Cuando estoy ansioso, debería respirar profundo y hacer una pausa corta.

Both are grammatically correct, but they’re used in different situations.

• Cuando estoy ansioso (indicative) is used for:
  • General truths or habits:
    • Cuando estoy ansioso, debería respirar profundo… = Whenever I’m anxious, I should…
• Cuando esté ansioso (subjunctive) is used more for:

  • Future, not-yet-real situations, especially in instructions:

    • Cuando esté ansioso, respire profundo y haga una pausa corta. (doctor giving instructions)

    In your sentence, you’re talking about a general habit about yourself, so cuando estoy ansioso (present indicative) is the most natural choice.

Because estar describes a temporary state; ser describes an inherent characteristic.

• Estoy ansioso = I am anxious (right now / at this moment / in that situation).
• Soy ansioso = I am an anxious person (by nature, as a personality trait).

In the sentence, you’re talking about what you should do when you feel anxious, so a temporary state → estoy ansioso is correct.

Yes. Ansioso agrees with the subject in gender and number.

• Male speaker: estoy ansioso
• Female speaker: estoy ansiosa
• Group of men / mixed group: estamos ansiosos
• Group of women: estamos ansiosas

So a woman would say:
Cuando estoy ansiosa, debería respirar profundo y hacer una pausa corta.

In much of Latin America, ansioso often means eager, excited, looking forward to something, not only anxious/nervous in the emotional-disorder sense.

Examples:

• Estoy ansioso por verte. = I’m excited / eager to see you.
• Estoy ansioso por el examen. = I’m really worried / nervous about the exam.

For stronger, more clearly negative anxiety, people may say:

• Estoy muy nervioso.
• Tengo mucha ansiedad.

Context usually makes the meaning clear.

Spanish usually omits subject pronouns when the verb ending already shows the subject.

• Estoy ansioso already tells us the subject is yo.
• Cuando estoy ansioso… sounds natural and neutral.

You can say Cuando yo estoy ansioso…, but:

• It adds emphasis on I (as opposed to someone else).
• It can sound slightly heavier or more contrastive:
  • Cuando yo estoy ansioso, debería respirar profundo; cuando ellos están ansiosos, hacen otra cosa.

Both are possible, but they differ in strength:

• Debería (conditional) ≈ I should
  Softer advice, recommendation, something that would be good to do.
• Debo (present) ≈ I must / I have to
  Stronger obligation.

So your sentence:

• Cuando estoy ansioso, debería respirar profundo… = When I’m anxious, I should… (good idea, recommendation)
• Cuando estoy ansioso, debo respirar profundo… = When I’m anxious, I must… (strong rule or obligation)

After deber / debería, Spanish uses the infinitive, not a conjugated verb.

Pattern:

• debería + infinitive
  • Debería respirar = I should breathe
  • Debería hacer = I should do

If you said debería respiro, you’d be mixing two finite (conjugated) forms and it would be incorrect.

In your sentence:

• debería respirar profundo y hacer una pausa corta
  Both respirar and hacer are infinitives governed by debería.

Both are understood, but they differ slightly in style and frequency.

• Respirar profundo (literally “to breathe deep”):

  • Very common in everyday Latin American Spanish.
  • Profundo functions almost like an adverb here, even though it’s formally an adjective.
  • Sounds natural and conversational.

• Respirar profundamente:

  • Grammatically “cleaner” (true adverb form).
  • Sounds a bit more formal, like instructions, written language, or careful speech.

You will hear respirar profundo all the time in Latin America, especially in spoken language.

Yes. Respirar hondo is also very common and natural.

• Respirar profundo and respirar hondo both mean “to take a deep breath.”
• Slight nuance:
  • Hondo literally means “deep” in the sense of depth (like deep water).
  • Profundo is also “deep,” but often a bit more general/abstract.

In practice, they are near-synonyms here. You can use either:

• Cuando estoy ansioso, debería respirar hondo y hacer una pausa corta.

Both exist, but hacer una pausa is the more standard and widely accepted collocation in Spanish.

• Hacer una pausa = to take a pause / to pause
  • Very common in speech, writing, and formal contexts.
• Tomar una pausa:
  • Understood, and you will hear it, but it’s a bit more influenced by English take a break.
  • More common with descanso: tomar un descanso.

So, your sentence uses the most natural choice:

• …debería respirar profundo y hacer una pausa corta.

Three separate points:

1. Gender agreement

   • Pausa is feminine → la pausa / una pausa.
   • So it must be una pausa, not un pausa.

2. Adjective agreement

   • Corta must agree with pausa (feminine, singular) → pausa corta.

3. Adjective position (before or after)

   • Default in Spanish: adjective after the noun.
     • una pausa corta = a pause that is short (neutral description)
   • Una corta pausa is also possible but:
     • Sounds a bit more literary or stylistic.
     • Can slightly emphasize the shortness or make it sound more “elegant.”

For everyday speech, una pausa corta is the most natural.

Yes, it’s standard and recommended.

The structure is:

• Cuando estoy ansioso, (dependent clause)
• debería respirar profundo y hacer una pausa corta. (main clause)

In Spanish, when a subordinate clause (starting with cuando, si, etc.) comes before the main clause, we normally place a comma after it:

• Cuando estoy cansado, duermo.
• Si tengo tiempo, te llamo.

So:

• Cuando estoy ansioso, debería respirar profundo…
  The comma makes the sentence clearer and follows normal punctuation rules.

Yes, and it sounds very natural.

• Cuando estoy ansioso… = When I am anxious… (state)
• Cuando me siento ansioso… = When I feel anxious… (subjective feeling)

Nuance:

• Estoy ansioso: more “objective state.”
• Me siento ansioso: explicitly about how you feel.

Both are fine in this context. For many speakers, they’re almost interchangeable:

• Cuando me siento ansioso, debería respirar profundo y hacer una pausa corta.