Breakdown of Se a pressão estiver alta, a médica vai medir de novo amanhã.
estar
to be
amanhã
tomorrow
ir
to go (future auxiliary)
se
if
Questions & Answers about Se a pressão estiver alta, a médica vai medir de novo amanhã.
Why is it Se and not Se a pressão está alta?
Because Se introduces a condition (if). In Portuguese, when you’re talking about a possible/uncertain condition in the future, it’s very common to use the future subjunctive: Se + (future subjunctive).
So Se a pressão estiver alta = If the blood pressure is (found to be) high (in that future situation).
Se a pressão está alta sounds more like a present-time statement or a general fact (and in Brazil it can also appear in casual speech), but the “textbook/standard” choice for a future condition is estiver.
What tense/mood is estiver?
Estiver is the future subjunctive of the verb estar (to be).
Conjugation (estar, future subjunctive):
It’s triggered very often after se when the condition refers to the future.
Why is it estar (estiver) and not ser?