Sleep, Exercise, and Your Gut


Have you ever had a particularly hard workout, maybe on a really hot day, and not been able to fall asleep that night? Well, knowing how intense exercise can affect the gut and in turn the immune system, it’s not a far stretch to grasp how the two can affect sleep – too much of a good thing can cause problems.

Low to moderate levels of exercise have been shown to improve just about everything health related in humans. It’s when exercise becomes more intense that the water gets murky and the health benefits are less clear (see the latest on exercise and heart health). Sleep and intense exercise does not appear to be any different.

We know that during intense or long periods of exercise the gut can become more permeable, or “leaky.” This process can lead to endotoxemia and in turn a cascade of inflammation (heat, poor nutrition, NSAIDs all increase this effect). Blood markers of inflammation are found to be elevated during this process. Studies have demonstrated that administration of higher levels of these inflammatory proteins can disrupt NREM sleep and increase wakefulness, whereas lower levels appear to improve sleep.

The mechanism by which these inflammatory markers affect sleep is thought to be related to their influence on the hypothalamic-pituitary-adrenal (HPA) axis, which helps mediate the body’s response to stress. It has also been shown that there are receptors for these proteins in the brain. So it appears the inflammatory proteins exert their effects both in a direct (central neurons) and indirect (HPA axis) manner.

Although, the exact progression of these events is not entirely clear it does appear likely that intense levels of exercise, including duration, can affect sleep through the disruption of gut integrity. This emphasizes the need to maintain optimal gut health through proper nutrition and recovery from exhaustive exercise.

Another mechanism being investigated involves the microbes of the gut and their influence on the brain and specific functions like sleep. We already know that these little bugs even release their own hormones like GABA and serotonin! There is no doubt that exciting research is currently being done on these mechanisms and we can’t wait to see what kind of impact it will have on athletes and training – stay tuned!

Diet and your gut health


Our guts are home to trillions of bacteria, some good, some bad. What is most certain is that they have a tremendous impact on our health. These organisms in our gut, or intestinal microbiome, can be influenced by several factors including where you live, stress, and alcohol. But it is believed that our diet has the greatest impact on our gut’s microbiome. Disruption of this delicate system has been linked to an array of maladies including obesity, diabetes, and depression. More and more research is demonstrating that these bacteria have a far greater influence on our general health than we thought.

The traditional Western diet consisting of high fat, high protein, and more than a modest amount of alcohol has been shown to alter the gut’s microbiome in a negative way. The Western diet leads to alterations in the gut’s protective function. Because of this, toxins leak from the gut and into our bloodstream resulting in low grade inflammation. The Western diet has been linked with cardiovascular disease and diabetes – both associated with increased levels of inflammation in the body.

Most research has compared the traditional Western diet with vegetarianism, which not surprisingly is not associated with leaky guts and inflammation. But if you’re reading this you’re probably not eating fast food or buying your groceries at places that also sell clothes and lawn supplies. You may adhere to the Paleo diet, or even be strictly vegan. Although, we know that these diets affect the composition of the gut microbiome I have yet to find research that compares their influence on the protective and more beneficial bacteria of the gut (if you are aware of such research, please share it with us!)

Although, there have been studies showing that high protein and high fat diets contribute to alterations in the gut’s microbiome that result in inflammation and even colon cancer, the types of protein and fats the studies were using are not characteristic of a Paleo diet or any other (non-Western) that focuses on high fat and high protein. There is clearly a difference between lard (used in one comparative study) and the fat found in almonds and avocados.

I think the common thread that connects all “bad” diets is not necessarily a food group, but rather how processed it is, in other words, how far removed is it from it’s original natural source. What is most important for our gut health, in my opinion, is not the food group we consume most of but whether it is real–whole foods. As this article from Nature points out, our bodies have learned to adapt to various diets:

Our findings that the human gut microbiome can rapidly switch between herbivorous and carnivorous functional profiles may reflect past selective pressures during human evolution. Consumption of animal foods by our ancestors was likely volatile, depending on season and stochastic foraging success, with readily available plant foods offering a fallback source of calories and nutrients. Microbial communities that could quickly, and appropriately, shift their functional repertoire in response to diet change would have subsequently enhanced human dietary flexibility.

What is clear is that our body’s adaptation to the modern diet is anything but adaptive. Ultimately, you need to determine what foods are best for you knowing that your gut’s microbiome is influenced by many factors including genetics, where you live, but most importantly your diet. Perhaps, less attention needs to be on whether one specific diet is better, and simply focusing on eating real food – as Jennifer Aniston said “just stop eating shit.”


When being an athlete isn't so healthy


As an endurance athlete, you are constantly pushing yourself to the next level. While many of your friends and coworkers are still in bed, you are on the road or in the water working to squeeze in that extra mile or two of training in hopes of shaving even a fraction of a second off of your time on race day. Unfortunately, you may have noticed that your physically demanding lifestyle has started to affect your health. You may have also wondered why it seems so many elite athletes drop out of races from “infections.” There is a scientific reason why athletes are more susceptible to illness. Below we will explore the reasons for this and what you can do to stay healthy so you can keep on striving for greatness.

Whether you are biking, swimming, or running, the harder you train, the higher your risk for infections. One study found that elite triathletes and cyclists have a higher incidence of upper respiratory infections (URIs), with the common cold being the most frequent. Additionally, research suggests that this increased risk for URIs may be due to a weakened immune system in athletes.

Why do endurance athletes have impaired immune function? If you read our article, “What Athletes Need to Know About Leaky Gut”, you may remember that intestinal permeability increases with exercise intensity. This increased permeability may cause substances to “leak” from the gut into the bloodstream, a process called endotoxemia, and weaken your immune system. While the exact mechanism is currently being investigated, prolonged exercise has also been found to lower the levels of immune cells.

