Are There Problems With Running On An Empty Stomach?

There are many reasons to run with no food in your stomach. You escape the digestive issues often triggered by running after eating certain foods. Some people swear running on empty can even boost your endurance and speed up fat loss. But are there problems with running on an empty stomach?

Running on an empty stomach is problematic because it can negatively affect running performance, hinder weight loss, diminish muscle mass, increase injury risk, and potentially cause dangerously low blood sugar levels in people with diabetes or Addison’s disease.

Eight or so hours after eating (for example, after a night’s rest), your body’s used up all its readily available energy (glycogen). At this point, you've got what's called an empty stomach. Running on empty, or fasted running, can be risky. Let’s unpack the problems with fasted running and ways to make it safer.

Problems With Running On An Empty Stomach

Fasted running can negatively affect your running performance, body composition, health, and safety.

Before you lace up your running shoes several hours after you’ve eaten anything, get clued up on five problems with running on an empty stomach.

#1: Running On An Empty Stomach Can Drop Your Performance

You need to challenge your body to get fitter, faster, and stronger. But when you’re running on empty, you might not have the energy to push yourself fast or long enough to improve your exercise performance.

If you don’t have enough readily available energy to fuel a speedy or long run, hunger or fatigue can strike before you’ve made progress with your fitness goals.

What’s more, running on an empty stomach can slow down your post-exercise recovery, putting the brakes on your future performance.

# 2: Running On An Empty Stomach Can Slow Down Weight Loss

So, you’ve heard that running on an empty stomach will turn you into a fat-burning machine and speed up weight loss? It’s not that simple. Fasted running can make your body tap into its fat reserves for energy once it’s burned through your muscles’ sugar supply, but this isn’t a failsafe way to lose weight.

High-intensity exercise is the real calorie-scorcher but, with an empty stomach, you could feel pooped a few minutes into a moderate- or even low-intensity workout.

So, although you could eventually get your energy from fat instead of sugar, you might not have the oomph to exert yourself enough to burn all that many calories. Plus, some research has found that when you burn fat during a fasted run, your body has less fat-burning power later in the day.

Studies have also uncovered that your cravings might go into overdrive after a fasted run as your body tries to top up your energy stores. You'll likely take in extra calories if you go into an eating frenzy, upping the chance that you’ll put on pounds instead of losing them.

# 3: Running On An Empty Stomach Can Raise Your Injury Risk

When you run on empty, you can exhaust both your body and mind. Suppose you push your energy-drained body to keep running even though every stride takes effort. In this case, you’ll increase your injury risk.

Maintaining good running form when you’re tired is challenging; you’re more likely to slump, relax your core muscles, and lose control over your foot strike. All these factors up the chances that you’ll injure yourself.

Your brain might also get tired, fuzzy, and less aware of your surroundings. As a result, you could be more vulnerable to potential threats in your environment, like oncoming cars and menacing strangers.

# 4: Running On An Empty Stomach Can Trigger Muscle Loss

You know how you get when you’re hangry? How you gobble up whatever gives you the quickest energy boost?

_{Garfield eating lasagna for quick energy boost; via GIPHY}

Well, your body is the same.

Your body can get faster energy from your muscles than from your fat, so when you’re running in a fasted state, you’ll break down your muscles’ sugar stash before you raid your fat stores. Take a strenuous fasted run, and you risk losing muscle mass, which will drop your metabolism. Double trouble.

Another way fasted running can cause muscle loss is by triggering your body’s stress response. When you run on empty, your body might feel threatened and release cortisol, the stress hormone. High cortisol levels can then cause your muscle mass to break down.

This effect is worst if you run first thing in the morning after fasting overnight. Your cortisol levels peak early in the morning. Add a tough fasted run to the mix, and your cortisol levels could soar, potentially resulting in shrinking muscles.

# 5: Running On An Empty Stomach Is Unsafe For Some People

Fasted running is an especially big problem for people who struggle to control their blood sugar levels.

If you have diabetes or Addison’s disease, fasted running could drop your blood sugar, potentially resulting in dangerously low levels. So, avoid running on an empty stomach if you have one of these conditions.

Tips For Running On An Empty Stomach

There are ways to make running on an empty stomach safer. If you have your mind set on fasted running, follow these guidelines to cut down your risk of problems:

• Keep your run to an hour or shorter. Run for 40 to 60 minutes max.
• Stick to low-intensity running. Run at a pace that lets you have a conversation.
• Hydrate. Drink a glass of water before your run.
• Fuel up after your run. Eat a meal within 30 minutes after your run to efficiently replenish your energy stores.
• Listen to your body. End your run early if you start feeling dizzy or like you’re about to pass out.
• Bring carbohydrate gels or energy chews with you to add quick energy when you need it

_{One of my favorite energy chews to take on a run; Image courtesy of Amazon.com}

Conclusion

The downsides of running on empty include poorer performance, sabotaged weight loss attempts, shrinking muscle mass, higher injury risk, and possible dangerously low blood sugar if you've got diabetes or Addison's disease.

Minimize your chances of problems by keeping your fasted runs short and easy, hydrating before and after your runs, refueling within half an hour of finishing running, and taking a breather if your body tells you it's not coping.