Breakdown of Se hidrata mucho, de ahí que su metabolismo funcione muy bien.
de
from / of
mucho
many / a lot
su
his/her/its/their/your (formal)
muy
very
Questions & Answers about Se hidrata mucho, de ahí que su metabolismo funcione muy bien.
Why is funcione in the subjunctive here if his metabolism actually working well is a stated fact?
The phrase de ahí que (hence / which is why) is a special connector that always triggers the subjunctive, even when stating known facts or actual outcomes. Because the cause (se hidrata) is in the present tense, we use the present subjunctive (funcione) for the consequence.
Could I use por eso instead of de ahí que to mean the same thing?
Yes, but it changes the grammar. While de ahí que requires the subjunctive, por eso (that's why / therefore) requires the indicative. If you swap them, the sentence becomes: Se hidrata mucho, por eso su metabolismo funciona muy bien. Note that de ahí que sounds slightly more formal or educated than por eso.
Why use the reflexive pronoun se in se hidrata?
How would this sentence change if we were talking about his habits in the past?