We’ve probably all read an article or two that talks about inflammation and it’s various consequences, but what is inflammation? Historically, inflammation was defined as: redness, swelling, heat, and loss of function. However, with advances in molecular biology, we have since come to understand that inflammation is the combined result of numerous signalling particles in the body that activate the immune system. These signalling particles, known as cytokines, can have either pro-inflammatory or anti-inflammatory effects depending on which specific particle is in circulation. Originally, it was thought that these cytokines do not cross the blood brain barrier, but research has now shown that the pro-inflammatory cytokines can enter the brain and cause inflammation within the brain. This in turn is thought to cause a number of changes in behavior that are collectively called “sickness behavior.” One of these changes seems to be a decrease in physical performance or fatigue. For the ultra-distance athlete, this is important because these pro-inflammatory cytokines are given off by by muscle and immune cells during an extended endurance activity. They can then prevent the brain from fully activating the muscle, leading to less force and slower running times. We are currently working on a product to reduce this inflammation so you as the runner can maintain your running pace longer during your race. In my next post, I will attempt to explain the current strategies for reducing inflammation and why they may or may not be beneficial to you as an athlete.
Under normal conditions of exercise the body has two main sources of fuel: fat and carbohydrate (CHO). The According to Jeukendrup 2003, the body has roughly 2000 kcal of stored CHO, stored primarily as muscle glycogen. If we assume that an average person would expend ~100 kcal per mile of running, then this would translate to ~20 miles of running(Jeukendrup, 2003). In contrast, the Jeukendrup 2003 reports that the human body stores roughly 106,000 kcal of fat, primarily in adipocytes (100,000 kcal) and secondarily as intramuscular triacylglyceride (2600 kcal) (Jeukendrup, 2003). Theoretically, there are several possible benefits to increasing reliance on fat oxidation. As previous research has shown that glycogen availability may impact force generation by modulating sarcoplasmic reticulum (SR) calcium release (Ørtenblad, Nielsen, Saltin, & Holmberg, 2011), sparing muscle glycogen by oxidizing more fat may preserve force generation. In order to be metabolized, fat is mobilized from triglyceride storage and delivered to the mitochondria as free fatty acids (Horowitz & Klein, 2000). Fatty acids are then broken into 2 carbon fragments in the form of acylCoa. During this process one FADH and one NADH are generated, but no direct rephosphorylation of ADP to ATP occurs. Unlike oxidation of glucose, fat oxidation requires more flux through the oxidative pathways since generation of ATP is nearly exclusively through the electron transport chain (ETC) (Gropper & Smith, 2012). Since there increased flux through ETC there may be a training effect to increasing reliance on fat as a fuel source (Miller, Bryce, & Conlee, 1983; Simi, Sempore, Mayet, & Favier, 1991).
Several studies on rats have provided encouraging data that high fat diets may improve endurance capacity through stimulating increases in oxidative enzymes and preservation of muscle glycogen stores (Conlee et al., 1990; Miller et al., 1983; Simi et al., 1991). Miller et al., 1983 showed that a high fat diet reduced muscle glycogen and liver stores, but also improved exercise capacity and oxidative enzymes (Miller et al., 1983). Simi et al., 1991 provided evidence that while training may blunt this effect, there is still an effect on oxidative capacity for a high fat diet after training in rats. However, it is possible this effect could disappear if the training stimulus were high enough since the training stimulus used was quite small (Simi et al., 1991). Conlee et al., 1990 may suggest there is added benefit to fat adapting a rat and then transiently increasing CHO prior to exercise (Conlee et al., 1990).
