Recovery from Your WOD—with Microbes in Mind

Gastrointestinal issues and delayed onset muscle soreness (DOMS) can interfere with the CrossFit athlete’s performance. But new research shows that a healthy microbiome can significantly aid recovery from your WOD, and your whole-body health.

(Unit 3 of 7)

Recovery from Your WOD

Let’s face it: one appeal of CrossFit is overcoming physical discomfort and pain. You’re not in the box to relax. You’re there to join your fellow athletes in a ritualistic challenge that tests your limits every time, burn be damned. If it’s not uncomfortable, you’re doing it wrong. This is a sport whose unofficial mascot is named “Pukie,” after all

But any good instructor will tell you there are different kinds of pain — some you can push through, and some that require listening to your body, and working smarter, not harder. Gastrointestinal pain and delayed onset muscle soreness (DOMS) caused by your workout are two examples of the latter. 

All athletes, and especially those focused on resistance training like CrossFitters, are at increased risk of GI issues and DOMS. It’s likely you’ve experienced symptoms of one or both: gut cramps, diarrhea, or bloating after a workout, or swollen, painful joints that begin to appear a full 24 hours after your last front squat. Both have implications for your whole-body health, inhibit your performance and recovery from your WOD, and more simply, just suck.

But did you know that your microbiome — that’s the interconnected, incredibly diverse system of microorganisms that call your body home — can play an important role in minimizing the effects of both post-workout GI issues and DOMS? Here’s how these microscopic residents might help mitigate any issues you are having with recovery from your WOD.

Post-Workout GI Issues

Gutting It Out: Dealing with Post-Workout GI Issues

Fact: A single high-intensity workout can cause pain in your gut. Studies like this one show that 60 minutes of endurance exercise, or just 30 minutes of resistance exercise, can cause damage to the epithelial lining that covers more than 4,000 feet of your small intestine’s surface area and, unsurprisingly, plays an important role in digestion. That’s why athletes who work out longer and harder have an increased risk of experiencing symptoms such as cramps, diarrhea, bloating, nausea, and even intestinal bleeding.

Why is your intestinal barrier impacted by a workout? When you work out, your body reduces the blood flow to your gut, which can damage the gut’s lining. The blood shunted away from the gut goes to your glutes or gastrocs, or any other working muscle group (hence, the origin of the extra blood that gives your muscle a “pump”). Exertional heat stress — the general heat stress caused by exercise — has also been shown to compromise this intestinal barrier. When it’s not working correctly, your gut lining is more permeable, allowing pathogens and pro-inflammatory molecules to enter your bloodstream. Scientists and medical professionals often call this problem of increased permeability, when present over a sustained period of time, “Leaky Gut Syndrome.”

And it’s not just about pain — GI issues after a workout can affect your muscle repair and recovery. Studies like this one also show that this lack of blood flow, called “hypoperfusion,” of the GI tract following exercise can affect an athlete’s ability to digest and absorb post-workout nutrients. One such study showed that delaying carbohydrate and protein supplements 30 minutes, rather than 5 minutes, after an intense workout increased rates of gastric emptying and blood glucose levels. The point: try to delay your post-workout snack by at least 30 minutes — this may help your body’s recovery from your WOD.

Several other tactics can help the CrossFit athlete’s gut. Fluids and carbohydrates before and during a workout seem to offer protection to your intestinal barrier. Another good move? If you can, skip the non-steroidal, anti-inflammatory drug (which can cause adverse reactions to your GI tract) after your workout. Also, consider a probiotic (live microorganisms that, when administered in adequate amounts, confer a health benefit on the host) or prebiotic (nondigestible food components that stimulate growth of beneficial gut bacteria and confer a health benefit on the host), both of which can support the microbiome’s regulation of the intestinal lining. Some studies have demonstrated promising benefits for probiotic use on the athlete’s immune system, which might help minimize the negative effects of even an acute leaky gut. 

Delayed Onset Muscle Soreness (DOMS)

The Muscle-Pain Scapegoat: Debunking Lactate as a Cause of DOMS

Remember your first Filthy 50? The extreme pain you experienced 12-24 hours afterwards is called delayed onset muscle soreness (DOMS). DOMS is caused by a workout of unfamiliar intensity or duration, most often “eccentric muscle work,” when the muscles lengthen under tension. It is, as you know, not a lot of fun.

