This is a regular verb. It follows the conjugation pattern of the verb falar.
Present:
A Ana respira fundo antes de falar em público.
Ana breathes deeply before speaking in public.
Preterite:
O Miguel finalmente respirou ar fresco lá fora.
Miguel finally breathed fresh air outside.
Conditional:
A Clara respiraria melhor perto do mar.
Clara would breathe better near the sea.