I’ve been doing IF for a month. I did it previously for a few months a couple years ago as well. I’ve done one 36 hour fast before. Yesterday I tried a 40 hour. I had coffee in the morning and some herbal teas through the day.
It went well, but starting about 25 hours in I felt like everything was harder. A little bit of a heart racing feeling. Nothing crazy, but I pay close attention to my resting heart rate for fitness reasons. It was a couple beat higher than usual (normally 54, where I was at 58/59 after hours 25 of the fast), but it felt like I was working way harder and my heart rate would spike and I would feel like my heart was pounding much more frequently than usual. Nothing dramatic, just up to 100/105 bpm when I would expected to be 90-95 (standing up to walk across the room, for example).
About 3 hours after I ate it faded away. I wasn’t ever concerned. It basically felt like the a day where I worked out a little too hard in the morning. Chalked it up to electrolytes and cortisol.
I think I drank too much water and maybe flushed out my electrolytes too early on?
Definitely got ketosis cotton mouth about 20 hours into it. By hour 36 I had a slight acetone smell to my urine.
Thoughts? Is this just my body working harder and adjusting to no carbs and is this a kind of keto flu?
You definitely need to take potassium magnesium and sodium OP. Everyone is different but I know when my potassium is low and I have seen this on lab work not extended fasting but working out a lot & IF/ low carb. If you are ever feeling really weird you should break your fast and get some salty broth and food right away. I start taking electrolytes day one. People will say that it isn’t necessary but they don’t know my body. Good luck moving forward and great work especially being self aware.
when you’re fasting your body is in a stress mode. Usually my blood pressure rises in the first few days and so does my pulse… I wouldn’t worry about it. After all in nature this would make you more alert to get food.