It is important to understand that while these results are encouraging, human studies have had less positive results (Horvath, Eagen, Fisher, Leddy, & Pendergast, 2000; Rowlands & Hopkins, 2002; Vogt et al., 2003). This may be in part due to the large variation in diets deemed high fat in human studies. The animal studies tended to have fat intakes around 70% of the diet, whereas high fat diets in human studies have ranged from 44-70%. It appears there may be two defined diets based on the literature. The first diet deemed high fat is based on increasing fat intake beyond the recommended 20-35% of calories (“Nutrition and Athletic Performance,” 2009). These diets tend to have a higher proportion of fat, but maintain a substantial contribution from carbohydrates (Horvath et al., 2000; Rowlands & Hopkins, 2002; Vogt et al., 2003). The other version of the high fat diet is additionally very low carbohydrate (Goedecke et al., 1999; Lambert, Speechly, Dennis, & Noakes, 1994). Such a large range of diets classified as high fat may be partly responsible for the mixed results. In support of this, Lambert et al., 1994 found that a diet of 70% fat significantly improved time to exhaustion at 60% of VO2max. However, time to exhaustion at 90% VO2max and CHO oxidation rates at high intensity were unaltered (Lambert et al., 1994). Goedecke et al 1999 used a high fat diet, 69 ± 1% fat, for 15 days (Goedecke et al., 1999). Carnitine acyl transferase activity was significantly increased within 5-10 days of being fed a high fat diet. However, 40 km cycling time trial performance was not significantly different compared with a high carbohydrate diet. Taken together, it appears that a high fat, low carbohydrate diet may have beneficial effects at moderate intensity activities, but when intensity is increased beyond a certain threshold, the working muscles will still shift to burning almost exclusively carbohydrate. After this shift occurs, there is likely no performance benefit to a high fat diet.
Early studies on high fat diets focused on the metabolic consequences of such diets which were shown to induce obesity in animal models (Mašek & Fabry, 1959). In fact, a number of studies have shown that high fat diets can induce metabolic syndrome and insulin resistance (Ikemoto et al., 1996; Oakes, Cooney, Camilleri, Chisholm, & Kraegen, 1997; Todoric et al., 2006; Tschöp & Heiman, 2001). However, it should be noted that the type of fat used in the diet can have an impact on this outcome. Particularly, Ikemoto et al. 1996 found there was a positive association between linoleic acid intake and plasma glucose, and that a diet high in fish oil actually had beneficial effects on body weight and glucose uptake. Other studies have suggested there is a beneficial effect on health for diets high in fish oil (Buettner et al., 2006). It appears there may be a gap in the literature on the long term consequences of high fat diets in combination with endurance exercise. In light of this, it would be prudent to recommend athletes attempting to alter substrate utilization through a high fat diet should consume most of their fats from sources shown to not adversely affect glucose uptake.
Literature on high fat diets and exercise performance that account for types of fat seem to be scarce. However, there have been a number of experiments examining medium chain fatty acids as a potential energy source during exercise. Medium chain fatty acids are described as fatty acids with 6-10 carbons that readily cross the mitochondrial membrane where medium chain acyl CoA synthases activate them before they are oxidized (Marten, Pfeuffer, & Schrezenmeir, 2006). The rationale would be to supplement with the medium chain fatty acids just prior to or during exercise to provide an energy source during exercise (Angus, Hargreaves, Dancey, & Febbraio, 2000; Jeukendrup, Saris, Schrauwen, Brouns, & Wagenmakers, 1995). However, as pointed out by Jeukendrup et al. 1995, the GI tract has a low tolerance for medium chain fatty acids during exercise, which may limit its usefulness as an ergogenic aid.
It is currently unclear why someone might recommend a high fat diet for strength performance. Anecdotally, numerous books promote “paleo” diets which tend to be low carbohydrate, higher fat, for numerous athletic populations (Burnett, 2012; Outram, 2014; Smith, 2012). Many of these books claim that humans evolved to eat only meat based on little or no actual research. However, some studies have attempted to examine early human diets, but found that early humans likely ate a mixed diet with slightly increased protein and decreased fat intake (Nestle, 2000), while other studies contradict this finding suggesting diets were high in fat and low to moderate in carbohydrate (Eaton & Eaton Iii, 2000). Studies on modern indigenous tribes suggest there may also be a larger role for dietary fiber for such populations (Johns, Nagarajan, Parkipuny, & Jones, 2000). It may be that early humans had a large range of diets depending upon food availability and regional culture. It should also be noted that it is currently unclear whether early humans were any healthier due to their diets (Nestle, 2000). One study suggests that the stereotypical “caveman” diet would be lethal to pregnant women and their fetuses (Hockett, 2012), suggesting that these diets may differ from popular conception. It appears there is very little literature on using a high fat diet to improve performance for strength athletes. However, high fat meals have been shown to reduce total and free testosterone (Cano et al., 2008; Volek, Love, Avery, Sharman, & Kraemer, 2001), but it is unclear whether these reductions in androgens would be large enough to affect adaptation to strength training.
Angus, D. J., Hargreaves, M., Dancey, J., & Febbraio, M. A. (2000). Effect of carbohydrate or carbohydrate plus medium-chain triglyceride ingestion on cycling time trial performance. J Appl Physiol (1985), 88(1), 113-119.
