Past Tense of “sweat”
The past tense of sweat is sweat; the past participle is sweat.
Why “sweat” behaves this way
"Sweat" comes from Old English "swætan," a weak verb closely related to the noun "swat" (sweat), itself tracing to a very ancient Proto-Indo-European root for perspiration shared across most Indo-European languages, including Latin "sudor" and the ultimate source of the English borrowing "sudorific." It was originally a fully regular verb in the older sense, and the modern zero-change past tense "sweat" (rather than "sweated") is actually a more recent development in American English rather than an ancient irregularity inherited from Old English.
British English strongly retains "sweated" as the standard past tense ("he sweated through the entire meeting"), while American English has increasingly adopted the zero-change "sweat" for the same slot, treating it like "cut" or "hit" — a genuine ongoing regional split similar to "sneaked"/"snuck," though somewhat less discussed in usage guides, likely because the alternation causes little actual confusion in practice. This kind of shift toward a zero-change pattern, rather than toward a fully regular "-ed" ending, is fairly unusual and suggests American English is drawing "sweat" toward the same small class as "cut" and "hit" by simple sound-shape analogy rather than pursuing regularization in the more typical direction. Canadian and Australian English tend to follow the British pattern more closely than the American one, another data point in the broader pattern of Commonwealth varieties generally preserving older or more traditional forms longer than American English does.
The common confusion
The main confusion is simply not realizing this is a live regional variation at all — many American writers assume "sweat" as a past tense must be some kind of error, since it looks identical to the present tense, when it's actually the standard, dictionary-recognized American form. British readers encountering "sweat" as a past tense in American writing sometimes read it as a typo for "sweated" rather than recognizing the dialectal difference. A separate confusion involves the noun "sweat" versus the plural clothing item "sweats," two nouns that share a root but describe entirely different things — bodily perspiration and a category of loose athletic clothing.
How it's actually used
"Sweat" extends figuratively to intense worry or effort — "don't sweat it," "sweat the details," "sweat equity" (labor invested in a project instead of money) — all of which keep whichever past-tense form, "sweat" or "sweated," matches the writer's regional dialect for the literal sense. It also functions as a transitive verb in the idiom "sweat someone" or "sweat information out of someone," meaning to interrogate or pressure them intensely, a distinctly informal, almost hard-boiled register borrowed from mid-century crime fiction.
Across the tense system
In the perfect tense, American English generally prefers "has sweat" ("he has sweat through three shirts today"), while British English uses "has sweated," the same regional split carried consistently through every tense; neither form is considered more "correct" in an absolute sense, only more standard for a given English-speaking audience. This verb rarely appears in the passive voice at all, since sweating is inherently something a body does rather than something done to it; the exception is figurative business writing, as in "the details were sweated over for weeks."
Common real mistakes
Neither "sweat" nor "sweated" is a grammatical error on its own — both are standard within their respective dialects — but plenty of writers undercut themselves by switching between the two mid-document rather than picking one and holding to it. A second, more specific error is applying the zero-change "sweat" to the noun form incorrectly, producing an ungrammatical "sweats" plural where the mass noun "sweat" (the perspiration itself) should remain uncountable. A third error is confusing the plural noun "sweats" (casual loose-fitting clothing, as in "wearing sweats") with the third-person verb form "sweats," two completely different grammatical categories that happen to share identical spelling. A fourth, more minor error is translating the idiom "sweat equity" too literally into other contexts, producing awkward phrases like "sweat investment" that aren't standard English collocations.
Examples
- He sweated through his shirt during the long meeting.
- She sweat through the entire workout without complaint.
- They had sweated over the budget for weeks before the presentation.
- Don't sweat the small stuff, her mother always said.
- He has sweat equity in this business that money can't replace.
- The runners sweated heavily in the midday heat.
Memory trick
Treat it like a dialect dial, not a right-or-wrong switch: British writing reaches for "sweated," American writing increasingly reaches for plain "sweat" — pick whichever matches your audience and stay consistent throughout a single piece of writing.