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Climbing is a long and demanding endeavor, with a typical summit day on Rainier or Denali stretching for twelve to fifteen hours. Every time you take a step, your muscles require energy in the form of ATP to be able to fire. ATP is created within the muscle cells by mitochondria from two main nutrients: carbohydrates and fat.

For many years, athletes have focused on their carbohydrate intake as the key to performance. Carbohydrates provide a readily accessible and easily digestible energy source for your body, which is the reason that they are the main content in most sports foods; just look at the labels of shot blocks, Gu’s, bars, energy drinks, and the like, and you will see a heavy focus on sugar. There is a good reason for this: your body has a limited ability to digest food while exercising (digestion requires energy of its own), and carbohydrates and sugars are the easiest to digest, requiring little to be done to the glucose components before they enter the bloodstream and are carried to the cells.

The main issue with a reliance on carbohydrates is that your body has the ability to store a finite supply of glucose in the muscle cells and the liver in the form of glycogen. For trained athletes that are efficient with their energy usage, that store still only lasts for about 2 hours of sustained hard effort. If you aren’t familiar with the term “bonking,” it’s that feeling when your performance drops off a cliff; you don’t feel like you are working that hard aerobically, but you can’t possibly go any faster or harder. You’ve run through those glycogen stores and your muscles are out of fuel. Eating while you exercise can help to delay bonking, but your body can only process about 250 Kcal of sugar per hour, far less than you expend over the same period. Even though we are replenishing our sugar fuel, we dip further and further into those reserves as summit day goes on. At the same time, even the leanest among us carries over 24 hours of energy in the form of fat stores. Wouldn’t it be nice to recruit those stores while you are climbing?

Fatty acids are the most energy dense nutrients in our diet and our body stores them readily. They create more ATP per unit than sugars, and our body’s ability to store them can leave us with a huge reserve energy supply. The problem is that when fatty acids and sugars are both present, our metabolisms preference burning the sugars for energy. Julia Goedecke is a sports scientist who has been examining the influence of fat oxidation (metabolism) in endurance athletes. In examining rates of fat oxidation in athletes at different intensity levels, she found a vast difference in overall rates of fat oxidation. Some burned nearly no fat at rest, while others metabolized nearly 100% fat at rest, but while there were differences in overall rates of fat metabolism, those who metabolized more fat at rest derived more of their energy from fat at all intensity levels too. This would suggest that if we can train our metabolism to derive a greater percentage of our energy from fat, it will continue to do that as we up our intensity climbing, and we will use our sugar reserves more slowly, and hopefully avoid the dreaded “bonk!”

Now that we’ve introduced the idea of developing your fat metabolism, stay tuned next week as we get into the details about how to accomplish it.

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For more reading Alan Couzens has a number of interesting blogs on the subject. A good one to start with is Improving Fat Oxidation.

Questions? Comments? Do you have experience applying LCHF nutrition to endurance sports? Share your thoughts here on the RMI Blog!

The Four Day Climb August 29 - 1 September was unable to reach the summit today due to route conditions.  RMI Guides Pete Van Deventer and Dominic Cifelli lead their teams to Ingraham Flats at 11, 200', they enjoyed the views as the sun came up.  The team is now back at Camp Muir and will begin their descent to Paradise later this morning.

Hello all,

Today we woke to perfect weather to hit the trail. A mellow walk past yak corrals took us to our first uphill. A little more breathing and some sweat brought us to a downhill trend to the river crossing. Before we crossed, the team enjoyed an ice cold foot soak. Shortly after the river it was tea time. The saying out here might go Dal Bhat power 24 hour but I think for us its hot tea power 24 hour. After filling our energy tanks with tea we madr our way up the last hill of the day. The top of the hill brings us to a special place, the climbers memorial. A sadness fills this place but also brings to reality the risks taken to climb mountains. After acknowledging those who have fallen we continued our journey to Lobuche. Not far from the town we pass by the Lobuche peak Basecamp. We gaze at our objective but first we must go to Everest Basecamp. A little training in the evening brought us to dinner. A birthday cake surprise wrapped up our day with smiles and chocolate covered mouths. Another good day in the books and more to follow. 

Goodnight all,

RMI Guides Adam, Hannah, and team

High Intensity Interval Training, often referred to popularly as HIIT training, have been featured in a few recent studies that concluded that a short HIIT workout was as or more effective at promoting cardiovascular health than steady state activity. The first paragraph of a recent New York Times article reads:

Think you’re too busy to work out? We have the workout for you. In minutes, high-intensity interval training (HIIT) will have you sweating, breathing hard and maximizing the health benefits of exercise without the time commitment. Best of all, it’s scientifically proven to work.

Despite the recent attention, interval training is not anything new to seasoned athletes and coaches who have understood the benefits of repetitive high intensity workouts for a long time. Many of the recent studies have focused on previously sedentary people trying to improve basic cardiovascular health, rather than on elite athletes striving towards a performance goal. With that said, we have and continue to encourage climbers to utilize interval training (by it’s nature high intensity) as part of a well-designed training program.

Interval training can accomplish a wide array of tasks and works best when the focus of a workout is clear:

Longer intervals, from 5 to 8 minutes, at 70 – 85% of max heart rate work to improve the lactate threshold, the body’s ability to metabolize and clear lactate build up from muscle cells, increasing the amount of work that the body can perform sustainably. A good example is an elite level marathon runner, who is able to sub six-minute miles for over two hours during a race. The intensity that they are working at is very high, yet the body is able to sustain it over a very prolonged period of time.

Shorter intervals, from 20 seconds to a few minutes, performed at 85 – 95% of max heart rate (very intense!) increase the body’s anaerobic threshold, it’s ability to perform work while in oxygen deficit. Think Olympic swimmer in the 50-meter butterfly: the intensity that they race at surpasses the body’s ability to clear lactic acid and to provide enough oxygen to the muscle cells for them to continue that pace for a long period of time. The race is very short, however, and for that 20-something seconds, their muscles are able to put out an immense amount of power in oxygen deficit.

It may seem as though interval training isn’t as applicable to our sport of mountaineering. We tend not to sustain the very high levels of output, but instead operate for far longer periods at moderate intensity. It is the very definition of an endurance sport. Interval training provides other physiological adaptations however that go beyond the abilities of the skeletal muscles. Interval training is shown to increase cardiac output, by increasing the size of the left ventricle, the stroke volume and the overall contractility of the heart. Increased cardiac output supplies more blood to muscle cells, delivering more oxygen and removing more waste. Additionally, interval training has been shown to increase the size and density of mitochondria in the muscle cells. Mitochondria use oxygen to convert glucose to ATP (the cells’ energy source). Both of these adaptations help endurance athletes go longer, faster and with less effort, and ultimately help us in the mountains.

Interval training is harder on your body than traditional steady state workouts and requires longer to recover from as well. Therefore, too heavy of a focus on interval training can lead to overtraining and injury. More of a good thing isn’t necessarily better. It’s important to realize that a good training plan maintains a balance of high intensity workouts and lower intensity steady state workouts.

As part of the recent HIIT hype, people have championed the fact that HIIT gets more done in less time, even as little as 10 minutes. This may be true for an average person whose goal is to improve overall cardiac health, but for athletes working towards goals in the mountains, remember that there are no short cuts. Time invested in your training will lead to a more enjoyable and successful climb.

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Questions? Comments? Share your thoughts here!