When to Do Cardio

When To Do Cardio

If you’re going to do cardio, you certainly want to optimize the results for your time and effort, right? So when to do cardio is an important question!

You want to make sure you are burning maximum fat and optimizing your workout time. Cardio is one of the healthiest things you can do for your body, but there are optimum times to do it.

Really, any time you do cardio your fitness and health will benefit. And there will oftentimes not be a perfect time to do a cardio workout given a busy schedule. But it’s still a good idea to know when the best time is to do your workouts.

And there are a number of factors to consider in deciding the best time: the time of day, before or after meals, before or after weights, and more. A number of these factors will be determined by each person’s goals. But it’s safe to say that most people spend time in the gym to burn fat, and increase muscle. So for this goal, we have the answer!

Cardio on an Empty Stomach

When Should I Do CardioFirst, to understand the optimum exercise schedule requires understanding a little physiology. If you eat or drink prior to your cardio workout, this will increase your blood sugar levels, and as a result your glucose levels as well.

If your body has higher glucose levels, then this glucose will be used as fuel during your workout. This means the glucose will be burned for fuel, and not fat. And glucose makes an excellent fuel source to power your workouts, so if your body is replete with glucose, your body will gladly focus here for the fuel source.

However, if you do your workouts on an empty stomach, you will have minimal glucose in your system to burn as fuel. As a result, the energy your body will utilize to fuel your workout will be fat. So it is always best to perform workouts on an empty stomach to maximize the fat you burn.

Cardio in the Morning or Evening

So it is always best to do your cardio workout on an empty stomach, which for most people means first thing in the morning. This will result in your body burning fat as the energy source, and not glucose. (1)

Doing cardio workouts first thing in the morning, before you eat, ensures that your body burns fat as the primary fuel source during your workout. 

If you do cardio after eating, you have offered your body food as the primary fuel source, and fat becomes secondary.

Cardio in the Morning

If you workout or do cardio after eating, your body is going to use that stored food as the fuel source. But first thing in the morning on an empty stomach, your body has no choice but to burn fat as the primary fuel source.

This will maximize the fat burning aspect of your workout, which is a priority for most people. There are still many other great reasons for cardio workouts, but fat burning is generally high on the list.

If you hit the gym first thing in the morning when you wake up, you can be rest assured that your body will be in maximum fat-burning condition. This is added motivation by itself, as you know one of your primary fitness goals is front and center.

And then within your workout, another important question is when to do cardio? Should you do cardio before or after weight training? You can find the important answer to that question here.

Learn more about other cardio workouts.

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David Williams

A diet and fitness enthusiast, David is an ex-Army Airborne Ranger and Infantry soldier with decades of fitness and wellness experience. A West Point graduate with a degree in engineering, he focuses on technical research related to fitness, nutrition, and wellness. He loves the beach and working out, and spending time with his wife and daughters.

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  1. Times, T. A. (2014, June 24). Shocking benefits of exercising on an empty stomach. HuffPost.

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