What causes muscle soreness after a workout?

But what causes DOMS, and all muscle soreness after a workout? For nearly a century, lactic acid, or lactate, has been blamed. Lactate is one of two possible end products when your skeletal muscle turns glucose into energy (the other being the less-maligned pyruvate). Lactate was discovered in milk in the 1780s, but it was physicians and biochemists Archibald V. Hill and Otto Meyerhof who tied it to skeletal muscle processes in the 1920s. They tied lactate production in the muscles to inadequate oxygen metabolism during activity — necessitating “anaerobic metabolism,” or the creation of energy in cells without oxygen, and causing acidosis, or an excess of acid in the blood.

Both of these things were bad signs for lactate, and appeared to be backed up by an increase in lactate in the blood at a certain point during physical exercise, termed the “lactate threshold.” And so it is that you know lactate and lactic acid as a bad byproduct of exercise, the cause for muscle pain, cramps, and fatigue.

These dogmatic tenets are simply untrue. There is little evidence that muscles ever become anaerobic during exercise; lactate is actually being constantly made and oxidised by your body, even when you’re not exercising; and scientists determined long ago that blood and muscle lactate concentrations return to resting levels within an hour of an exercise session. And then there are those rare persons (McArdle’s disease; about one in 100,000 persons have this) that lack a muscle enzyme and therefore are unable to break down muscle glycogen (the storage form of carbs in muscle). This means they cannot make lactic acid, at rest or during exercise, yet they experience acute and delayed onset muscle “burn” and soreness, respectively (and have greatly compromised exercise tolerance). All of this makes it highly unlikely that lactate causes delayed pain and stiffness after exercise. In fact, lactate plays an important part of your body’s creation of energy and recovery process. Biochemists’ “new” ideas about lactate come from the Lactate Shuttle Theory. Here’s how it really works: your fast-twitch skeletal muscle fibers produce lactate out of glycolysis, from glucose (which arises from muscle glycogen, or uptake from the blood). That lactate travels through your bloodstream to remote or local slow-twitch muscle fibers, and other active and inactive tissues, including your heart, where it’s “recycled”  into pyruvate and used as a substrate for aerobic respiration. It’s not an ugly byproduct — it’s fuel!

Lactate & Recovery from Your WOD

There’s even more benefit to lactate. The consumption of probiotics and probiotics can increase lactate’s appearance in the gut, where it can act as an anti-inflammatory mediator, promoting the health of your gut mucosa — part of that intestinal lining that takes a hit every time you exercise. 

As for DOMS and most other post-workout pain — it’s most likely caused by microscopic tears in the muscle fibers, which is like catnip to immune cells, who then home in on the damage and release a tsunami of pro-inflammatory chemicals. Rest, ice packs, painkillers, and massages can all help alleviate post-workout muscle pain. So can a gradual start to new workouts and improve recovery from your WOD. Pukie wouldn’t be proud, but then again, you know best when to work smart, not hard.

Curiosity is rewarded.

If you are reading this, we have a challenge for you—take this quiz. Correct answers may earn you (what we call at Seed) magic.


Also Check Out…

The Microbiome and Your WOD (Unit 1)

What’s Going on Inside Your Gut – What Athletes Need to Know (Unit 2)

Planting the Seed for a Healthy Microbiome (Invictus Mindset Podcast w/ Guest Raja Dhir)


About the Author:

Anthony L. Almada, MSc, FISSN is a member of the research and development team at Seed, which develops probiotics to impact human and planetary health. He is trained as a nutritional and exercise biochemist (UC Berkeley). He has been a co-investigator on over 50 university-based clinical trials exploring the effects of diet, dietary supplements, and therapeutic interventions upon muscle performance, body composition, whole body metabolism, and joint function in health and disease. In 1990 he created the “thermogenic” category. In 1993 he co- founded the first company to introduce creatine monohydrate to North America. He has worked with CF Games and Regional athletes, top Olympic gold