Learn Hardcore Portuguese (Portugal): À noite, eu respiro fundo três vezes para relaxar. - At night, I breathe deeply three times to relax.

À noite – very common, neutral: in the evening / at night
- À noite, eu leio. – I read at night.
De noite – also at night, sometimes with a slight flavour of “during the nighttime (as opposed to daytime)”.
- Ela só trabalha de noite. – She only works at night (as a night shift).

In your sentence, you could also say:

De noite, eu respiro fundo três vezes para relaxar.

It would sound natural; the meaning is essentially the same.

Is the comma after À noite necessary?

Both are acceptable:

À noite, eu respiro fundo três vezes para relaxar.
À noite eu respiro fundo três vezes para relaxar.

In Portuguese, a short time expression at the beginning (like À noite, De manhã, À tarde) may take a comma, but it’s not obligatory. The comma simply marks a slight pause and can make the sentence a bit clearer in writing, but leaving it out is not wrong here.

Do I have to say eu, or can I just say À noite, respiro fundo…?

You can drop eu; in fact, that’s very natural in Portuguese:

À noite, respiro fundo três vezes para relaxar.

Portuguese is a pro‑drop language: the verb ending (respiro) already tells us the subject is eu.

Including eu is fine, but it can:

add emphasis: À noite, eu respiro fundo… (I, as opposed to others)
or simply sound a bit more explicit / careful.

In relaxed, everyday speech you’ll very often hear À noite, respiro fundo… without eu.

What tense is respiro, and why is the present tense used here?

Respiro is the present indicative (presente do indicativo) of respirar.

In Portuguese, this tense is regularly used to express habits and routines, just like English “I breathe…” in “Every night I breathe deeply three times”.

So:

Eu respiro fundo três vezes = I (usually / habitually) breathe deeply three times.

You do not need a special “habitual” form. The simple present covers:

now: Agora respiro fundo. – Now I’m breathing deeply.
routines: Todos os dias respiro fundo. – Every day I breathe deeply.

If you wanted to stress the idea of habit even more, you could say:

À noite, costumo respirar fundo três vezes para relaxar. – At night, I usually breathe deeply three times to relax.

Why is it respiro fundo and not respiro profundamente? What is fundo doing here?

Fundo normally means deep (or bottom), but after certain verbs it works as an adverb meaning deeply:

respirar fundo – to breathe deeply
suspirar fundo – to sigh deeply
olhar fundo – to look deeply

So in eu respiro fundo, fundo is functioning like an adverb: I breathe deeply.

You can say:

Eu respiro profundamente. – I breathe deeply / profoundly.

That’s grammatically correct, a bit more formal or neutral. However, respirar fundo is the most idiomatic, everyday way to say to take a deep breath in Portuguese (Portugal).

You normally wouldn’t combine them (✗ respiro fundo profundamente) because it sounds redundant and unnatural.

Can fundo go in a different place, like eu respiro três vezes fundo?

The natural order is:

Eu respiro fundo três vezes…

Placing fundo right after respiro is the standard pattern: verb + adverb.

Other options:

Eu respiro três vezes fundo… – possible, but sounds odd / marked.
Fundo, eu respiro três vezes… – unnatural.
Eu fundo respiro… – incorrect.

So for normal, natural Portuguese, keep:

[verb] + [fundo] + [how many times]
→ respiro fundo três vezes

Why is it três vezes and not something like as três vezes?

Três vezes literally means three times.

You only add the article (as três vezes) if you are talking about some specific, known set of three times:

Lembro‑me bem das três vezes que fomos a Lisboa.
I remember well the three times we went to Lisbon.

In your sentence, you’re just describing a general routine (not three particular, identified times), so you use três vezes without the article.

A small note on the word itself:

singular: a vez – time/occurrence
plural: as vezes – times/occurrences
with a number: duas vezes, três vezes, quatro vezes, etc.

Why do we use para in para relaxar and not por?

In this structure, para + infinitive expresses purpose (what the action is for):

respiro fundo três vezes para relaxar
→ I breathe deeply three times in order to relax.

In general:

para = for / in order to (purpose, intention)
por = because of / due to / by (cause, reason, means)

Compare:

Respiro fundo três vezes para relaxar.
I breathe deeply three times in order to relax. (my goal)
Estou nervoso por relaxar pouco.
I am nervous because I relax little. (cause, not goal)

So here para relaxar is the correct choice for expressing purpose.

Should it be para relaxar-me or para me relaxar in European Portuguese?

All of these are possible in Portugal:

…para relaxar. – very common, perfectly correct
…para relaxar-me. – standard written EP (enclisis after infinitive)
…para me relaxar. – very common in modern spoken EP

Notes:

Relaxar can be used without a reflexive pronoun with the meaning to relax (oneself), so para relaxar is fully natural.
Adding me (para relaxar‑me / para me relaxar) makes it explicitly reflexive (to relax myself), but the meaning in context is practically the same.

In careful written European Portuguese, many grammars still prefer option 2 (para relaxar‑me), but in everyday speech para relaxar and para me relaxar are both widespread and accepted.

Why don’t we use something like estou a respirar here? How would I say “I’m breathing deeply three times to relax (right now)”?

Your sentence describes a habit, so the simple present respiro is the natural choice.

If you want to describe an action happening right now, European Portuguese uses the progressive:

Estou a respirar fundo três vezes para relaxar.
I am breathing deeply three times to relax (right now).

Compare:

À noite, eu respiro fundo três vezes para relaxar.
At night I (usually) breathe deeply three times to relax. (habit)
Agora estou a respirar fundo três vezes para relaxar.
Now I’m breathing deeply three times to relax. (ongoing action)

So:

respiro → routine / general habit
estou a respirar → action in progress right now

Are there any pronunciation tips for this sentence in European Portuguese?

Yes, a few key points (European Portuguese):

À noite – /a ˈnoj.tɨ/
- noite has the diphthong oi like “oy” in English “boy”, but shorter and tenser.
- Final -e in noite is a reduced sound /ɨ/, not like English “ay”.
eu – /ew/
- Similar to English “eh-oo” quickly together, like “ehw”.
respiro – /ʁɨʃˈpi.ɾu/ (typical Lisbon/central accent)
- Initial r is a guttural sound (back of the throat), not like Spanish r.
- Final o is more like a closed “oo” than English “oh”.
fundo – /ˈfũ.du/
- un is nasal: air flows through the nose; don’t fully pronounce a clear n.
três – /tɾeʃ/
- The accent ê marks a closed “e”.
- Final -s is pronounced like sh /ʃ/ in most of Portugal.
vezes – /ˈve.zɨʃ/
- First z is like English z.
- Final -es becomes a reduced vowel /ɨ/ + sh /ʃ/ in many accents.
relaxar – /ʁɨ.laˈʃaɾ/
- x here sounds like sh.
- Again, guttural r at the start and end.

Saying the whole sentence slowly in rhythm can help:

À NOI‑te | eu RES‑PI‑ro | FUN‑do | TRÊS VE‑zes | pa‑ra re‑la‑XAR.