Buettner, R., Parhofer, K., Woenckhaus, M., Wrede, C., Kunz-Schughart, L., Schölmerich, J., & Bollheimer, L. (2006). Defining high-fat-diet rat models: metabolic and molecular effects of different fat types. Journal of molecular endocrinology, 36(3), 485-501.
Burnett, K. (2012). The Paleo Diet: Fact or Fiction?
Cano, P., Jiménez-Ortega, V., Larrad, Á., Toso, C. F. R., Cardinali, D. P., & Esquifino, A. I. (2008). Effect of a high-fat diet on 24-h pattern of circulating levels of prolactin, luteinizing hormone, testosterone, corticosterone, thyroid-stimulating hormone and glucose, and pineal melatonin content, in rats. Endocrine, 33(2), 118-125.
Conlee, R. K., Hammer, R. L., Winder, W. W., Bracken, M. L., Nelson, A. G., & Barnett, D. W. (1990). Glycogen repletion and exercise endurance in rats adapted to a high fat diet. Metabolism, 39(3), 289-294.
Eaton, S. B., & Eaton Iii, S. B. (2000). Paleolithic vs. modern diets–slected pathophysiological implications. European journal of nutrition, 39(2), 67-70.
Goedecke, J. H., Christie, C., Wilson, G., Dennis, S. C., Noakes, T. D., Hopkins, W. G., & Lambert, E. V. (1999). Metabolic adaptations to a high-fat diet in endurance cyclists. Metabolism, 48(12), 1509-1517.
Gropper, S., & Smith, J. (2012). Advanced nutrition and human metabolism: Cengage Learning.
Hockett, B. (2012). The consequences of Middle Paleolithic diets on pregnant Neanderthal women. Quaternary International, 264, 78-82.
Horowitz, J. F., & Klein, S. (2000). Lipid metabolism during endurance exercise. The American journal of clinical nutrition, 72(2), 558s-563s.
Horvath, P. J., Eagen, C. K., Fisher, N. M., Leddy, J. J., & Pendergast, D. R. (2000). The effects of varying dietary fat on performance and metabolism in trained male and female runners. Journal of the American College of Nutrition, 19(1), 52-60.
Ikemoto, S., Takahashi, M., Tsunoda, N., Maruyama, K., Itakura, H., & Ezaki, O. (1996). High-fat diet-induced hyperglycemia and obesity in mice: differential effects of dietary oils. Metabolism, 45(12), 1539-1546.
Jeukendrup, A. E. (2003). High-carbohydrate versus high-fat diets in endurance sports. SCHWEIZERISCHE ZEITSCHRIFT FUR SPORTMEDIZIN UND SPORTTRAUMATOLOGIE, 51(1), 17-24.
Jeukendrup, A. E., Saris, W., Schrauwen, P., Brouns, F., & Wagenmakers, A. J. (1995). Metabolic availability of medium-chain triglycerides coingested with carbohydrates during prolonged exercise. J Appl Physiol (1985), 79(3), 756-762.
Johns, T., Nagarajan, M., Parkipuny, M. L., & Jones, P. J. (2000). Maasai Gummivory: Implications for Paleolithic Diets and Contemporary Health1. Current anthropology, 41(3), 454-459.
Lambert, E. V., Speechly, D. P., Dennis, S. C., & Noakes, T. D. (1994). Enhanced endurance in trained cyclists during moderate intensity exercise following 2 weeks adaptation to a high fat diet. European Journal of Applied Physiology and Occupational Physiology, 69(4), 287-293.
Marten, B., Pfeuffer, M., & Schrezenmeir, J. (2006). Medium-chain triglycerides. International Dairy Journal, 16(11), 1374-1382.
Mašek, J., & Fabry, P. (1959). High-fat diet and the development of obesity in albino rats. Experientia, 15(11), 444-445.
Miller, W. C., Bryce, G., & Conlee, R. (1983). Adaptations to a high fat diet which increase exercise endurance in male rats. Am Physiological Soc.
Nestle, M. (2000). Paleolithic diets: a sceptical view. Nutrition Bulletin, 25(1), 43-47.
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Oakes, N. D., Cooney, G. J., Camilleri, S., Chisholm, D. J., & Kraegen, E. W. (1997). Mechanisms of liver and muscle insulin resistance induced by chronic high-fat feeding. Diabetes, 46(11), 1768-1774.
