O suor diminui durante o descanso.

Portuguese uses definite articles much more often than English.

In a general statement like this, o suor means sweat in a general sense, and o descanso means rest in a general sense. In English, we often leave the article out, but in Portuguese, using o/a/os/as is very common and natural.

So:

• O suor diminui durante o descanso. = a normal, natural sentence
• Suor diminui durante descanso. = sounds incomplete or like a headline/style shortcut

Diminui is the 3rd person singular present tense of diminuir.

That means it matches subjects like:

• ele diminui
• ela diminui
• você diminui
• o suor diminui

So in this sentence, o suor is the subject, and diminui means decreases or goes down.

Because the subject is singular: o suor.

• o suor diminui = sweat decreases
• os níveis diminuem = the levels decrease

The verb has to agree with the subject. Since suor is singular, the verb is singular too.

A helpful approximation in Brazilian Portuguese is:

jee-mee-NOO-ee

A few notes:

• In many Brazilian accents, di before i sounds a bit like jee
• The ending -ui is pronounced clearly, not like English wee
• Try to keep all the vowels audible: di-mi-nu-i

So it is not a one-syllable English-style ending. It is more like di-mi-nu-i.

A rough pronunciation is:

soo-OR

The stress is on the last part. In careful speech, many speakers pronounce both vowels clearly, something like su-or.

Do not pronounce it like English sore. Keep it more clearly separated into vowel sounds.

Durante means during and is used before a noun or noun phrase.

Here:

• durante o descanso = during rest

It is useful when you want to talk about something happening within a period of time.

Compare:

• durante o descanso = during the rest
• enquanto descansa = while he/she/you rest(s)

So durante is followed by a noun, while enquanto is followed by a clause.

Because in normal Portuguese, descanso usually needs the article here.

So durante o descanso sounds natural and complete.

Without the article, durante descanso, it sounds unnatural in standard everyday Portuguese. Portuguese generally prefers the article in this kind of structure.

Good question. Some Portuguese prepositions contract with articles, but durante normally does not.

For example:

• de + o = do
• em + o = no
• a + o = ao

But:

• durante + o = durante o
  not a contraction

So durante o descanso is exactly what you should expect.

Not necessarily. Descanso means rest, a break, or a period of recovery.

It can include sleep in some contexts, but by itself it is broader than sono or dormir.

So this sentence is about a resting period in general, not specifically sleeping.

They are related, but not always identical.

• suor = sweat, the liquid itself
• transpiração = perspiration/sweating, often the process

In many contexts, they overlap, and native speakers may use both naturally. But in this sentence, o suor diminui focuses more directly on the sweat itself or the amount of it.

Yes, absolutely. That is very natural.

Both are correct:

• O suor diminui durante o descanso.
• Durante o descanso, o suor diminui.

The second version puts more focus on the time expression during rest. The first version is the more neutral subject-verb-complement order.

Only if the subject is already understood from context.

By itself, Diminui durante o descanso sounds incomplete, because the listener will usually ask: What decreases?

Portuguese can omit subjects in some cases, but here the omitted subject would not be clear enough unless the context already made it obvious.

Yes. It sounds natural, especially in health, exercise, biology, or medical contexts.

It has a slightly informative or explanatory tone, like something you might hear in:

• a lesson
• a fitness explanation
• a health article
• a scientific description

In very casual speech, someone might say the same idea in other ways, but this sentence is perfectly normal and correct.