March 30, 2016
If you’re a serious runner, you’ve likely seen The Jericho Mile, a 1979 Emmy-Award winning film about Larry Murphy — a Folsom State Prison inmate with a 3:52 mile and a shot at the Olympics. About three-quarters of the way through the movie — as Murphy contemplates his first big race in the cafeteria — another inmate gives him a bowl of melon and a bit of advice: “Fruit’s good for you, man, eat plenty of fruit.”
Mic drop. If only Murphy had listened.
Odds are you’ve been ignoring the same advice your entire life. Your mom nagged you about eating your broccoli and Brussels sprouts. Your doctor advises you to “eat the rainbow.” And you likely have at least one vegan friend who wants to convert you — or at the very least replace some of the meat in your largely carnivorous diet with plants. Even Michelle Obama got in on the act, imploring you and every other American to eat more fruits and veggies. And like Murphy (and most other Americans), odds are you don’t listen: Only 1 in 10 people in the United States eat the recommended five servings of fruits and vegetables a day, according to a recent report from the CDC.
That’s a problem. “If you’re not eating at least two servings of fruits and three servings of vegetables per day, you’re not building ‘foundational health,’ which is key for preventing disease and supporting athletic performance,” says Susan Kleiner, PhD, R.D., author of The Powerfood Nutrition Plan. If she had her way, you’d eat eight servings.
While nutritionists have long known about the athletic advantages of increasing protein intake, they’re only just beginning to comprehend the fitness benefits of eating more phytonutrients — bioactive (i.e., body-boosting) compounds found in fruits, vegetables, grains, and other “phyto” (plant) foods. You’ve likely heard about the most popular ones, including resveratrol, lycopene, and even curcumin. But more than 5,000 others have been identified in the more than 150,000 known edible plants, and many scientists estimate that the bulk of phytonutrients — and their benefits — have yet to be discovered.
“One of the most exciting benefits of phytonutrients is their strong antioxidant potential, disarming free radicals that wreak havoc in the body,” says Kleiner. “But it’s also bigger than that—scientists are learning that some phytonutrients seem go deep into the genetic matrix, turning on and off genes that protect us from disease development.”
That potential of phytonutrients to bolster the immune system is hugely important for athletes, who often run themselves down through overtraining. “One of the biggest things that holds athletes back is getting sick, and research shows that some phytonutrients can act as prebiotics, stimulating the growth of bacteria in your gut, thus helping to boost immunity,” says Kleiner.
Polyphenols — found in abundance in green tea — are among them, according to Japanese researchers. In their study, they found that green tea not only acted as a prebiotic, but also altered the balance of intestinal flora, inhibiting the growth of “bad” bacteria (e.g., Clostridium difficile, C. perfringens, and Streptococcus pyogenes), and promoting the growth of “good bacteria,” like Bifidobacterium and Lactobacillus.
But perhaps the greatest benefit of phytonutrients — especially as far as athletes are concerned — is their ability to fight exercise-induced inflammation. “The nature of training is to tear the body down, and the body is extraordinary in its ability to repair and rebuild its tissues to become stronger,” says Kleiner. “But part of that process involves an inflammatory response — inflammatory cells rush to the damaged tissue, heat it up, and begin repairing it.”
If you’ve ever felt sore a couple of days after a tough workout (a phenomenon known as delayed onset muscle soreness, or DOMS), you’ve felt the inflammatory process at work. A little inflammation is a good thing — it helps your muscles adapt to the demands of training (and you to become more powerful). “But if you don’t have enough anti-inflammatory factors in your body, the inflammation process can proceed unchecked, which can delay recovery,” says Kleiner.
Two phytonutrients have proven particularly efficient at checking this type of inflammation: Pomegranate (which you’ll find in Beachbody Performance Recharge) and tart cherry (which is one of the key ingredients in Beachbody Performance Recover). In a study at the University of Texas, participants who drank pomegranate juice experienced 25 percent less soreness two hours after working out than the placebo group. They were also 10 percent stronger two days later. Similar pain-fighting and inflammation-reducing results were reported for tart cherry extract in a study at Winona State University.
