"They" instead of "he or she"

Question

Please advise how to change the following sentence so that it would refer to the 3rd person of unknown sex (as an additional constraint, we need to start the sentence with "The other person"):

I am active and I like to keep myself busy; I often feel bursting with energy

It's straightforward but a bit long using "he" or "she":

The other person is active and he or she likes to keep him- or herself busy; he or she often feels bursting with energy

What about using "they" as they sometimes do:

The other person is active and they like to keep themselves busy; they often feel bursting with energy

... or:

The other person is active and likes to keep themselves busy; they often feel bursting with energy

Does any of the sentences sound OK to a native speaker? Would you understand that the question refers to a single person, not a group of persons? Which version ("he or she" vs "they") is easier to read?

Answer 1

Singular they is well-attested, historical, and broadly understood. Your two sentences that use "they" will be understood by any native English speaker.

The only time to avoid singular they is when you specifically know your audience will have a problem with it --- political conservatives, religious traditionalists, and people who see themselves as cultural guardians. Among these people, singular they is a controversial sticking point. Among everyone else... most people accept it and barely notice it.

(Some style guides even specifically call for its use.)

Answer 2

I think the use of he or she is a bit awkward, however, your other sentences will do.

Answer 3

I would use the singular they as it sounds much less awkward than "he or she". I prefer the last sentence of the 4, since I think it flows better without the "they like" in sentence 3.

The second clause has a problem, though. "Bursting with energy" works like an adjective. It's not at thing you can feel, its a description of something. Instead, use something like "they are bursting with energy" or "they feel like they are bursting with energy."