Learn Hardcore Finnish: Minusta terveys paranee, kun nukun hyvin. - I think my health improves when I sleep well.

Minusta is the elative case (-sta) of minä (I). Literally it means from me, but in this kind of sentence it means in my opinion / I think that.

So:

Minä = I
minusta = from me → in my opinion

It’s not the subject of the verb; it’s an “opinion adverbial” attached to the whole clause terveys paranee.

Is Minusta the same as saying I think in English?

Functionally, yes.

Minusta terveys paranee ≈ I think (that) health improves.

But grammatically it’s different: Finnish doesn’t add a whole extra verb like think; instead it uses this elative form (minusta, sinusta, hänestä, meistä, teistä, heistä) to show whose opinion it is.

What is the difference between Minusta and Minun mielestäni?

Both mean in my opinion, but:

Minusta is shorter and very common in speech and informal writing.
Minun mielestäni is a bit more explicit and often feels slightly more formal or careful.

Examples (same meaning):

Minusta terveys paranee, kun nukun hyvin.
Minun mielestäni terveys paranee, kun nukun hyvin.

You can use either; minusta is perfectly natural.

Is Minusta the subject of paranee?

No. The subject is terveys (health).

Terveys (health) = subject
paranee (improves) = verb
Minusta (in my opinion) = adverbial expressing whose opinion it is

So structurally: “In my opinion, health improves …”

Why is terveys in the basic (nominative) form and not something like terveyttä?

Because terveys is the grammatical subject of the verb paranee. Subjects are normally in the nominative case.

Terveys paranee. = Health improves. (subject in nominative)

The partitive terveyttä would be used in different structures (e.g. with some verbs or when talking about partial amounts), but not as the straightforward subject here.

How would I say “my health improves” more literally?

You would usually use the possessive suffix -ni:

Terveyteni paranee, kun nukun hyvin.
= My health improves when I sleep well.

You can also add the pronoun:

Minun terveyteni paranee, kun nukun hyvin.

Minun terveys paranee (without the suffix -ni) is grammatically wrong. You need the possessive suffix if you want to mark possession directly on terveys.

What exactly does paranee mean, and how is it different from parantaa or parantuu?

All are related to getting better / improving, but:

parantua = to get better, to recover (intransitive: something improves by itself)
- terveys paranee / terveys parantuu = health improves / gets better
parantaa = to cure, to improve something (transitive: someone improves something)
- Uni parantaa terveyttä. = Sleep improves health.

Paranee is the 3rd person singular present tense of parantua (here used in the sense improves / gets better).

What does kun mean here, and could it also mean because?

In this sentence kun means when:

… kun nukun hyvin. = … when I sleep well.

Kun can sometimes mean because, but that depends on context and intonation. Here, the most natural reading is temporal: health improves when good sleep happens, not explicitly because of it (even if that’s logically implied).

Why is there a comma before kun?

In Finnish, a subordinate clause introduced by words like kun, että, jos, etc. is normally separated by a comma.

So you get:

Minusta terveys paranee, kun nukun hyvin.
- Main clause: Minusta terveys paranee
- Subordinate clause: kun nukun hyvin

Even if the kun-clause comes first, you still use a comma:

Kun nukun hyvin, minusta terveys paranee.

Why is it nukun and not something like nuku or nukon?

The verb is nukkua (to sleep). Its present tense forms are:

minä nukun
sinä nukut
hän nukkuu
me nukumme
te nukutte
he nukkuvat

So nukun is the correct 1st person singular form: I sleep.

Nuku is the imperative form (sleep!), and nukon doesn’t exist.

Why is there no minä before nukun?

Finnish usually drops subject pronouns, because the verb ending already shows the person.

Nukun hyvin. = I sleep well. (perfectly normal without minä)
Minä nukun hyvin. = also correct, but minä is only used for emphasis or clarity.

In your sentence, nukun clearly refers to I, so minä is not needed.

Are Minusta and nukun referring to the same person?

Yes.

Minusta = in my opinion (from me)
nukun = I sleep

They both refer to the speaker. Grammatically, Minusta is an adverbial of opinion, and nukun has an implied subject I (shown by the verb ending).

Can I make it more general, like “Health improves when you sleep well”?

Yes. The most natural generic Finnish is to use kun nukkuu (3rd person singular with no subject):

Minusta terveys paranee, kun nukkuu hyvin.
= I think health improves when one/you sleep(s) well.

Here nukkuu is impersonal/generic, not specifically I. The sentence becomes a general statement about people.

Can I change the word order, for example put kun first?

Yes, Finnish allows flexible word order, with changes in emphasis:

Minusta terveys paranee, kun nukun hyvin.
(Neutral: “In my opinion, health improves when I sleep well.”)
Kun nukun hyvin, minusta terveys paranee.
(Emphasises the condition “when I sleep well”.)
Terveys paranee minusta, kun nukun hyvin.
(Focuses on terveys paranee; minusta feels a bit more like an afterthought.)

All are grammatically correct, but the first is the most straightforward.

Why is it hyvin and not hyvästi or hyvää?

Hyvin is the normal adverb form of hyvä (good) and means well:

nukun hyvin = I sleep well

Hyvästi is rare in modern standard Finnish and mostly seen in fixed expressions (e.g. hyvästi! = farewell!).

Hyvää is the partitive of hyvä, used e.g. in:

Hyvää yötä! = Good night!

So for sleep well, the correct and natural choice is nuku hyvin (imperative) / nukun hyvin (statement).