- rtenblad, N., Nielsen, J., Saltin, B., & Holmberg, H. C. (2011). Role of glycogen availability in sarcoplasmic reticulum Ca2+ kinetics in human skeletal muscle. The Journal of Physiology, 589(3), 711-725.
Outram, J. (2014). Paleo for Beginners: All about the Paleo Diet: How to Get Healthy & Lose Weight: Speedy Publishing LLC.
Rowlands, D. S., & Hopkins, W. G. (2002). Effects of high-fat and high-carbohydrate diets on metabolism and performance in cycling. Metabolism, 51(6), 678-690.
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Smith, R. (2012). Paleo Diet Guidelines & Procedures: Caveman Diet: ShirdInc.
Todoric, J., Löffler, M., Huber, J., Bilban, M., Reimers, M., Kadl, A., . . . Stulnig, T. (2006). Adipose tissue inflammation induced by high-fat diet in obese diabetic mice is prevented by n− 3 polyunsaturated fatty acids. Diabetologia, 49(9), 2109-2119.
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Volek, J. S., Love, D. M., Avery, N. G., Sharman, M., & Kraemer, W. J. (2001). Effects of a high-fat diet on postabsorptive and postprandial testosterone responses to a fat-rich meal. Metabolism, 50(11), 1351-1355.
Toeing the line of long race is one of those unique experiences that not many people ever get to enjoy. The event may have started the day prior with a pre-race dinner and a race brief. This is usually the first time you get to check out the competition. People lounging around with impressive belt buckles and shirts sporting the name of their craziest race like “Badwater” or “Leadville”. In another sport this might be an attempt to intimidate the competition, but often I find myself doing this just to feel like I belong. As if to say, “Yes, I’m one of you.” The morning of, I chat it up with people I met the night before and we spend some time sharing brief war stories from other races. Before the start of a long race, there’s always a bit of nerves. Countless pee breaks between conversation with the inevitable race looming ahead. The uncertainty of whether you’ll get injured or start throwing up, or end up dropping out for any number of reasons. For me, I try to shut it out and focus on the things I can immediately control. Getting coffee, relieving the bladder. If I think too much about the shear enormity of it, I’ll be overwhelmed. This is a feeling which pervades most of the race.
Finally, after a bit a waiting, the race will begin. Usually, the front of the pack shoots out and I’m tempted to keep pace with them. This lead pack is usually a mix of very experienced, fast runners, and people that get caught up in the excitement. I must admit it is very tempting to burst out of the gates and run with abandon during the first quarter of the race, but I’ve done that, and ended up barely able to walk by mile 40. To avoid the over-zealousness of the start, I pick someone that will run a conservative pace the first leg and try to stay with them.
So what am I thinking about? I’m thinking about anything but what I’m trying to do. I talk to people, look at the scenery, watch my feet, pray. Anything to not focus on how many miles I have left to run. I used to have this annoying habit of calculating my pace and predicted finish time at every aide station. It still pops into my head as I pass certain mile markers in a race. I discovered pretty early on this can lead to disaster. Everything seems encouraging until mile ~60 when you try to figure out the math and your fatigued/sleep deprived mind come up with an absurd figure, “Oh, I need to average a 6 minute pace for the next 40 miles to finish.” The math never works out the second half of the race. So instead I try to distract myself. Distract myself from the soreness, chaffing, the mad calculations, the fact that I still have over a marathon to run and I’m exhausted.
The entire adventure seems impossible until about the 75 mile mark. That’s the first point that I actually feel like I might be able to finish the race. At this point the mind is swimming between optimistic, “That beer is going to be delicious at the finish.” and despair “I can barely even walk this stretch. I’m never going to finish. I’m a terrible husband and father for being out here.” I try to keep moving forward.
Eventually I get to within 10 miles of the finish. At this point I am either an emotional basket case with tears and despair, or I am furious. I prefer the rage. I begin thinking of all the things that piss me off from the absurdly rocky section 20 miles ago, to the dish soap flavored hammer products at the aide stations. The madder I get, the better, because that anger overrides the pain and I can sometimes even run the last 10 miles.
It’s difficult to really put into words just how you feel at the finish line. Relief from not having to run anymore, exhausted, ecstatic. I think every emotion I’ve experienced in life comes in waves, and they pass over and around me until I drift to sleep. It won’t really set in for a few days just what I managed to accomplish, but for now, it’s enough to be done.
