I don't think the first clause should be negative in this sentence. It makes more sense to say: *Angekunywa maji, asingechoka." -- If she would drink water, she wouldn't get tired.
you have a point, as it is the reverse would be 'angekunywa maji angechoka' which doesn't make much sense. Unless of course we're talking stomach cramps because of drinking water then running?
You get super, super tired if you don't drink water. This sentence is not logical. They should change it.
Change it now please.
To what? Please be more descriptive when leaving suggestions
Also, why change it? Even if the statement doesn't make too much sense, it is grammatically correct. We're here to learn Swahili, not physiology or biology.