Eat before workout or not?

I always have the same problem. I prefer to eat after the morning workout. But, while swimming and doing all these harder sets for enduarnce / speed endurance I fear that I might faint. This stupid fear makes my workout less enjoyable. And it is like an obsession. Even when I do not feel weak at all my imagination works, because I am aware that muscles must be glycogen depleted, and then I have a feeling as if I were really getting week. This feeling gets so realistic! However, it must be only imagination because somehow I survive and nothing bad happens. Of course, I could eat some breakfast before, but I hate doing that so early. Besides, I read that if you eat nothing prior to exercise it helps you in burning fet and staying slim. Is it possible that you may faint or nearly faint out of exhaustion if you do not eat before workout in the morning? Or are your glycogen stores sufficient for 90 minutes of swimming at HR around 140-160 bpm?

I always have the same problem. I prefer to eat after the morning workout. But, while swimming and doing all these harder sets for enduarnce / speed endurance I fear that I might faint. This stupid fear makes my workout less enjoyable. And it is like an obsession. Even when I do not feel weak at all my imagination works, because I am aware that muscles must be glycogen depleted, and then I have a feeling as if I were really getting week. This feeling gets so realistic! However, it must be only imagination because somehow I survive and nothing bad happens. Of course, I could eat some breakfast before, but I hate doing that so early. Besides, I read that if you eat nothing prior to exercise it helps you in burning fet and staying slim. Is it possible that you may faint or nearly faint out of exhaustion if you do not eat before workout in the morning? Or are your glycogen stores sufficient for 90 minutes of swimming at HR around 140-160 bpm?