This story originally appeared in the July 2015 issue of our print edition.
From everyday diet to lightweight gear to mental technique, climbers are always looking for any little detail that might give them a performance edge, and physiology, or the study of the function of living systems, has been a factor in pushing climbing forward for a century. For example, it was physiologist Griffith Pugh’s seminal work on exercise performance at altitude that allowed Tenzing Norgay and Sir Edmund Hillary to summit Everest in 1953. Recently, numerous university studies have suggested that dietary nitrate supplementation (particularly via beetroot juice) may benefit athletes both at sea level and altitude. As climbers we consistently utilize a full spectrum of low- and high-intensity movement in various environments. For boulderers, supplementation could afford the extra muscular force needed to stick a difficult move. Sport climbers may notice the ability to push through a tough sequence and still have enough stamina to finish the pitch. Alpinists could see sustained improvement at high altitude, and they should have more endurance for hanging on ice tools during technical ice climbing. Basically, nitrate supplements equal better overall performance, no matter your chosen climbing discipline. Here we outline how it works and how you can use it to enhance your performance both at your local crag and on your next alpine adventure.
Increasing Oxygen Delivery
At rest and during low-intensity exercise, our muscles use oxidative metabolism to create the energy needed for muscle contraction. This type of metabolism utilizes fat and, like it sounds, relies heavily on the availability of oxygen delivered by our blood. The nice thing about oxidative metabolism is that it is sustainable due to the abundance of energy available from fat, allowing us to continue to exercise at low intensity for long durations.
During exercise, our muscles require an increase in blood flow to meet the increased metabolic demands. Nitric oxide (NO) is a key molecule responsible for increasing blood flow to our muscles. When produced, it dilates (enlarges) blood vessels, allowing blood to flow at a higher rate (much like turning on a water faucet). Failure to deliver adequate oxygen to our muscles results in a switch to glycolytic metabolism, which relies on carbohydrates, and produces lactate and hydrogen ions (acid), thus sowing the seeds of muscular fatigue. Therefore, sufficient blood flow during exercise is crucial to maximize muscular performance and endurance.
Supplementing with Nitrate
Luckily for us, we can increase the availability of NO simply by increasing the amount of nitrate in our diet. When nitrate (NO₃₋) is ingested, it enters your blood circulation through the stomach and is then taken up by your salivary glands and secreted into your mouth, where it is reduced to nitrite (NO₂₋) via good bacteria that live there. The NO₂₋ is then swallowed, absorbed into your blood, and then further reduced to NO. This results in greater blood flow during exercise, a reduction in blood lactate production, improved muscle force, and ultimately enhanced exercise capacity by as much as 18%. It also increases the efficiency of mitochondria (the primary energy producers in muscle cells), effectively reducing oxygen demand in the face of improved oxygen delivery. This is kind of like increasing the gas tank in your car while also improving the fuel economy of the engine.
While most studies on improved athletic performance from nitrate supplementation have focused on beetroot juice, there are a plethora of green, leafy vegetables that can provide sufficient amounts of nitrate, like spinach or arugula. Below are some guidelines of when to take the supplements and how to maximize its effects.
- Effects are optimal about 2 to 3 hours following consumption (not like most pre-workout supplements that recommend 15 to 30 minutes before exercise) of about 8 to 9 millimoles (a millimole is a measure of concentration) of nitrate, which translates to about 100 to 200 grams (½ cup to 1 cup) of spinach or 200 to 300 grams (1 cup to 1½ cups) of lettuce. For beet juice, you need about ½ to 1 liter to get this amount, which is quite a bit, but there are concentrates available (see below). There is no added benefit to consuming more than this amount (i.e., more is not better).
- Many athletes use a concentrated version of beetroot juice available from James White Drinks (jameswhite.co.uk or luckyvitamin.com). Each shot packs about 4 mmol of NO₃₋ into 70ml of juice (about one gulp). This is a quick and convenient way for athletes to consume the requisite amount for physiological benefits, and it’s easy to bring the supplement along on excursions. For best results consume two shots. If you have a juicer, you can make your own nitrate-rich drink by throwing in a few beets, carrots, and some spinach.
- Boiling or cooking beets and/or spinach is also an option. Saving the water used to boil beets can be an excellent way to capture additional nitrate and can be consumed at a later time. Think of it like making your own sport shot.
- Some of the effects of nitrate supplementation can be elicited within 3 hours of consumption, while some may take several days (about 3 to 6) to develop. This may be because it takes multiple days of increased NO₃₋/NO2₋ levels to elicit key protein changes in skeletal muscle and the cardiovascular system. It’s advisable to try this supplement regularly before climbing for a few weeks to reap maximum benefits,
- Consume your nitrate-rich meal/supplement at least 2 to 3 hours prior to starting your ascent. This affords enough time for it to enter the blood stream, get secreted into the mouth, and be reduced to nitrite by the bacteria in your mouth. Studies also show that using antibacterial mouthwash completely abolishes any effects of supplementation, so ditch the Listerine on supplement days.
- The boost in performance or stamina won’t last all day. In fact, it will likely diminish within 8 to 10 hours of drinking your juice or sport shot. To prevent this, make two daily doses; take one a couple hours before you start climbing and one at lunch.
- Nitrate is consumed
NO₃₋ is absorbed and secreted into the mouth by our salivary glands. It’s then reduced to NO₂₋ via facultative bacteria.
- Increased 0₂ delivery
- Decreased lactic acid
- Decreased 0₂ demand
NO₂₋ is then reduced to NO, which dilates blood vessels thus increasing oxygen delivery. NO also increases the efficiency of mitochondria, which are the main energy producers in our muscles.
- Peak performance
Reduced O₂ demand means increased ability to sustain exercise (e.g., more energy after a long approach). Increased blood flow reduces the accumulation of fatigue-associated metabolites (like lactate).
Scott Ferguson has a master’s degree in kinesiology and is nearing the completion of his doctorate in exercise physiology at Kansas State University, with a focus on the impacts of nitrate supplementation on exercise performance.