BINGO!!
Like a car, without fuel it won't go very far and neither will you.....Never mind those drinks, EAT real food!

rops:
I would have to agree with the low blood sugar comment, as this would be the most common cause of "shakes" that are noticeable by us. However, a lot different factors could contribute to this and although you mentioned smoking, I'm not going to focus on it (mainly because you probably know it's not a healthy habit).
Although I am by no means a doctor, nutritionist, or expert dietitian, I have worked with IFBB professionals, powerlifters, nutritionists, and other health industry guru's on understanding the ins and outs of how our bodies react with certain foods, and what works best for each particular case.
In order to really begin narrowing down where the problem truly lies hopefully you can answer some questions for me, and I'll respond as soon as I can to hopefully get you back on the right track to feeling good, and not having to worry about your health :dblthumb2:
What is your diet like (how many meals do you have in a day, what is a typical meal for you (food types and portions), how much and what kind of liquid do you drink)?
Does your diet change on days that you perform details, and if so, why?
How long is it before the "middle" of your typical detail when you notice the shakes?
Besides the smoking, do you have any other history of pre-exisiting medical and/or diet issues that you feel comfortable speaking of?
What are the ambient conditions when you typically perform a detail and notice the shakes?
I know it's a lot to digest, but this will help steer us in the right direction. Please keep in mind that any recommendation that is made can be what works for that person but every single person's body will react a different way to different nutrients depending on genetic, physical, and environmental factors.
I can give you a general run down of what I would try first, but if you're willing to answer the above questions that would be best.
Hope to hear from the OP soon.