Nutrition: The Road To More Efficient Climbing (Part 1)
Robert Portman is a researcher in the broader field of sports science, who has worked with athletes in almost every sport, has written three books on nutrition and sport, and even developed one of the first post-exercise recovery drinks.
After his first experience in climbing, which was motivated by his young daughter, he decided to conduct the first research on the effect of nutrition on the performance of our body and organism during climbing, as there was no such research until then.
The research was conducted in collaboration with Professor John Seifert of Montana State University, whose laboratory is equipped with a climbing wall. Eight men and one woman participated in the survey with an average of 9 years of climbing experience. The results of the study were presented in 2011 at the annual university sports pharmacy meeting.
Physiology of climbing
From the point of view of physiology, climbing is unique. In most activities an increase in exercise intensity parallels an increase in oxygen consumption. However, at least with high-level climbers, oxygen consumption does not necessarily increase with climbing difficulty. Furthermore, the total energy expenditure is much less than in cycling or running because it is limited to a selective group of muscles which is mainly due to prolonged and intermittent contraction of the forearm.
Anaerobic metabolism plays a key role in energy production for muscle contraction in climbing. Muscles have two energy systems: an aerobic one, which produces energy in the presence of oxygen, and an anaerobic one, which produces energy in the absence of oxygen. Sustained contraction of the forearm relies almost exclusively on the anaerobic system, which is only about five percent as efficient as aerobic. This reliance on the anaerobic system has important consequences: Muscles fatigue more quickly and the stored nutrients in our bodies are depleted more quickly than in aerobic exercise.
A third consequence of anaerobic metabolism is the accumulation of acid in the muscles. During climbing, acid levels can increase to tripling levels (compared to resting levels) and remain elevated even after the climb. Acid accumulation is largely associated with muscle fatigue. For example, handgrip strength can decrease by 57 percent from the beginning to the end of the climb. Muscle fatigue is not the only issue for climbers. Brain fatigue, also known as central fatigue, is a major factor in performance decline. Fatigue in the signals coming from the brain can directly affect the strength of muscle contraction. In addition, brain fatigue can result in loss of concentration.
Although nutrition can mitigate muscle exhaustion, store energy and delay the onset of fatigue, climbing imposes practical limitations on refuelling methods. Because weight and bulk are the enemies of climbing, the food you carry should be lightweight and easily stored on you. The climbing environment also imposes additional restrictions. Heat, humidity or winds are conditions that can accelerate fluid loss and lead to dehydration. In light of these physiological and practical obstacles, how can a climber choose the best combination of nutrients to achieve optimal performance during a climb and have rapid post-climb recovery?
The ideal way to develop an effective climbing nutrition plan is to segment the climbing effort into three stages, recognizing that each stage has different nutritional needs:
– Start – Maintenance – Recovery
Most climbers use the start or pre-climb stage to fully hydrate their bodies. Their beverage of choice is water, and typical recommendations suggest drinking a liter or more before starting the climb. However, fluid intake should be guided by three factors: the number of climbs (or pitches) one expects to make in a given time frame, temperature, humidity, and the fact that, on average, our bodies can only absorb about 36 ounces of fluid per hour. If you are fully hydrated before you start your climb, supplement by drinking 16-20 ounces. Drinking too much fluid before you start climbing will cause you discomfort and if you exceed your body’s absorption capacity, it will do you little good.
There is no doubt that staying hydrated is a critical component. A loss of two percent of total body weight, which is a perfectly realistic percentage when climbing in high temperatures, can significantly reduce muscle performance. However, hydration is only part of the equation, and the pre-climb plan should always include nutritional supplements beyond water.
The reason is that muscle contains a limited amount of glycogen (the form in which muscle stores energy). When glycogen is depleted, muscle performance is dramatically reduced. Even though climbing uses a selective group of muscles, the body cannot recruit glycogen from other muscle groups. In other words, there is no central repository of glycogen in the body to be distributed accordingly to each muscle group that needs it at that moment. When glycogen is consumed in your forearms, it is not easily replenished and prolonged use of the forearm muscles quickly depletes the muscle glycogen store.
Eating food or fluids can delay glycogen depletion by increasing blood glucose levels. Muscles can use blood glucose as a source of energy. The net result is that limited muscle glycogen stores, will be maintained and muscle endurance will be extended.
Glucose is derived from carbohydrate breakdown. Therefore, fluids and carbohydrates are the cornerstones of nutrition in the pre-transition stage. The goal is to increase the blood glucose level before you start climbing. But there is a role for protein as well. Protein has been shown to not only help improve hydration, but minimize the brain fatigue we discussed above.
You can use various combinations of liquid and solid foods to optimize your pre-anode diet, but there are a number of advantages to consuming an isotonic drink that contains protein. It can meet your overall pre-anode needs, is easy to consume and is quickly absorbed by the body. As a general guideline, consume 100-120 calories from a carbohydrate/protein isotonic drink at the start-up stage.
That’s all for now from the first part of our article on the influence of our diet when climbing. In the next article we will go over the next 2 stages, maintenance and recovery and many more tips on protein intake, caffeine and sugar. Until then, feel free to reach out to our gym staff for guidance and to answer any questions you may have!