Learn Hardcore Russian: Когда голова и спина устали, я делаю паузу и просто хожу по комнате. - When my head and back are tired, I take a break and just walk around the room.

In Russian, it’s very natural to use the past tense of устать (perfective: “to get tired / to have become tired”) in time clauses with когда to set up a condition:

Когда голова и спина устали, я делаю паузу…
Literally: When the head and back have (already) become tired, I take a break…

So Russian is focusing on the result of a completed process: at the moment when you decide to act, the “getting tired” has already happened. English usually uses the present state are tired, but Russian comfortably uses the past result устали here.

You could also say:

Когда голова и спина устают, я делаю паузу…

That sounds a bit more like a general habit without emphasizing completion; устали adds a slight feeling of “once they’ve gotten tired.” Both are acceptable, but устали is very common and natural.

Why is устали plural if голова and спина are each singular?

In Russian, when you have two or more singular nouns joined by и and used as the subject, the verb usually agrees in the plural:

голова и спина устали
the head and (the) back got tired → plural verb

This is similar to English: “my head and back are tired,” not “my head and back is tired.”

So:

голова устала (singular feminine)
спина устала (singular feminine)
голова и спина устали (plural, because there are two subjects)

Why don’t we say моя голова и моя спина устали to mean “my head and my back”?

Russian usually omits possessive pronouns (мой, моя, мои) with body parts when it’s obvious whose body we’re talking about. If the subject is я, it’s automatically understood that голова and спина are my head and back:

Когда голова и спина устали, я делаю паузу…
is naturally understood as
When my head and (my) back are tired, I take a break…

You use possessives mainly when you need contrast or emphasis:

У меня болит не моя голова, а твоя.
It’s not my head that hurts, but yours.

In normal, neutral sentences about your own body, leaving out моя sounds more natural.

Why is there a comma after устали: Когда голова и спина устали, я делаю паузу…?

The sentence has two parts:

A subordinate clause of time with когда:
Когда голова и спина устали
The main clause:
я делаю паузу и просто хожу по комнате.

In Russian, when a subordinate clause (starting with когда, если, потому что, etc.) comes before the main clause, you must separate them with a comma:

Когда… , я…
Если… , мы…
Потому что… , он… (although word order can change).

So the comma is required by standard punctuation rules.

Is there any difference between Когда голова и спина устали, я делаю паузу and Когда голова и спина устают, я делаю паузу?

Yes, there is a nuance:

устали (past, perfective устать)
Emphasizes that the process is completed: once they’ve gotten tired. It feels a bit more like a concrete event that has already happened at that moment.
устают (present, imperfective уставать)
Describes a general, repeated process: whenever they get tired / when they tend to get tired.

In practice, both can describe a habitual situation, and both are correct here. устали sounds like:
As soon as my head and back have become tired, I take a break.

устают sounds more like a neutral description of a usual pattern:
Whenever my head and back get tired, I take a break.

Why is it делаю паузу, not сделаю паузу?

Делать (imperfective) is used here to describe a repeated, habitual action:

я делаю паузу – I take (make) a break (whenever this situation occurs, as a habit).

Сделаю паузу (perfective, future) would mean “I will (at that particular time) take a break,” a one-time, concrete action:

Когда голова и спина устали, я сделаю паузу.
Sounds like a specific future plan: When my head and back get tired (on that occasion), I will take a break.

Because the sentence describes a general routine, the imperfective делаю is the natural choice.

Why is it хожу, not иду: …я делаю паузу и просто хожу по комнате?

Russian distinguishes between two main types of motion verbs:

идти – one-directional, movement toward a destination, typically a single trip.
ходить – multi-directional, repeated or back-and-forth movement, or a general ability/habit.

Хожу по комнате implies walking around the room, here and there, not toward a specific endpoint. It’s back-and-forth/aimless movement, which is exactly what you do during a break.

If you said иду по комнате, it would sound like a single purposeful progression through the room, which is less natural for “pacing / walking around.”

So:

я хожу по комнате – I walk around the room (pace, move here and there).
я иду по комнате – I’m going across the room (in one direction).

What does по комнате mean exactly, and why is комнате in that form?

По комнате literally means “around the room / around in the room.”

по
- dative case often expresses movement within an area, over a surface, or along some space.
комната (nominative) → комнате (dative singular).

So:

ходить по комнате – to walk around inside the room, in various directions.
Compare: ходить в комнате is possible but less idiomatic here; по комнате sounds much more natural for pacing around.

Other examples of по + dative with similar meaning:

гулять по парку – walk around the park
бегать по пляжу – run along the beach

Could we say гуляю по комнате instead of хожу по комнате?

You can say гуляю по комнате, and it would be understood, but there is a nuance:

гулять often suggests “taking a walk” in a more relaxed, sometimes outdoor or leisure context (park, street, nature).
ходить по комнате is the standard phrase for pacing around indoors, often when you’re thinking, resting your body, or just moving around.

So:

Я делаю паузу и просто хожу по комнате. – very natural.
Я делаю паузу и просто гуляю по комнате. – understandable, but slightly odd; it can sound like you’re “taking a walk” in your room, which is a bit playful or ironic.

What does просто add in я делаю паузу и просто хожу по комнате? Could we move it?

Просто here means “just / merely” and softens the second action. It suggests that the action is simple, nothing special:

я делаю паузу и просто хожу по комнате
→ I take a break and just walk around the room (I don’t do anything complicated, I only walk).

You can move просто a bit, but it usually stays near the verb or phrase it modifies:

я просто делаю паузу и хожу по комнате – I just take a break and walk around the room (the “just” applies more to the whole set of actions).
я делаю паузу и хожу просто по комнате – possible, but this word order is less neutral and can sound slightly unusual or emphatic.

The original …и просто хожу по комнате is the most natural and common placement.

Could we change the word order in Когда голова и спина устали to Когда устали голова и спина? Does it change the meaning?

Both are grammatically correct:

Когда голова и спина устали, я делаю паузу… – neutral, standard word order.
Когда устали голова и спина, я делаю паузу… – also correct, but with a slight emphasis on устали (the fact of becoming tired) and a slightly more “literary” or marked feel.

The meaning is essentially the same; the difference is stylistic and rhythmic rather than semantic. In everyday speech, the first version (голова и спина устали) is more typical.