High elevation prompts physiologic changes in the body. As elevation increases, oxygen concentration in the air decreases; this is why some people suffer from altitude sickness when travelling to high altitude environments like Summit County, Colorado from a lower elevation. Training and/or living at elevation increases our red blood cell mass in order to compensate for the lower oxygen concentration, thus increasing our oxygen-carrying capacity. Red blood cells are like microscopic rafts that flow down the rivers of our blood vessels, picking up oxygen from our lungs when we breathe and then transporting it to all the muscles and organs that need it to function properly. For athletes, this physiologic concept can be used to their advantage in order to improve their performance. If they can train their blood cells to carry more oxygen by forcing them to grow in a more hypoxic (low-oxygen) environment, then they can have more oxygen available to their muscles to perform in any activity.

There is a modern training model that some athletes have adopted called “Live High, Train Low”. This means that the athlete performs high intensity training sessions at a lower elevation, but maintains general training and living at higher altitude. Your body begins making metabolic changes immediately when exposed to high altitude and hypoxia, but it can take a couple weeks for the maximum effect. Expert Dr. Gustavo Zubieta-Castillo, who spoke in La Paz, Bolivia at the 7^th Annual Chronic Hypoxia Conference that Dr. Chris attended in 2019, claims that it takes him about 40 days to build up his hematocrit to be back to functional in La Paz which is situated at nearly 12,000 ft. All in all, the goal of living and/or training high, while including high intensity sessions at lower altitude, is to give your body enough time to build up some acclimatization to the hypoxic environment. Several studies in the last 25 years have taken various groups of athletes and placed them on different training regimens over 4 weeks. Some would live at low altitude and also train low, some trained low and lived high, and others trained high and low while living at high altitude. One study completed in 2008 concluded that athletes who either live high and train low, or live high while training low and high, showed about a 1.4% improvement in sea level endurance performance.

How high is too high, and how low is too low?

It was found in this same study, that there is in fact a “sweet spot” for implementing the “Live High, Train Low” paradigm. If subjects were living lower than 1800 m, there was not a significant improvement in athletic performance. On the other hand, if subjects were living too high, they could not adequately recover from training and therefore did not show improvement because their bodies struggled to keep up with the hypoxic environment. The best elevation to live and/or train at in order to increase RBC (red blood cell) production, RBC mass, and oxygen-carrying capacity is between 2100 m-2800 m, or about 7000 ft-9000 ft.

What does this mean for athletes in Summit County who live high and train high?

Great news! There are still major benefits to those who live and train in Summit Country, as well as for people who visit the mountains and train while they are in town. This is because of a physiologic process called autophagy. Autophagy is described as our cells’ process of degrading old proteins and damaged cell parts. This is a normal process that modulates cell survival, is important for cell renewal, and is also a promoting factor of exercise performance from altitude training.

When exposed to a hypoxic environment, our cells produce adaptive responses that ramp up autophagy and cell renewal elements. These responses include factors that promote skeletal muscle growth, boost skeletal muscle capillary concentration, and enhance coronary arteries (the arteries that feed your heart). Living and training at altitude is good for your heart and it can help build muscle while decreasing body fat mass. It also shows significant increase in cardiac output and strength of your heart stroke.

However, excessive exercise and especially excessive exercise at altitude can prove harmful to our skeletal muscle. It has been observed in male subjects running 20 km that the excessive exercise induces autophagy too much which leads to degradation of muscle protein, damage, and eventual loss of skeletal muscle all together. Therefore, just as there is a sweet spot for altitude training, it is also a good idea to monitor training in order to maximize the benefits of training in a place like beautiful Summit County.

So, how should I be training if I live in Summit County or if I am visiting for some time?

I had the pleasure of speaking with Mary Scheifley about this particular strategy. Mary is the owner of Peak One Fitness, a 24-hour gym in Frisco, Colorado (9000 ft.). She has over 20 years of experience in fitness and athletic training. She competed semi-professionally in mountain bike racing, and continues to bike today as well as cross-country ski, snowboard, weightlift, hike, and anything else that keeps her active. She loves Frisco and has found that being outside and active is almost spiritual. She is passionate about fitness and nutrition, and she works extremely hard to tailor her training regimens to each of her clients based on their individual needs or goals.