If you have read my previous posts, you may have noticed that I talk about the differences between things which will help you finish a race at a faster pace vs things which will halt your race. While there is likely some overlap in these variables, my reading of the research leads me to conclude that nutrition, psychology and injury play a larger role in whether you can finish a 100 mile race, while fitness largely determines how fast you finish.
When I was in my undergrad, I had the privilege of competing in collegiate fencing. I was terrible at it, but the experience exposed me to psychological techniques that people use to improve their performance. I have found that these techniques are important tools to finish a 100 mile race. The techniques I mainly use are imagery, and positive self talk. I will briefly explain how to use these to avoid dropping from a race early.
Imagery lets us establish a belief in our minds by using our imaginations. One of the most difficult things for a novice in ultrarunning to do is getting to the point that you believe you can actually do this. If you lack this belief, you will most likely drop from a race when you start feeling pain or tiredness because finishing will seem impossible. In the weeks prior to the race, spend some time imagining yourself in several situations. First, maybe watch some videos of people running and finishing 100 mile races and imagine yourself as that person crossing the finish line. Second, imagine yourself at the height of fatigue ~60-70 miles into the race and imagine yourself continuing to race through this feeling. You want to train yourself mentally to push through the worst periods of a race. I say mile 60-70 because that seems to be the point where you are exhausted and you still have a significant distance to run. It’s usually the make or break point for me in a 100 miler.
The second technique I often use is positive self talk. Throughout a 100 mile race you will be tempted to have despairing or negative thoughts. “I feel terrible, I am tired, I don’t want to even do this” We’ve all had these thoughts. The problem is, as the race progresses, if you allow these thoughts to progress they will turn from “I am tired” to “I can’t do this” and you will quit. How I use positive self talk is to replace the negative thoughts with a positive thought. When I feel tired, instead of allowing myself to think about and dwell on the fatigue, I say out loud “I feel great” or “I feel amazing”. Replace the negative with a positive phrase. Keep this up throughout the race and you can stave off the decline in psychological state.
The last thing you might want to do is incorporate music. Download some positive music. Research shows that you get the most effect from music you enjoy and that is not overly familiar. Break down and buy a couple new albums for your mp3 device the weeks before the race. I also find that I get a stronger effect if I spend a couple weeks before the race not listening to any music.
If this post interests you, consider some of the following books to add to your collection.
Just about every time I tell someone that I run 100 mile races I get reactions that starts with shock and surprise, followed by the universal question “why would someone want to do that?” It’s a question we all struggle to answer in words because the it’s so glaring obvious to us. I find myself stammering out a few incoherent sentences about enjoyment or some other aspect, but to me, I find it more incomprehensible as why you wouldn’t want to run 100 miles. The idea of not wanting to do this is as foreign to me as the thought of wanting to spend a Saturday in bed or enjoying a lifetime docudrama on a dad’s misadventures at the grocery store. To me, what I do is the natural expression of who I am. I want to spend all day in nature, hanging out with these incredible people, drinking good beer, and yes running. So in some sense running a 100 mile race is no different than any other activity that people enjoy. However, I feel there are some things we can pull out that attract us to this idea.
First and foremost, there is something about the distance which captivates my imagination. 100 miles! It sounds impossible. The distance is extreme enough that the first time we hear about it, we cannot fathom it. It’s the unknown. It’s like someone 300 years ago hearing about this exotic land across the sea and wanting to experience it firsthand. With so few real frontiers available, the modern explorer may turn inward and desire to explore their own limits. How will I feel at 60 or 70 miles? What about the finish line? What is it like to have this experience?
Second, I think most people running these races are in search of something unique. I suspect a lot of my ultrarunning friends may be like me in that we search out the strange and unique things. I cannot be interested in “normal” things. My wife says that I have to find the strangest thing to be obsessed with. Due to the strenuous nature of running 100 miles, it is still fortunately considered strange. I hope we never lose that.
Third, the ultrarunning community provides us with a tribe. We all have similar experiences that most people cannot relate to. Through this shared experience we have a group to identify with. I think it may be a reaction against modern culture which tends to promote sameness. We watch the same tv programs, go to the same schools with the same curriculum, so that we can all be part of one giant group called “americans.” But, it’s all cold and impersonal. We may not really feel that we fit into the national culture, so we retreat to our mountain trails to be with people we share a deeper connection to. People we have bled with or shed tears with, of joy and pain.
