Someone from Oakville, Ontario, CA posted a whisper, which reads "CAUTION: Pokemon Go may cause significant blood flow, perspiration and weight loss. Don't panic you won't die it's just called exercise "
Technically true, though are many ways around this. Other priority moves, sand or hail being up to finish the job or just switching in something to tank the quick attack. Also, if that rattata eats a stealth rock or any variety of spikes, you're toast.