Prescyncope is when you feel as if you're about to pass out, but you don’t actually faint. It's sometimes referred to as near syncope. You may also feel lightheaded, sweaty, nauseous, warm, and weak, ...

When your brain doesn’t get enough oxygen, you may experience lightheadedness and weakness, as if you’re going to faint. If you don’t, that’s a presyncope. If you do faint, that’s called syncope.