For athletes, especially endurance athletes, the nutrition dogma has always been to consume significant amounts of carbohydrates post-exercise in order to maximize recovery and promote the best training adaptations. It’s well accepted in the research that muscle glycogen – the carbohydrate stores on your muscles – is replenished much more readily in the first few hours after training. Higher carbohydrate (and protein) meals help to rebuild glycogen and to offset the training-induced increase in cortisol stress hormones.1,2
But what would happen if you didn’t eat after exercise? Would it completely derail your recovery and future performance? Many believe so. But surprising new research is starting to show that bucking the sports nutrition dogma and strategically avoiding replenishing your glycogen from time-to-time may actually improve your performance
What is the Sleep Low Strategy?
The sleep low strategy, a new concept in endurance sports, involves training intensely in the evening (after a typical meal) and then actively avoiding carbohydrates in the post-workout meal (some protein and fats are allowed) before settling down to sleep.
The “sleep low” nickname refers to maintaining low glycogen stores as you head off to bed, before engaging in another low intensity exercise session in the morning before breakfast.
The notion of not adequately replenishing glycogen post-training is thought to be an absolute performance and recovery killer, but a recent study in France of triathletes highlighted the potential benefits of this sleep low strategy.
Twenty-one triathletes were divided into a sleep low group and a control group. They consumed the exact same total daily carbohydrates over the 3-weeks, but at different times throughout the day. The control group consumed their carbohydrates across the day (i.e. breakfast, lunch and dinner) while the sleep low group consumed all of their carbs at breakfast and lunch, but nothing after their evening training, or before their morning session.
The researchers found after 3 weeks of doing the exact same training protocol, the sleep low group improved significantly more than the control in their submaximal cycling economy, supra-maximal cycling time to exhaustion and 10-km running time. Not to mention a significant decrease in fat mass.3
Don’t Cut the Carbohydrates Just Yet
Between the benefits of sleeping in a glycogen depleted state and so much being written about how high-fat diets can improve the fat-burning machinery in endurance athletes should we be restricting carbohydrates all the time to improve our performance?
While this may be true for some, like most things in a life, there is catch. If you want to lose weight and exercise at 65% of your maximum effort, then a low-carb, high-fat diet is a pretty good approach. However, if making the podium, winning a gold medal, or achieving a personal best is your goal then relying on fat for fuel is not going to cut it.
At high exercise intensities – like what you’d experience in a race – your body runs on about 90% carbohydrate. That’s right, when it’s time to hit the accelerator and pass your competition it won’t be the fats powering you, it will be the carbs. In fact, high-fat diets actually impair the muscles’ ability to breakdown glycogen, thereby limiting your access to the high-octane fuel.4
Individualize Your Plan To Supercharge Performance
Fortunately, it may be possible to get the best of both worlds, if your goal is performance. Use periodic three to four day blocks to “sleep low” and subsequently “train low” the following morning (i.e. low glycogen) to improve your fat-burning potential and ability to finish off a race.
But then avoid this approach when you get closer to competition and performance becomes critical. The research is still very clear that come race day, adding the carbs back in will allow you to perform better.
However, if your goal is to lose weight, boost your energy, and improve your health than the sleep low strategy could be very beneficial. I regularly see very active and experienced cyclists who ride hundreds of miles per week and are still 20-30 lb. overweight because of their very high-carbohydrate fueling.
Further, this focus on fueling enough before, during and after exercise can lead to an excess of simple carbohydrates in the system and subsequently increases in triglycerides and smaller, denser LDL particles which all increase cardiovascular disease risk.5
A sleep low and train low strategy could be a game-changer for these athletes. Not only would it improve cycling performance, but it would also significantly reduce body-fat stores and improve health.
In truth, athletes have been tinkering with sleep low and train low strategies for decades, however now scientists are starting to get an understanding of how these strategies work and who they can potentially impact most. Think of “sleep low” and “train low” as just another few tools in your tool belt of training strategies. Plan and periodize their use to maximize their benefits and limit their potential shortcomings.
Dr. Marc Bubbs ND, CISSN, CSCS