When she trained people in Denver, she typically was running high-intensity aerobic classes. However, here in Frisco, she prefers to focus on strength and only include high-intensity interval training (HIIT) in short spurts. She believes that you don’t need to be over-exerting your body to see a positive response. She has a client who lives near sea level for most of the year where her main training regimen includes Cross Fit. When she comes to Frisco though, she can see a significant decrease in BMI and body fat index in just two months of lower-intensity training. Though frustrated that she cannot run on the treadmill as fast or as long as she can at home, by the end of her stay in Frisco, this client understands that difference of the elevation and appreciates the process that Mary provides for her.

Mary recognizes that fitness is not “one size fits all”. She typically likes to start people out at 80% of their maximum heart rate when exercising, but there are factors that may change this. Her clients that live in Summit County have already been acclimatized to the elevation so she can add a little to their 80% max heart rate because for them, 80% may feel like 70%. On the flip side, if you are visiting from sea level, she may have to decrease your 80% of maximum because of the hypoxia at elevation. Other factors that play a role in how Mary develops her training regimens include age, the client’s goals, their previous fitness level, and their overall reaction to altitude.

I also asked Mary about her experience with competition and professional athletes. Personally, she could tell that her endurance was superior to her competition when she raced at altitude against bikers from Denver. She also noticed that when she was in Denver, the racers there were stronger and bulkier than her. She also has experience training athletes who are preparing for competitions such as the Leadville 100 or who are professional skiers who tell her that it is more beneficial for them to come to altitude about 3 weeks prior to competition in order to prepare rather than just training at lower altitude. This is because their body will better adapt if they give it a little more time before competition while training.

At the end of the day, whether you are training for a competition, or just trying to stay healthy, being at altitude can pose challenges as well as benefits to our bodies. The following are some tips from Mary on maximizing your workouts at altitude without compromising your health and wellness.

Mary’s tips for athletic training and exercising at high altitude:

• Increase water intake, even before you come to elevation. You should be drinking at least 3-4 liters of water per day.
• Increase caloric intake. At altitude you are burning more calories than at sea level, and if you are wanting to train you need to fuel your body appropriately. Especially increase protein intake.
• No alcohol. If you enjoy one drink here and there you should be fine, but if you are wanting to train at a high level alcohol should not be on the menu.
• Add electrolytes. In addition to increasing water, you need to make sure you are replenishing your body with the salts it requires.
• Take it slow. Maybe start with some yoga or moderate stretching before moving into running or HIIT classes. You may need to decrease your level of training by 20%.
• Consider spending a night in Denver before heading up the mountain to Summit County. Dr. Chris has expressed this frequently to travelers and visitors of Frisco; it gives your body a chance to acclimatize prior to ascending to 9,000+ feet.
• Don’t expect to be at your “home” level of endurance or fitness. Do not get discouraged if you cannot run your typical 7-minute mile, or you can’t easily warm up with a set of 10-15 squats. Your body needs to adjust, and you may need to just take it easy in the altitude. Ultimately, have fun and enjoy the beautiful outdoors!

Sarah Brzecezk is a 2^nd year Physician Assistant student attending Midwestern University in Glendale, Arizona. She graduated from Northern Arizona University in Flagstaff, AZ with a Bachelor’s in Biomedical Sciences and then worked as a medical assistant in Internal Medicine prior to starting PA School. She is passionate about healthy eating and maintaining a physically active lifestyle, and she hopes to specialize in Orthopedics when she graduates this Fall. During her 6 weeks at elevation in Frisco, Colorado, she has enjoyed numerous hikes, two hut trips, yoga classes, and running in the gorgeous outdoors. Her goal as a provider is to help others overcome injury and illness in order to return to physical activity and athletics, enabling them to combat chronic illness and stay healthy for their future years.

References

Zhang, Y., & Chen, N. (2018). Autophagy Is a Promoter for Aerobic Exercise Performance during High Altitude Training. Oxidative medicine and cellular longevity, 2018, 3617508. doi:10.1155/2018/3617508

Brocherie, F., Millet, G. P., Hauser, A., Steiner, T., Rysman, J., Wehrlin, J. P. & Girard, O. (2015). “Live High–Train Low and High” Hypoxic Training Improves Team-Sport Performance. Medicine & Science in Sports & Exercise, 47(10), 2140–2149. doi: 10.1249/MSS.0000000000000630.

Stray‐Gundersen, J. and Levine, B.D. (2008), Live high, train low at natural altitude. Scandinavian Journal of Medicine & Science in Sports, 18: 21-28. doi:10.1111/j.1600-0838.2008.00829.x