The list of potential benefits from phytonutrients grows almost monthly as new studies are published. “Researchers are even starting to find that certain phytonutrients can boost mental focus and recovery, which are huge for athletes during a race or toward the end of a workout,” says Kleiner.
Consuming resveratrol (found in red wine and chocolate), for example, can enhance memory retention and neural communication, according a recent study in The Journal of Neuroscience. Ditto for flavonoids (found in countless fruits and veggies, as well as green tea), which also exhibit neuroprotective properties, according to research at the University of Reading, in England. “In all likelihood, every single plant has benefits — both for general health and athletic performance,” says Kleiner.
Fortunately, you don’t have to eat every single plant to reap the benefits; you just have to eat a variety of them, according to Kleiner. “And by variety, I mean not only among food groups, but also within food groups,” she says. In other words, while you might love bananas, Amaranth, and Swiss chard, don’t just eat bananas, Amaranth, and Swiss chard. Becoming stuck in a dietary routine is just as detrimental as getting stuck in training rut.
“Every day, I would like you to have one serving from the citrus family, one serving from the berry family, and one serving from at least one other,” says Kleiner. An apricot or a slice of cantaloupe perhaps? Both contain carotenoids — phytonutrients that exhibit antioxidant-like properties.
On the veggie side, Kleiner recommends daily servings from the cruciferous family (broccoli, cabbage, brussels sprouts), allium family (onions, garlic, leeks), and the leafy greens (lettuce, kale, arugula). “Generally speaking, the more deeply or more brightly colored the fruit or vegetable is, the more potent its phytochemical content,” says Kleiner. And don’t forget whole grains. Quinoa, for example, is packed with quercetin and kaempferol, flavonoids have been shown to act like antioxidants and anti-inflammatories.
In short, your mom, doctor, and vegan friend were right — you should eat a greater number and variety of colorful fruits and vegetables. “And whenever possible, skip pills for whole foods,” says Kleiner. “There’s a lot we have yet to discover about phytonutrients, but one thing we do know is that they’re more potent when they work synergistically with other nutrients in foods than when they’re taken [and working] alone.”
November 25, 2015
Regardless of their athletic prowess, most people intuitively understand physical fatigue (or at least the basics of it). Simply put, it’s the inability to maintain power output—the point at which you can no longer pedal your bike fast enough, swing the kettlebell high enough, or find enough oomph to glide past other swimmers in the pool. You might start out strong, but after a while you… just… slow… down. That kettlebell might as well be a Fiat given the likelihood of you lifting it again.
When that happens, we usually blame our muscles for giving out, and that’s a distinct possibility. From glycogen depletion to acidification, plenty of things can contribute to localized muscle weakness. What a lot of people don’t realize is that physical fatigue can also be a symptom of a larger issue. It might feel like your legs quit after too many burpees, but the problem might not be your quads—something else might be going on that keeps your entire system from living up to its potential.
One possibility is a phenomenon called central nervous system fatigue (also known as CNS fatigue or plain ol’ central fatigue). The theory is that overtraining symptoms—including chronic fatigue, reduced athletic performance, and longer-than-usual recovery times—can stem from wear and tear on the complex of nerves in your brain and spinal cord (i.e., your CNS) that control the movements of your body.
You can think of your CNS as a city electric grid and your muscles as factories in the suburbs that demand a disproportionate amount of energy. Eventually, their demand overwhelms their power lines, causing local power failures and system-wide energy shortages. Even if your muscles wanted to sustain their output, they can’t because their power supply is compromised. Scientists demonstrate this phenomenon in the lab by stimulating a muscle’s motor nerve directly, producing induced contractions that are stronger than the subject’s voluntary ones. The takeaway: There’s more potential for muscular work than the brain can muster. In practice, such fatigue manifests as a lazy, sleepy, overall weakness that kills the motivation to lace up despite (in theory) having received enough rest.
