With regards to a 24 hour fast, I know from experience, you can still exercise while fasting, in a safe and effective manner. There are just a few tweaks I make to my fitness routine while fasting. When I exercise after a number of hours have passed since I’ve last eaten, I don’t lift the heaviest weights I can, I take it a little easier on myself. As always, I pay close attention to my energy levels when starting a workout and I always listen to my body. If something doesn’t feel right one day, I don’t push it. If you’re new to exercising, or to fasting, please speak with your doctor before starting either activity.
How Does Exercising While Fasting Work?
When you exercise on a day that you’ve eaten breakfast, lunch and dinner, your glucose levels remain elevated in your body throughout the whole day. This probably causes you to burn exclusively glucose for fuel during your workout. When you exercise towards the end of a 24 hour fast, your body has burned most, if not all of it’s glucose reserves. There’s not much energy left in the form of glucose, to burn. But fear not, most of us still have lots of energy on our bodies to burn, in the form of fat. Fat reserves can keep many of us moving for quite some time in the gym!
For the first couple of months, I did exercise while fasting, but my energy was a little lower, so I kept things less intense. You may experience a decrease in your energy levels while working out at first, until your body becomes more efficient at burning fat. At the start of fasting, I often did yoga and isometric hold work during the fasting period. However, after four months of fasting, I was able to get a lot more aggressive with my workouts. In fact, my intensity during a fast isn’t much different now; I’m able to maintain my energy levels.
Let’s Clear up a Couple of Exercising while Fasting Questions
- Won’t fasting burn away at my muscles, especially if I exercise while fasting?
Many of us have heard that if we exercise on an empty stomach, our body will burn away at our muscles for fuel during and after a workout. Science shows that we burn body fat before muscle. Only when our body fat is really low (less than 4%, which is lower than most professional athletes), will our body use muscle for energy. So if we don’t have energy to burn, in the form of glucose (from eating all day), our body kicks into burning fat for fuel. This is great news – we burn more fat while exercising during a fast! More good news – our Growth Hormone, which is responsible for helping build muscle and bone, increases during fasting. This helps us recover quicker after a workout and build more muscle overall. - Should I feel dizziness or headaches during a fast, especially while working out? Although dizziness and headaches can result during and after exercising while fasting, these symptoms should not be accepted. I’ve found that the number one thing that kicks a fasting headache for me, is to drink a lot of water. My water intake increases by 25% on fasting day. If you want almost instant results, add a sprinkle of sea salt into your water. I do remember feeling dizzy during my first couple of fasts. I immediately stopped my workout and laid down and the feeling went away within minutes. Dizziness should definitely be something you share with your doctor.
To Sum it up…Exercising while fasting
It’s been my experience, that you can still exercise safely and effectively, throughout a 24 hour fast. Even though we’re not eating food for fuel, most of us still have lots of energy on our bodies to burn, in the form of fat. These fat reserves can keep many of us moving for quite some time in the gym. So if we don’t have energy to burn, in the form of glucose (from eating all day), our body kicks into burning fat for fuel. We’re able to burn more fat while exercising during a fast!
Despite my positive, personal experiences with exercising while fasting, I recommend that you check-in with your doctor before trying both fasting itself, and exercising while fasting.