Let’s talk exercise!
We all know that exercise is good for you, but what about when fasting? How does that change things?
We’re going to break it down into two categories: the athlete, and the average person (non-athlete).
Exercise for Athletes during an Extended Fast
As an athlete, you’re already used to strenuous physical activity.
But athletic performance while doing an Extended Fast could be a whole new ballgame (pun intended).
Impact on aerobic activities
If you’re into running or swimming or other sports that get your heart rate up, the main concern is going to be energy.
When you were not fasting, your body ran on glucose mostly, but now you’re going to switch over to burning fat for fuel.
Fat is a much more efficient source of fuel than glucose.
As a result, many athletes report increased energy and peak performance during a fast.
But if you’re new to fasting and were not doing Keto or Carnivore before, that switch over to fat burning can be tough. It can take up to a month to get fully Keto-adapted.
So be prepared for an initial drop in performance. But it will come back and most likely even improve after your keto adaptation.
Impact on Anaerobic Exercise
Bodybuilders love fasting to get their body fat whittled down before a performance.
But often they are concerned about muscle loss, for obvious reasons.
You’ll be glad to know that there’s not much to worry about. As long as you do have some fat to burn, your body is not going to burn muscle.
“But wait,” you say. “I had a DEXA scan and it said I lost muscle!” No, you didn’t lose muscle (unless you had no body fat to burn). What you lost was the glucose stored in muscle!
Another benefit of Extended Fasting is that HGH (Human Growth Hormone) actually increases pretty drastically during a fast.
So you are way more likely to gain muscle than you are to lose it.
A Word of Caution!
If you are an athlete, you’re more than likely already in great physical shape.
You might not have enough body fat to sustain an Extended Fast.
You should not fast if you currently have a low BMI, defined as less than 18.5, per Dr. Fung. Be safe, not stupid.
Tips to Maintain Athletic Performance
No matter what type of athlete you are, the following tips can help you maintain performance during an Extended Fast and keep you safe:
Stay hydrated and take your electrolytes!
Proper hydration and electrolytes are serious business during an Extended Fast.
Throwing athletic activity into the mix makes it even more serious.
You may need to increase your water and electrolytes since you lose more when you work up a sweat.
Try exogenous ketones
As a pre-workout supplement, exogenous ketones can enhance your performance.
Take a break
If needed, consider taking a rest from your athletic activities during your Extended Fast. There’s no shame in that.
Exercise for Average People (Non-Athletes) during an Extended Fast
If you already have an exercise routine before you start your fast, you can try to maintain it and see how it goes.
If you feel good, there’s no reason to change anything. But if you feel tired or unwell, you’ll need to scale back.
If you are not someone who was previously active, now is not the time to start something new! It can wait till after your Extended Fast.
A much better option is gentle exercise, such as walking.
In fact, if you are more than 40 pounds or so over your ideal weight, strenuous exercise can increase cortisol and sabotage your hard work.
Exercise during Intermittent Fasting
Working out or performing athletically during Intermittent Fasting is not as risky as during an Extended Fast.
Here’s a few tips to consider:
- Try scheduling your workouts around your eating window. Having your eating window open right after a workout is idea
- Again, if you are more than 40 pounds over your ideal weight, opt for gentle exercise such as walking
- Stay hydrated and keep your electrolytes on point. As with Extended Fasting, you might need to increase water and electrolytes if you are regularly working up a sweat
- Stop if you feel tired or unwell
Fasting and exercise can be great together!
Fasting and exercise are both supposed to improve your health, not make it worse.
As with all things, use common sense, and check in with your doctor if you feel unwell.