Lastly, I think running 100 miles allows us to have an emotional journey. We get to experience the full spectrum of human emotions in one day. It is a spiritual and emotional quest of personal understanding. One I hope you as my reader get to one day experience for yourself.
If you are new to the sport of ultrarunning, you will at some point be assaulted by the variety of hydration options out there. Regardless of the plethora of choices, there are some basic categories, and these categories tend to encompass a common set of positive and negative features. First, we could break things down by bottles vs bladders. Bottles have the advantage of being easily trackable throughout a race because you can visually see how much you’re drinking. They are also cheap and easy to clean. Many companies have tried to develop their own “ideal” bottle, but I find my favorite bottle is the Gatorade Sports bottle with the twist top. It’s large enough that I usually need only one, and I can wrap my headlamp around it. Also, due to the disposable nature I can just recycle it after the race instead of finding it months later stashed in a bag of gear covered in mildew.
The obvious advantage of a bladder is the convenience of being able to sip through a straw. This is also a disadvantage though since you may tend to over or under consume fluids this way. I like to be anal about tracking my fluid consumption and matching sodium intake. You can buy an inline meter for a bladder to tell you how much fluid you have consumed, like the one below.
However, there are numerous other reasons I personally dislike bladders. First would be the price. These are just some samples of replacement bladders, which generally cost ~20 dollars.
For that same price I could get 10 bottles and have my imaginary crew keep a stock of filled bottles. Another major disadvantage is the durability. When I used bladders, I generally had to buy a new bladder every month due to either mold or tears that would develop around the closure, or on the bladder itself. If you are a poor PhD student like me, this becomes unsustainable. I would say though that certain races may provide few opportunities to refill your fluid and a bladder does allow you to carry more fluid usually.
The other way we could break things down by is belts, packs/vests or handhelds. A lot of people love handhelds, but personally, I really don’t want to have anything heavy in my hand because it would fatigue my shoulder muscles. This is especially important for my as I have shoulder problems. That said, some people swear by them and love the shock absorption from falling on the bottle instead of their hands. I personally use belts, but they also have a drawback in that they either flop around or you cinch them so tight they press on your GI tract which can be uncomfortable. I own several running belts and I can tell you the double bottle belts are terrible unless you just need a lot of fluid. The double bottle belts become uneven after a couple sips and flop badly. Not to mention the extra weight is uncomfortable on the GI tract. I should also say, if you’re running 50 or 100 miles, you probably need some storage space on whichever option you choose. For this reason I use nathan single bottle belt with storage shown below.
Despite all the drawbacks of belts, I still prefer them for two reasons: they are cheap, and they absorb less heat than the vests. I’ve used vests, and they are convenient, but since I prefer hot races, I don’t want something sitting against my back holding in heat. Also, nearly all the options have a bladder. Despite this, if I were to run a long race without support I would prefer a vest since they usually have the most storage space. Although I might ditch the bladder or use it to refill bottles. And if I had the money this is the vest I would buy.
I hope this helps you in your endeavor to find the right hydration system for you.
We recently published a study titled “Physiological Parameters Associated with 24 Hour Run Performance.” The paper is open access if anyone wants to read it. Just type the title into scholar.googel.com. One of the interesting things we observed in the data is that average running speed was highly correlated with fitness, but total mileage completed during the race was not. Taken in context with studies done by Guillaume Y Millet, it seems that if all other variables are held equal, the person that has the most cardio respiratory fitness will likely have the best performance in a race. Unfortunately, this is rarely the case except in a laboratory setting. In an actual race, several variables seem to act to limit or halt performance early. These variables likely include: Nutrition, susceptibility to injury, and psychological arousal. If for instance, you fail to take in enough salt, you could develop hyponatremia (too little sodium in your blood), which could end your race early. Or, if your leg joints were more unstable, you could develop a race ending injury. The thing which is interesting to me is about our study is the possibility that given enough data, we could predict an optimum race pace. I will attempt in the near future to publish our regression equation for anyone interested. It should be noted that this was developed for a hot, summer race, and the ideal pace may differ depending on environmental conditions. The idea of this is somewhat supported in the literature by the works of Martin D. Hoffman who has previously shown that minimizing changes in pace throughout a race is a strategy often associated with winning.
