I've read a few articles that have said the same thing and I think that it is true. I don't think there is any way to get a more accurate reading about shaking. I tried looking up shaking, shivering and trembling and the best thing I got was the extra calories you burn trembling during sex, which a thought was a lot of hooey. I would not worry about counting the calories for the shaking, I was just consider it an extra bonus added to whatever other activities you participate in.
The side effects of allergy medications keep some people from using them. Natural remedies can be a great alternative, but some are more effective than others.