Not much there by way of symptoms but there's this:
"During sauna-based detoxification, and during heavy exercise, fluorine appears to mobilize from body stores. In sufficient quantities, such dumping can cause the symptoms of acute fluorine poisoning and have serious consequences. The fluorine re-entering the circulation can cause acidity (possibly hydrofluoric acid or related compound)."
wikipedia lists symptoms of fluorine poisoning.
When poisoned by fluoride, gastrointestinal signs predominate.
Widening of QRS