Dr.rer physiol. title in Germany I am a future PhD student here in Germany and I am worried about whether the PhD German title (Dr.rer.physiol.) will be accepted internationally in general and in Germany in particular. In fact here in Germany there are many different titles that is possible to get after the PhD, the most common is Dr.rer.nat (literally, Doctor in natural sciences), but then You can be also Dr.rer.med, or Dr.rer.phil, Dr.ing. or whatever (https://en.wikipedia.org/wiki/List_of_doctoral_degrees_awarded_by_country).
But my question is; which is the relevance of one or another title?
Could be really make a difference get one instead of another?
I am really wondering about because there are not really clear info on this topic and I would like to know what is better for my future career!

Thanks a lot
I am looking forward to any answer!
Marta
The part of the degree after the "Dr." indicates the discipline in which you obtained your degree. Depending on potential future employers, it can be an important signal about your technical qualification. Especially university department can be quite selective in choosing only candidates with the "right" type of degree for post-doc or faculty appointments. It may also play a role in some industry positions, but probably to a lower extent. 

Many university departments offer only a single type of degree - engineering departments the Dr.-Ing., natural science and mathematics departments the Dr. rer. nat., and so on. Sometimes there's multiple degree options in one department - in that case mostly the area that your supervisor is supposed to work in will determine which degree you can be awarded.

It seems the specific degree you are looking at, the "Dr. rer. physiol.", is a degree from a medical department. Doctoral degrees in medicine, traditionally the Dr. med., are a special case in the German academic community since they typically require much less work (a year) compared to other fields (three to six years). Therefore, graduates with a Dr.med. degree are often not perceived as fully qualified scientists, especially in international contexts (see e.g. the German Wikipedia article on Dr.med. degrees) for a short discussion of this point). On the other hand, many people looking for medical treatment would see any practicing medical doctor who does not have the Dr. med. degree as not fully qualified. And as far as I am aware obtaining the Dr. med. degree also requires that you get the full training as a practicing medical doctor, so it's not suitable for example for scientists with a biology or chemistry background who just want to do research in medicine.

In order to cope with this dilemma, the medical departments in Germany have introduced a range of additional doctoral degrees, among them the Dr. rer. physiol. (see www.zeit.de/2009/43/C-Doktor-Med for an article on that). The common feature of these degrees is that they don't qualify you as a practicing medical doctor, but on the other hand they hopefully will require more research work than the Dr. med. degree, and in this way qualify you better as a scientist. Nevertheless, if there is the alternative to get the Dr. rer. nat., it's maybe a safer way career-wise to go for this more traditional natural science degree.