While central fatigue is an extremely viable explanation for overtraining issues, it does have a checkered history. Experts spent much of the 1990s misidentifying and over-blaming it for poor athletic performance (sort of like the sports equivalent of fibromyalgia and chronic fatigue syndrome). But central fatigue is not just slang for feeling bad or having an off day at the gym. Numerous studies have confirmed that something, or more likely some things, potentially interfere at a cellular level with athletic performance following sustained exertion or excessive training.
Central fatigue should not be confused with peripheral fatigue. According to Emma Ross, head of physiology at the English Institute of Sport, when it comes to peripheral fatigue, “we’re talking about a reduction in the muscle’s ability to generate force.” This reduction can be due to any number of physical processes, such as the buildup of lactic acid or the depletion of fuel stores. The key is that it’s happening in the muscles themselves. Central fatigue, by contrast, is marked by impairments happening upstream of the neuromuscular junction. In other words, problems occur before the nerves even connect to the muscles in question.
Ross and her team have found that central fatigue can torpedo performance by 15 percent. In practical terms, that means your competitors have a 15 percent advantage if they avoid it and you don’t. “It is now really well established that central fatigue happens,” says Ross. “And it occurs because exercise—particularly continuous, prolonged, high-intensity, endurance-type exercise—elicits changes in the excitability of the motor cortex and in the brain’s ability to drive the muscle fully.”
Exactly how strenuous exercise causes those changes is a matter of debate. The most accepted theory was outlined in a study by Belgium researchers in the journal Sports Medicine. The short version is that it involves an uptick in levels of the sleep-related neurotransmitter serotonin (5-HT) brought on by a drop in blood levels of branched-chain amino acids (BCAAs), as happens during exercise. There’s a cascade of biochemical processes that explain why this could be so, but suffice it to say that while it may not be the whole story, the shifting BCAA-5HT ratio seems to be a key component.
There’s also some debate as to whether central fatigue is even a bad thing. After intense effort, the condition could simply be the body’s way of throwing up a caution sign and forcing us to cool our jets before we inflict serious (and perhaps permanent) damage on ourselves.
The situation also becomes a bit tricky in competitive sport, particularly in endurance activities like running, cycling, rowing, and swimming, all of which involve pushing physical limits to achieve a new, superior level of “normal.” What’s needed in endurance training is a controlled approach to such redlining so you don’t fry your circuits. Broadly stated, working at or near your max regularly but infrequently is a good thing, but doing so too often will take a toll.
“There is some central fatigue that occurs with almost every strenuous exercise session, but this usually goes away relatively quickly,” says Mark Davis, Ph.D., director of graduate programs in applied physiology at the University of South Carolina, Columbia. It’s more pronounced with extreme workouts/competitions, such as marathons, triathlons, or three-day combat missions, but the body usually does a decent job of dealing with it. You might take a little longer than usual to recover fully—especially if tissue injury is involved—but recover you will.
For competitive athletes, this is an expected part of training, says Davis. But if that training isn’t managed properly, it can quickly shift from an acute issue to a chronic problem with the athlete stuck in a perpetual cycle of central fatigue. That not only makes training suck, but it’s also a real bummer on race day.
How do you avoid becoming a fatigue slave? The first steps are creating an intelligent, periodized training plan, logging enough hours of sleep, and prioritizing. You can also mitigate the risk with a few key diet modifications. If scientists are right about the serotonin connection, eating sufficient carbs and BCAAs as you train should help keep your brain from taking on too much of the sleepy stuff. Good BCAA sources include whey and casein proteins, beans, beef, chicken, and soy. A dash of caffeine and maintaining normal blood glucose levels also helps, as does tweaking your diet to fight inflammation (e.g., by increasing your consumption of fruits, vegetables, and omega-3 rich fish, and reducing your intake of refined carbs and trans fats). Some supplements can also help, including quercetin, which studies suggest is a potent anti-inflammatory.
