Train low race high: an intro to alternative fueling approaches
In endurance training there is an advanced concept called “Train low race high”. The concept centers around increased efficiency burning endogenous (inside of you) fuel sources. The theory is that an athlete needs to be good at burning fat for fuel, but at the same time not lose their ability to metabolize glucose for fuel. The benefit to using fat as a fuel for exercise is that you essentially will never run out of energy if you keep your pace slow enough. For competitions that last more that 3 hours, burning fat is favorable to sugar because glycogen runs out in about 3 hours at high intensities. The problem is that if you only work in a glycogen depleted state, you will decrease your ability to oxidize carbohydrate. This balancing act is called respiratory quotient or RQ. This varies both depending on the individual metabolism of the athlete and the metabolic demand of the event. Likewise, if you only train in a highly carb fed state you will not be as efficient at using fat. This may lead to bonking. The drawback to training low too much is it effectively puts the breaks on your speed and heart rate via a concept is called “glycogen sparing.” This can be advantageous in a very long race because you will have more left in the tank to get you through the entire race. However, it may decrease your high end performance and cause you to run slower. With these ideas in mind sports nutritionist have developed cyclic carb intake and training plans to help to maximize efficiency for both fuel types. Read more to dig in a little deeper on these concepts.
Literature on Train low race high
Several studies examined the effects of a ketogenic diet on substrate utilization during submaximal exercise. They found one of main adaptations is Fatty acid oxidation is up-regulated and carbohydrate utilization from glycogen is shunted. In Jeff Volek’s landmark study on the effects of a ketogenenic diet on exercise performance and substrate utilization, he compared people to themselves before and after adapting to a ketogenic diet. Pre intervention subjects burned more glycogen at the same intensity than post intervention subjects. In the absence of a fuel source your body will adapt and use an alternative fuel. In this case body fat or free fatty acids. What is interesting is that performance was virtually unchanged in the trials. In other words, the subjects shifted around what they were burning, but that did not impact performance capacity. This is likely because of glycogen sparing. You need sugar to go fast. Current research is conclusive on this. It’s basic metabolism. The the “train low” leg of the “train low race high” came from the concepts in Volek’s work.
Check out some short term glycogen sparing results:
How do you attain the benefits of training in a ketogenic state, while maintaining the ability to quickly shift into a glycolitic state? That is where “train low race high” concept comes into play. A unique study in the American Journal of Physiology found that some of the same adaptations found long term in a ketogenic diet can be achieved acutely by training in a “glyco-depleted” state. The way it works is to conduct high intensity workout in a glycogen depleted state. They did running trial of six sets of a 3 minutes to 3 minutes work to rest ration. The work load was 90 percent heart rate max and the rest period was 50 percent HRM. The night before this workout, subjects complete a specific protocol to ensure glycogen stores would be depleted and did not re-feed carbohydrate. This study actually sought out to examine how this would effect P53 tumor suppressor gene expression and how this would effect AMPK regulated mitochondrial biogenesis, but the concepts they explored here can be applied to performance. Turns out P53 expression increased 3 fold in response to training in “glyco-depleted” state and not re-feeding carbohydrate post workout. This has implications which go beyond the scope of this article. Namely you can influence gene expression in favor of increased mitochondria biogenesis by training in a fasted state.
Following the glycogen depleting workout you do not re-feed carbohydrate. Your training will deviate slightly from the protocol in the study. Day 1 conduct a high intensity workout similar to the day 2 protocol. The next morning conduct a steady state 70 percent HR max 40-60 minute workout. This will force your body to up-regulate FA oxidation rates because of the acute glycogen sparing response to low glycogen levels. Over time by training in this fashion you will improve your ability to burn fat to meet the demands of a workout. After the morning session you can refuel carbohydrate or wait until the weekend. By completing one workout in a high carb state and the next in a low carb state you improve FA oxidation rates while staying efficient at utilizing carbohydrate for fuel. Theoretically, this is one way to avoid some of the high end performance losses that often accompany a ketogenic diet. This study examines some of the draw backs of a high fat diet on performance. There were some design flaws in this study because the subjects only ate high fat for 6 days before a carb refeed and they only at 68 percent calories from fat. 80 percent is required for ketosis to allow true fat adaptation to occur. It also generally takes more that 6 days. They noted some performance decrease on sprint cycling trials, presumably because of an impaired access to intramuscular glycogen stores.
By following the strategy outlined in this article you may not lose performance at high intensities. The first workout is in a high carb state so you do wont lose the ability to burn sugar. The second workout improves your efficiency to mobilize fat for fuel. This is perfectly applied to something like Spartan Races, adventure runs or long races that include climbing. Long term adaptations to this type of training have yet to be studied, but the preliminary findings are quite interesting. Keep in mind that performance will likely suffer during this protocol. The cellular adaptation will be greater in the long run. Isn’t that why you are training in the first place?
In the days leading up to a race, you will want to enter it in a high carb state. Here’s a brief abstract on re-fueling strategies. This way you will have maximal glycogen stores. Many studies suggests that immediately pre-race it is not ideal to fuel up on carbohydrate or protein. It’s important to keep insulin levels low to allow your body can become catabolic. In a catabolic state you will easily release it’s endogenous fuel. About 30 minutes into the race ingest about 20 grams CHO. Try it out and let me know how it goes in the comments below. Or ask me any questions you have on the article.
Elijah Markstrom 