A research published by the official Journal of the American College of Sports Medicine has shown that training deliberately with a low availability of glycogen can increase the metabolic load.
This strategy is called “sleep low”, which means that after performing a high intensity training session in the late afternoon/evening, an athlete must not replenish the glycogen store with carbohydrates and have a meal with low/zero carbs, then sleep and finally do an endurance session in the morning in a fasted state.
You can find the PDF of the study here:
What we must point out from this research is this:
Therefore, a block of training accompanied by the “sleep low” strategy must be periodised in order to obtain the metabolic adaptation. Professor John Hawley suggests a block of training of 3 weeks with 1 “sleep low” sessions per week followed by a gap of 2 weeks. However, “sleep low” should be done in the early aerobic building phase of a training plan to avoid alack of energy in the weeks leading to a race.
What does it mean for beginners, amateurs and experienced athletes?
It simply means that every stimulus that increases the metabolic load makes the body adapt to it. “Sleep Low”strategy improves the ability to use fat reserves as an energy source.
If it is done correctly, in a periodised block of training with specific rest days, it can teach your body to keep going when is low on glycogen during the last part of a race, it can help you to keep going to the next water/nutrition station in a race in case you drop your nutrition along the course and so on…If it is done unproperly, this nutrition strategy can lead to fatigue and a loss of fitness.
What is the take home message from this study?
The most important thing for an athlete is a well balanced and varied diet, full of nutrients and minerals and vitamins. Carbohydrates should be the main fuel for athletes and nutrition could be periodised to achieve specific performances without cutting out any macros. However, nutrition must be bespoke for every individual, as every person reacts and metabolises nutrients in a different way; the same concept applies for glycogen stores which varies depending on the size of the athlete.
A balanced and nutritious typical day to do “sleep low” once week for 3weeks in the early endurance building block could be this:
2 eggs, half avocado, spinach and toasted sourdough
high protein yogurt with berries, honey, linseeds, cashews, dark chocolate
salad with lettuce, tuna, steamed spelt, hummus, extra virgin olive oil.
NO AFTERNOON SNACKS PRE WORKOUT
HIGH INTENSITY TRAINING SESSION
LOW CARB DINNER:
grilled chicken breasts with grilled courgettes, tomatoes and aubergines
SLEEP LOW (on carbs)
WAKE UP AND DO ENDURANCE ON AN EMPTY STOMACH
BREAKFAST TO REFUEL:
Porridge with 1 banana, peanut butter and honey