Po chorobie muszę bardziej dbać o zdrowie.

Because the preposition po in the sense of after requires the locative case.

• dictionary form: choroba = illness
• locative singular: chorobie

So:

• po chorobie = after the illness / after an illness

This is a very common pattern:

• po pracy = after work
• po obiedzie = after lunch
• po wakacjach = after the holidays

So here chorobie is simply the correct case form after po.

Muszę means I must or I have to.

It comes from the verb musieć = to have to / must.

A few present-tense forms are:

• muszę = I must
• musisz = you must
• musi = he/she/it must
• musimy = we must
• musicie = you all must
• muszą = they must

In this sentence, the subject ja = I is not stated, because in Polish the verb ending already shows who the subject is.

Polish often drops subject pronouns when they are clear from the verb form.

• muszę already means I must
• so ja is unnecessary unless you want emphasis

Compare:

• Muszę bardziej dbać o zdrowie. = I have to take better care of my health.
• Ja muszę bardziej dbać o zdrowie. = I have to take better care of my health.
  This sounds more emphatic.

This is normal in Polish and happens very often.

Bardziej means more.

It is used to make a comparative idea, similar to English more:

• bardziej dbać = to care more / to take better care

You can think of this sentence as meaning:

• I need to care more about health
• or more naturally in English: I need to take better care of my health

Other examples:

• bardziej się uczyć = study more
• bardziej uważać = be more careful
• bardziej odpoczywać = rest more

Dbać o is a verb expression meaning:

• to care for
• to take care of
• to look after
• in some contexts, to care about

In this sentence, dbać o zdrowie means to take care of one’s health.

Important: dbać normally goes with o + accusative.

Examples:

• dbać o zdrowie = care for health
• dbać o dzieci = take care of the children
• dbać o ogród = look after the garden

So it is useful to learn dbać together with o as a set: dbać o coś.

Because after dbać o, the noun goes in the accusative case.

• dictionary form: zdrowie = health
• accusative singular: zdrowie

For this noun, the nominative and accusative look the same, so nothing changes in form. But grammatically, it is still accusative.

So:

• dbać o zdrowie = to care for health

By contrast, o zdrowiu is a different case form, used in sentences like:

• Mówię o zdrowiu. = I’m talking about health.

That is because mówić o takes the locative, not the accusative.

It literally says health, but in this context it naturally means my health.

Polish often does not use possessives like my when the meaning is obvious.

So:

• dbać o zdrowie can mean to care about health in general
• in a personal sentence like this, it usually means to take care of my health

This is very natural Polish. English often prefers my health, but Polish does not need moje here.

Yes, it is singular because the sentence refers to an illness or the illness as one event/state.

• po chorobie = after an illness / after being ill

A plural version is possible in other contexts:

• po chorobach = after illnesses

But in this sentence, singular sounds natural because the speaker is talking about one period of sickness.

Also, Polish often uses a singular noun where English might say something broader, so po chorobie is a very normal phrase.

Yes. That would mean:

• Po tej chorobie muszę bardziej dbać o zdrowie.
• After this illness, I have to take better care of my health.

Adding tej makes it more specific. It suggests a particular illness already known from the context.

Compare:

• Po chorobie... = after an illness / after being ill
• Po tej chorobie... = after this illness
• Po mojej chorobie... = after my illness

All are possible, depending on what you want to emphasize.

Polish word order is flexible, but the given order is very natural.

• Po chorobie muszę bardziej dbać o zdrowie.

This sounds neutral and clear.

You can change the order for emphasis, for example:

• Po chorobie bardziej muszę dbać o zdrowie.
• Bardziej muszę dbać o zdrowie po chorobie.

These are grammatically possible, but they may sound more marked, less neutral, or focused on a particular element.

For learners, the original order is the best one to copy.

Dbać is the imperfective verb. It focuses on an ongoing habit or repeated action: taking care regularly.

That fits this sentence well:

• muszę bardziej dbać o zdrowie = I need to take better care of my health from now on

Zadbać is the perfective partner. It often suggests a more complete or one-time act of making sure something is taken care of.

Compare:

• Muszę bardziej dbać o zdrowie. = I need to take better care of my health.
• Muszę zadbać o zdrowie. = I need to take care of my health / I need to do something about my health.

Both are possible, but dbać stresses ongoing care, which is very natural here.

A rough guide:

• muszę ≈ MOO-shen
• dbać ≈ dbach

A few details:

• sz sounds like English sh
• ę at the end of muszę is often pronounced approximately like e or en in normal speech
• ć is a soft sound, a bit like a very soft ch in English cheek, but lighter
• db at the start of dbać may feel difficult for English speakers because both consonants are pronounced

You do not need perfect pronunciation right away, but it helps to notice that Polish often keeps consonant clusters that English speakers are not used to.

It is neutral and natural. It works in both everyday conversation and normal written Polish.

It is not especially formal, but it is also not slangy.

You could say it:

• in conversation with a friend
• to a doctor
• in a diary
• in a general statement about lifestyle

So it is a very useful, standard sentence pattern.