Overall, David believes, central fatigue is for the most part inevitable. Nearly everyone who performs intense workouts with will experience it. But with appropriate training, rest, and nutrition, it doesn’t have to get in the way of achieving your goals.
October 21, 2015
How much endurance do your muscles really have? Try sprinting around a track for as long as possible. I promise you won’t be able to keep this up for more than a few minutes or a couple of laps. Why? Because your body simply can’t produce enough energy to fuel such a high level of intense activity for very long. But you can improve how hard you can go and how much you can accomplish before your muscles give out. One obvious way is training. Another is proper supplementation. And one supplement that’s garnering a lot of attention in that regard is beta-alanine.
To understand how this amino acid works, it helps to know a bit about how it functions in the body.
A Quick Rundown on Energy Production
Adenosine triphosphate (ATP) is the body’s go-to energy source, and it can be created by any of three different systems. The one that’s used depends on the intensity and duration of exercise.
At one end of the energy production spectrum is the phosphagen system, which metabolizes creatine phosphate to support short bursts of intense activity lasting up to about 10 seconds. If you do a 100-meter sprint or perform a barbell snatch, that’s the system you use. At the other end of the spectrum is the oxidative system, which uses oxygen along with carbohydrates, fats, or even proteins to support low intensity activity lasting longer than 2 to 3 minutes (think: aerobic endurance). If you’re a runner, this is where you live.
However, right in the middle there is the glycolytic system, which metabolizes muscle glycogen to create ATP. This is the predominate system relied upon during intense activity lasting from 10 seconds up to around 2 minutes (e.g., interval training). However, one of the main metabolites (a product of metabolism) of this process is lactic acid. The body can process a certain amount of lactic acid, but when it cannot keep up with the high production during prolonged glycolysis (i.e., using glucose for energy), like during the 800-meter dash or a round of boxing, tissue becomes acidified and muscles begin to feel fatigued and “pumped.” This eventually results in muscular failure.
Carnosine buffers muscular acidification thus helping to prolong the glycogen system’s ability to generate energy. The body stores carnosine in muscle tissue and releases it into the system when muscle pH begins to drop. Increased concentrations of muscular carnosine have been linked with increased muscular endurance. So for those of us that want to improve our ability to engage in intense exercise for longer periods of time, more carnosine seems to be a very good thing. So we should all start taking carnosine supplements, right? Well, not quite.
A More Efficient Method
Carnosine is a dipeptide (i.e., two amino acid) protein comprised of beta-alanine and L-histidine. When carnosine is consumed, either in supplement form or from natural sources like animal proteins, it is broken down into these constituent aminos. Beta-alanine and L-histidine are then transported into muscle cells, where they are recombined to form carnosine once again. However, beta-alanine is the rate-limiting factor here, meaning you generally have access to less of it than you do of L-histidine (I know, the math doesn’t seem to add up, but trust me on this). So when dietary carnosine is consumed, only a portion of it is productively used to generate carnosine in muscle tissue. As a result, the most efficient way to produce muscular carnosine is to simply ingest beta-alanine on its own.
How to Use Beta-Alanine
The goal of beta-alanine supplementation is to maximize carnosine concentration in muscle tissue throughout the body. Current research indicates that an ideal strategy is to take 1,600 mg a day in two 800 mg doses (although 1,600 mg at once is acceptable, too). Because it takes time to elevate carnosine concentration, results typically occur after 1 to 2 months of daily use.
The only common side effect from beta-alanine consumption is a harmless, but potentially uncomfortable symptom called paresthesia. It’s characterized by a tingling sensation throughout the body, and most often occurs with higher doses (although some people experience the symptom with doses as low as 800 mg). If you experience paresthesia, try taking several smaller (i.e., less than 800 mg) doses of beta-alanine throughout the day instead of one or two large ones.
Focused training will, of course, improve and extend muscular endurance. But research seems to show that supplementing with beta-alanine may also improve the body’s ability to produce the energy necessary to fuel intense activity. More output means bigger gains in the gym — and stronger performance in your sport of choice.