Does this mean you have to choose between your health and your training? No way! Along with proper hydration, sleep, and optimal nutrition there are ways to help prevent the potential side-effects of intense training. Probiotics have been shown to boost the immune system and are a fantastic tool to add to your training repertoire. Specifically, probiotics reduce the frequency of URIs in endurance athletes and increase markers for immune system function. Are URIs not an issue for you? Probiotics have also been found to reduce exercise-induced gastrointestinal (GI) symptoms.

As an endurance athlete you need to optimize every element of your training, on the road as well as off. Bottom line: stay healthy – finish strong!

by Katelyn Collins

Katelyn Collins, is a future registered dietitian with a passion for probiotics, a knack for nutrition communications, and a love of athletic pursuits on both land and sea.


What athletes should know about leaky gut


You have probably heard the term "leaky gut" before, but what does the science actually say  about this phenomenon and how does it relate to endurance athletes?

When we talk about leaky gut, we are really referring to an increase in intestinal permeability. This does not mean that there are holes in the intestines, but rather that the spaces between the cells that make up the intestinal lining have widened. Normally, intestinal cells are closely packed next to each other to form tight junctions that only let small molecules pass from the intestines into the bloodstream. During times of increased permeability, the tight junctions loosen giving larger molecules and toxins the opportunity to leak into the bloodstream.

Increased intestinal permeability is a particularly important issue for endurance athletes because exercise has been shown to draw blood flow away from the gut which increases permeability and may lower the efficacy of the immune system. This can lead to common side effects that many endurance experience such as cramps, diarrhea, nausea, and an increased risk of infection. One study found that permeability increases with running intensity so the harder you train, the higher your risk for these adverse effects. But don’t worry, no one is telling you to lighten up on your training! There is actually a way to help prevent the exercise-induced increase in permeability: probiotics.

Probiotics have been shown to prevent intestinal permeability and even prevent exercise-induced permeability specifically. The idea is that probiotics form a protective barrier around the intestinal cells which reduces permeability and supports the immune system. This may explain why probiotic supplementation is associated with fewer gastrointestinal and respiratory illnesses in athletes.

Probiotic supplements are a great tool to help you stay healthy while training hard, but be sure to choose your probiotic wisely. If you read our post on why probiotic strains matter, you will remember that a probiotic should contain the types that have been shown to result in the benefits you are looking for you.

by Katelyn Collins

Katelyn Collins, is a future registered dietitian with a passion for probiotics, a knack for nutrition communications, and a love of athletic pursuits on both land and sea.


Is your frame stronger than your bones?

Image Source:  Cycling Weekly

Image Source: Cycling Weekly

One of the greatest cyclists to ever race in the professional peloton crashed out of the Tour de France yesterday. Fabian Cancellara was wearing the yellow jersey when he was involved in a high speed crash that took out several riders. Unfortunately, Cancellara did not ride away unscathed. He suffered fractures of his lumbar spine, effectively ending his Tour and the rest of his season.

Broken clavicles are a frequent occurrence among competitive cyclists. But broken bones of the spine? That usually happens in little old ladies, right?! Granted, Cancellara was likely racing at over 30mph and landed directly on cement, the accident got me thinking, are cyclists at risk for poor bone health?

I already had a good idea of the answer, but I wanted to dig into the research a bit more. Although, cycling has been shown to confer several health benefits, improving bone health is unfortunately not one of them. News Flash: cycling is a non-weight bearing activity and as a result it is associated with lower bone mass. In fact, two-thirds of the professional and master adult road cyclists could be classified as osteopenic, or having a bone density lower than normal. Many times it is the lumbar spine, or lower back, that is found to be osteopenic. This is the part of the spine that was fractured in Fabian Cancellara’s case.

Interestingly, calcium intake and hormonal influences on bone health, were found to be within normal ranges in the cyclists studied, suggesting that it is the lack of impact on the bones that leads to the low density. 

Speaking from experience, when you are really training and racing hard the last thing you want to do is exert more energy off the bike, so what do you do? You put your feet up and lie on the couch all day further reducing the needed stress on your bones to maintain their density.

Although, we don’t know if Fabian Cancellara has osteopenia, I’d be willing to bet that many cyclists in the elite and professional pelotons do. With a high incidence of crashes in road cycling, bone health is not a topic that receives it’s needed attention. And the research is pretty darn clear: those of us who compete in road cycling are more likely to develop osteopenia and osteoporosis.

So do we add in weight training to prevent bone density loss? For many cyclists this is an absolute no-no. If that’s the case for you, other forms of resistance training can be added instead, including pilates and plyometrics. Interestingly, it does appear that mountain biking, with its more impactful riding, is not associated with as much bone density loss.

It’s also important to think about getting screened for osteopenia if you consider yourself a competitive road cyclist. Screening would include a few lab test including hormone levels, calcium, and Vitamin D, as well as a bone density scan, or DXA (fyi: when you tell your doctor that you want to be screened for low bone density he or she will laugh at you, assuming you don’t have the normal risk factors for osteopenia, and rattle off what the USPSTF recommends and try to send you on your merry way. At that time please take out your phone and show him or her the link to this study and then politely ask again for a DXA).

It was a sad day, losing Fabian Cancellara to a crash just as he had donned the leader’s yellow jersey. He will be back, better than ever I’m sure. To make sure you’re able to bounce back from injury too, and perhaps prevent it from occurring in the first place, consider checking on the status of your bone health...or just go get yourself a mountain bike!