Can You Exercise While Fasting?

Fasting has become an increasingly popular way to lose weight and improve health. However, many people wonder if they can continue their normal exercise routine while fasting. This article will explore the science behind exercising while fasting and provide tips on how to make it work.

Your Body Has Energy Stores to Use While Fasting

When you eat food, it provides calories which are units of energy. If you don’t use all of the energy from the food right away, your body stores some of it for later use. This stored energy is body fat.

During a fast, when you stop eating for an extended period, your body switches from burning energy from food to burning energy from stored body fat. This is because your body was designed to be able to function without constant food intake.

100,000 To 200,000 Calories of Energy Stored As Body Fat

Your body has the ability to store calories which is just food energy so when you store it you also have the ability to take it back out of storage and that’s what happens when you’re fasting your body is essentially like a hybrid car which sometimes can use gas and sometimes can use electricity and it can switch between the two.

So even though you have stopped eating, you still have plenty of energy available in the form of body fat. An average sized person likely has somewhere between 100,000 to 200,000 calories of energy stored as body fat. That’s plenty of energy to power you through exercise session while fasting.

Exercise Normally While Fasting

The takeaway is that you should be able to continue exercising normally during a fast. The only difference is that your body will pull energy from your fat stores rather than from food.

The simple thing to think about when you’re fasting is really that you should be doing everything that you normally do when you’re not fasting the only difference is that you’re allowing your body to use the energy that’s been stored away.

There’s no need to decrease your exercise intensity or duration just because you are fasting. Listen to your body, but in general you can continue with your normal workout schedule.

Some high intensity workouts may need to be adjusted, so pay attention to how you feel. But regular cardio and strength training should be completely fine.

Optimal Time to Exercise While Fasting

You can exercise at any time during your fast. However, there are advantages to exercising towards the end of your fasting period, right before you break the fast. This is known as training in a fasted state.

For example, if you are doing a 16 hour fast, you would wait until hour 14 or 15 to do your workout, and then eat your first meal right after. Or if doing a 24 hour fast, you’d exercise around hour 22 and then eat.

There are two big benefits to training in the fasted state:

1. Increased Fat Burning

When you are several hours into a fast, your body has lowered insulin levels and switched to burning fat for fuel. Exercising in this fat burning state will tap into your body fat stores even more.

The increased norepinephrine and activation of the sympathetic nervous system during fasting signals your body to push out stored energy. This makes it easier for you to access fat during exercise.

2. Improved Recovery

Growth hormone levels increase during fasting. This helps prime your body for growth and recovery after exercise that causes minor muscle damage.

Having this training in the fasted state is beneficial from two hormonal standpoints one is that you’re activating the system so you’re going to be able to train harder and second is that your growth hormone is going to go up so that you’re going to recover faster.

After your fasted workout, eating protein and nutrients will allow your body to fully repair and build muscle.

Not Only Can You Exercise While Fasting But…

In summary, not only can you exercise while fasting, but doing fasted workouts can actually improve your results. During a fast your body is already in fat burning mode, so exercising in this state will tap into fat stores even more.

Placing your workouts towards the end of your fasting period can also optimize hormone levels for both better performance during the workout, and improved recovery afterwards.

If you pair fasting workouts with proper nutrient intake in your eating window, you can build muscle and improve body composition. Just listen to your body and adjust exercise intensity if needed. But there’s no need to be afraid of continuing your normal training schedule while implementing intermittent fasting.