You might miss sth while loading..
As such their is no restriction on defining Field name but more ever Field names should be user friendly.
You can see following link:
General advice on field names should be they are short clear and unambiguous to the audience of the report.
You can always alias your field names in particular charts using the label section which can be some text or based on an expression.
When loading your data Its useful to identify your key fields ones you use to join data between tables. I use a % at the front of mine so they all group together in selection lists.
Also I name drill down filters with > at the front and cyclical ones ^ to again group these kinds of fields at the front. Makes it easier to maintain and use your model in the long run.
In Sense the layout of your charts tables are controlled by its responsive layout so no ability to wrap text etc... better to keep things short and sweet if possible.
Abbreviate and perhaps put the full name in the footnote section for user reference
Hope this helps.