Learn Hardcore Russian: Мне трудно контролировать стресс вечером. - It is hard for me to control stress in the evening.

Мне трудно контролировать стресс вечером.
- Мне – dative experiencer (“for me”).
- Трудно – impersonal predicative (“it is hard”).
- Контролировать стресс вечером – infinitive phrase explaining what is hard.

Russian often uses such impersonal structures with an infinitive:

Трудно жить одному. – It’s hard to live alone.
Невозможно всё запомнить. – It’s impossible to remember everything.

There is no “it” subject in Russian; English adds “it” just for grammar.

What case is мне, and why is it used here?

Мне is dative singular of я (“I”).

The dative is often used for the person experiencing a state:

Мне холодно. – I am cold.
Тебе грустно. – You feel sad.
Ему интересно. – He finds it interesting.

So Мне трудно контролировать стресс вечером literally means:
“To me it is hard to control stress in the evening.”

The dative answers “to whom / for whom is it hard?”

Why is стресс in this form and without a preposition?

Стресс here is the direct object of the verb контролировать.

Verb: контролировать – to control
Question it answers: что? (what?) → стресс

For inanimate masculine nouns, the accusative singular form is the same as the nominative:

Nominative: стресс
Accusative: стресс (same form)

So you see стресс with no preposition because контролировать is a normal transitive verb that takes a direct object in the accusative:

контролировать ситуацию – to control the situation
контролировать расходы – to control expenses

Could this be стрессом instead of стресс?

No, not with контролировать in this meaning.

Контролировать normally takes accusative (direct object):
- контролировать стресс – to control stress

Стрессом is instrumental case. That would suggest something like “to control with stress”, which doesn’t fit the intended meaning. So:

✅ контролировать стресс – correct
❌ контролировать стрессом – wrong / would sound like you use stress as a tool to control something else

Why is it вечером and not в вечер?

With parts of the day, Russian usually uses a special adverbial form (historically instrumental case) instead of в + accusative:

утром – in the morning (not в утро in normal speech)
днём – in/at daytime (not в день here)
вечером – in the evening (not в вечер)
ночью – at night (not в ночь in this sense)

So вечером means “in the evening / at nightfall time” in a general, time-of-day sense.

В вечер is either wrong or extremely unusual in modern, neutral Russian.

Can I move the words around, for example Вечером мне трудно контролировать стресс?

Yes. Russian word order is flexible, and several variants are natural:

Мне трудно контролировать стресс вечером.
– Neutral: mild focus on what is hard (controlling stress in the evening).
Вечером мне трудно контролировать стресс.
– Brings “in the evening” to the front, emphasizing the time:
“In the evening, it’s hard for me to control stress.”
Мне вечером трудно контролировать стресс.
– Emphasizes that specifically in the evening it is hard for me.

All three are acceptable and mean essentially the same, with slightly different emphasis. What you can’t do is split phrases in a strange way, like:

❌ Трудно мне вечером контролировать стресс – not wrong grammatically, but marked; sounds more emotional or poetic.

Could I say Мне сложно контролировать стресс вечером instead of Мне трудно…? Is there a difference?

Yes, you can. Трудно and сложно are very close in meaning here.

трудно – hard, difficult (often also physically / emotionally hard)
сложно – complicated, hard (focus slightly more on complexity)

In everyday speech, in this type of sentence:

Мне трудно контролировать стресс вечером.
Мне сложно контролировать стресс вечером.

both are fine and will usually be understood as the same thing. Use whichever sounds nicer to you; трудно is maybe a bit more neutral and more common in basic patterns.

Why is контролировать in the infinitive? Can I conjugate it instead?

After impersonal predicates like трудно, легко, нужно, можно, Russian normally uses the infinitive:

Трудно понять. – It’s hard to understand.
Легко сказать. – It’s easy to say.
Мне нужно работать. – I need to work.

So:

Мне трудно контролировать стресс вечером.
– It’s hard for me to control stress in the evening.

You cannot say:

❌ Мне трудно контролирую стресс вечером.

because controlling here is part of the thing that is hard; in Russian this is expressed by infinitive after трудно.

If you want a normal finite verb, you change the structure:

Я с трудом контролирую стресс вечером. – I barely / with difficulty control stress in the evening.

Is there a Russian verb like English “to stress”? Why not Мне трудно стрессовать вечером?

There is a colloquial verb стрессовать (“to stress, to be stressed”), but:

Мне трудно стрессовать вечером would mean something like
“It’s hard for me to be stressed in the evening” – which is not what you want.

In the original sentence, стресс is used as a noun, and you are controlling it:

контролировать стресс – to control stress
(or: справляться со стрессом – to cope with stress)

Natural alternatives keeping the same idea:

Мне трудно справляться со стрессом вечером.
Мне сложно управлять стрессом вечером.

How would I say this without the impersonal Мне трудно, using a normal “I + verb” structure?

A common alternative is:

Я с трудом контролирую стресс вечером.

Literally: “I control stress in the evening with difficulty.”

Nuance:

Мне трудно контролировать стресс вечером.
– Emphasizes your feeling of difficulty; more about your state.
Я с трудом контролирую стресс вечером.
– Emphasizes the action: you do control it, but it’s hard / barely.

Both are correct; your original sentence is very natural and common.

Where are the word stresses (accents) in this sentence?

Here is the sentence with stressed syllables marked:

Мне тру́дно контролирова́ть стресс ве́чером.

Syllable breakdown:

Мне – mne (one syllable, no alternative stress)
тру́дно – TRU-dno
контролирова́ть – kon-tro-LI-ro-vatʹ (stress on -ли-)
стресс – one syllable (no alternative stress)
ве́чером – VE-che-rom

Approximate pronunciation (Latin letters):
Mne TRU-dna kan-tra-LI-ra-vat’ stres VE-che-ram.

Why is there no form of “to be” like есть in this sentence?

In Russian, in the present tense, the verb быть (“to be”) is usually omitted:

Он врач. – He is a doctor. (literally: He doctor.)
Мне холодно. – I am cold. (literally: To me cold.)

So:

Мне трудно контролировать стресс вечером.
– literally: To me hard control stress in-the-evening.

You do not say:

❌ Мне есть трудно контролировать стресс вечером.

Using есть like that is wrong in modern standard Russian. The “is” is just understood from the structure.

Is there any difference between вечером and по вечерам here?

Yes, there is a small nuance:

вечером – this/that evening or in the evening in general (often understood as “in the evening” as a time-of-day frame, maybe on a particular day or generally, depending on context).
по вечерам – in the evenings / on evenings (habitually, regularly).

So:

Мне трудно контролировать стресс вечером.
– It’s hard for me to control stress in the evening (could be general, or about a particular / typical evening).
Мне трудно контролировать стресс по вечерам.
– It’s hard for me to control stress in the evenings (as a regular pattern).

Both are correct; по вечерам makes the habitual, repeated meaning explicit.