Now that we’ve covered the basics of fatigue during an ultramarathon, what do we do to reduce or minimize it? One of the key points I hope you picked up on is that a large portion of fatigue during an ultramarathon occurs because the brain reduces the amount of signal it sends to activate the working muscle. Therefore, the first thing I would focus on to reduce or minimize fatigue is to somehow boost that signal from the brain. How do we do this? Well, there’s several things we can do to boost the signal from the brain to activate more muscle: listening to music, having a pacer, sparing use of anti inflammatory drugs, and possibly alcohol consumption. All of these methods to some degree distract the brain from the perception of pain. When the brain senses pain from the working muscles, it may reduce running pace in an attempt to reduce the pain. Generally, anything which reduces boredom would also have a similar effect. The other effect we would want is to minimize inflammation. Diet and stress prior to the race would likely affect inflammation. If you are stressed out or eating poorly then you’ll have more inflammation going into the race. Conversely, if you maintain a high fiber intake with plenty of probiotics (yogurts) and you minimize life stress prior to the race then you would likely start with reduced inflammation. During the race, you can minimize inflammation by avoiding surges in your pace. However, eventually (6-8 hrs) your working muscles will produce inflammatory signals which can feedback to the brain and reduce the pace. A well timed dose of ibuprofen or 1 alcoholic beverage may reduce inflammation and restore pace for a few hours. The trick is want to time it right to avoid boosting your pace early on resulting in more inflammation. What I generally do is attempt to run the first 30-50 miles of a 100 mile race without anything to help me. No music, pacers, or pills. I immerse myself in the experience and focus on getting plenty of food and drinking appropriate amounts of fluid. Once I get past this initial phase, I switch on the music in 5-10 mile segments. I rarely have pacers, so this would likely alter my music use. I usually hold off on any anti-inflammatory drugs till at least the 100k mark. I wait later if I can still run. I take a very low dose ibuprofen. I would recommend consulting a physician before using any anti-inflammatory drugs since using these when dehydrated can result in kidney failure. The anti-inflammatory drugs will make me feel amazing for 10-15 mile bursts. I may end up taking a total of 2 doses. I should note that many people drink beer for the same purpose which can both suppress inflammation and provide a potent dose of energy. If you can make it within 5-10 miles of the finish line, the excitement of finishing will take over.
Before we can really discuss fatigue, we first need to have a basic definition to work from. Fatigue is generally defined as a temporary decline in the ability to produce force with the skeletal muscles. This can occur from either a disruption of the working muscles, or a decline in the ability to activate that muscle. Some of you may be wondering why I’m talking about force generation in an ultrarunning blog. It’s simple, the speed you are able to while running is dependent on your ability to generate force. In running, we see fatigue in a decline in running speed.
the reasons for fatigue vary depending on the length and type of activity. In a 5k, fatigue is usually the result of temporarily altering the environment within the muscle cell. When speed increases, higher threshold muscles (muscles which are more difficult to activate) get used which due to their untrained state will produce fatiguing byproducts. These byproducts then make it more difficult to activate the muscle and reduce force production / running speed. This could occur at any race distance if the runner did not pace themselves appropriately. During an ultramarathon, you might experience this running up a steep hill. Generally speaking, this form of fatigue is short in duration and may or may not impact your performance long term in say a 100 mile race. The disruption to the muscle cell can easily be corrected, if the pace is reduced. After running a steep uphill section, you may feel tired for a few minutes and bounce back.
Another cause of fatigue is depletion of carbohydrates stores, also known as glycogen depletion. This occurs when carbohydrate usage exceeds intake over a sufficient time period to use up the stored carbohydrate. Numerous strategies have been used to avoid glycogen depletion. The most common strategy is to carbohydrate load. The recommended way to carbohydrate load is to taper mileage 2-3 weeks prior to the race, and slightly increase carbohydrate intake. This has been shown to significantly increase carbohydrate stores. While this may extend the time to carbohydrate depletion, it will likely not be sufficient in and of itself to eliminate this aspect of fatigue from 100 mile run. In order to eliminate carbohydrate depletion as a cause of fatigue you need to focus on one of two strategies. Either increase the amount of carbohydrate you can consume during the race, or decrease the amount of carbohydrate used during the race. The first strategy means training your GI tract to tolerate large volumes of fluid carbohydrate during exercise. I generally recommend training with your planned nutrition the 2-4 weeks prior to your race. It may only take ~10 days to adjust, but it’s also beneficial to train yourself to eat to your plan. The second strategy, reducing carbohydrate usage is the subject of much debate these days. First, increasing your fitness will lower carbohydrate use by boosting fat use at submaximal paces. The second way is to go on a high fat low carb diet. The fuel you use during exercise is sensitive to the food you eat. Increasing fat intake and decreasing carb intake will make your body burn more fat. However, there is little evidence suggesting this actually improves race performance, and no evidence as to the long term health consequences of ingesting ~70% of your calories from fat. Some researchers decry high carb diets as leading to accumulation of arterial plaque, but at least there are several intermediate steps to forming plaque with a sugar. That’s enough to give me pause over whether I want a high fat approach. It should however be noted that some notable ultrarunners swear by high fat diets, notably Zach Bitter the 12 hour world record holder.
