you do with cigarettes. The particulates in a cigarette are MUCH smaller than the particulates in an ecig. This means that the particulates absorb into the blood stream more effectively and do not stick to the lining in your lungs.
I hope this helps enlighten a little bit, the science is still very new on this stuff...