The last form of fatigue I would like to mention is somewhat speculative. We know from studies of people with chronic fatigue that the immune system can decrease the ability of the brain to activate muscle through inflammatory signalling molecules. I discussed this in my previous post on overtraining. Research has shown that during the course of an ultramarathon, the working muscles and immune cells produce significant amounts of the signalling molecules. The Millet lab has also shown that voluntary muscle activation decreases throughout a 24 hour race. While speculative, it is possible that some of the decline in pace seen throughout a 100 mile race could be due to increases in inflammatory signals. How could we combat this form of fatigue? One way would be to take an anti-inflammatory medicine such as ibuprofen or Tylenol (NSAIDs). These medications interfere with production of the inflammatory signals. The research over NSAIDs has clearly shown that a using these drugs early in the race or before to stave off inflammation is a bad idea. Probably what happens is they promote faster paces in the early part of the race which later results in more inflammation. What has not been tested is whether a low dose NSAID may be beneficial later in the race after pace has already declined. It should be noted that taking an NSAID late in the race could have dire consequences if the person were dehydrated or had reduced kidney function. Please use caution since people have gone to the hospital with kindey failure from taking NSAIDs late in the race. You should probably consult your doctor if you plan on doing this. Another option would be to use low dose alcohol or a nutritional supplement such as tumeric or resveratrol.
The last thing I’ll discuss is not actually fatigue, but muscle injury. While muscle injury is classically not thought to affect a single bout performance, the length of time of an ultramarathon is sufficient to allow inflammation from the injury and reduce the ability to activate the muscle. If your race includes a lot of elevation gain and loss, then consider adding downhill running bouts to your training as this can over time reduce the severity of the injury.
If you’ve picked up any running related literature in the last few years then you’ve probably heard of over training. What is over training? To be entirely honest, there is no clear definition of overtraining. Most sources agree that overtraining is a general fatigue brought on by training too intensely or too long without proper recovery. In other words, you feel like crap when you train too much. The problem with this general definition is that it doesn’t really explain the mechanism. Yes, increasing training volume and intensity add to the stress on the body, but when you get down to it, but the situation is more complex than that. Some signal in the body must relay this information to the brain. While it is still unclear how this works, some recent research with people suffering from chronic fatigue may hold the answer. To fully understand this you need to know something about how the immune system works. Most cells in the body, including muscle cells, produce signaling molecules. When muscle cells contract they will eventually produce a class of these molecules known as the interluekens, which are the cause of inflammation. If sufficient levels of these of these molecules get produced, they can feedback to the brain and decrease the motor drive in the brain. This results in the reduced pace often seen in over training.
So the question is, what can we do to correct this or delay it? The first thing is that over time, the muscles will likely become accustomed to the increased work load and produce less inflammatory markers. That may not help though in the short term. For the athlete looking to squeeze just a little more training out, I would recommend limiting other sources of inflammation. One of the largest sources of inflammation is the GI tract since it more directly interacts with environmental stressors from food. One of the easiest ways to reduce GI inflammation is increasing fiber consumption. Many of the bacteria vital to proper GI function feed on fiber, and increasing the good bacterial populations may reduce systemic inflammation. I think this may be why Scott Jurek had such a great effect when switching to vegetarian diet. Not only did he get a high dose of vitamins and minerals, but he probably optimized his GI bacterial populations. The second major thing is to supplement with live bacteria, or pro-biotics. I prefer kefir, but numerous forms of yogurts have healthy bacteria.
While somewhat speculative, moderate alcohol consumption (1 drink/day women; 2 drinks/day men) has also been shown to reduce inflammation. I suggest that maybe drinking moderately may reduce chances of overtraining, but this has not been tested in the literature.