Athletes and Altitude

Athletes and Altitude

Have you ever heard about runners going to Colorado to train? In fact the US Olympics has a training center located in Colorado - and it's not by coincidence. 

Altitude training is increasing in popularity. It is thought that if you train in an environment where there is less oxygen available that it will result in better performance at sea level and lower elevation. Near sea level is defined as 0–500 m, low altitude is defined as 500–2000 m, moderate altitude 2000–3000 m (most athlete training) and high altitude 3000–5500 m with extreme altitude defined as anything greater than 5500 m. 

Oxidative Stress 

As you increase in elevation the oxygen becomes thinner- meaning your body has to work harder to get more oxygen to our tissues. As you move from an area of lower elevation to an area of higher elevation, our cells undergo something called oxidative stress. Oxidative stress is a normal part of living and happens everyday through basic metabolic processes. However, altitude increases the amount of oxidative stress our cells undergo which can result in delayed recovery. The best way to combat the possible increase in oxidative stress associated with altitude exposure is via the consumption of antioxidant-rich foods. Antioxidants are found widely in fresh fruits and vegetables!

Energy Intake

Adequate energy availability (EA) is an important consideration for both sea-level and altitude training. It has been shown that our resting energy expenditure (REE) (also known as your metabolism at rest) is increased at higher altitudes. This means that your overall calorie needs increase. Recent research shows that poor energy availability can interfere with the body’s ability to adapt to altitude. 

Low energy availability is defined as consumption of less than 30 calories per kilogram per day. This concept of low energy availability has recently been termed relative energy deficiency in sport (RED-S) and has multiple implications in both male and female athletes for iron metabolism, injury and illness, training adaptation and performance. Consequences of low energy availability consist of an increased risk of injury and illness and impairments to reproduction, endocrine function and bone health. That being said, adequate energy availability is defined as roughly 45 calories per kilogram per day and is essential for long-term health and performance. Resting metabolic rate (how fast your body burns through calories at rest) might be only increased by about  300 calories per day at an elevation of 2000 m. However, if an athlete spends 3–4 months at altitude, this actually amounts to about an extra 25,000 calories needed yearly!

Carbohydrates

Studies have shown that the body’s ability to use fat as a fuel source at altitude decreases. While more studies on the impact of carbohydrate metabolism on athletes training at lower to moderate altitudes need to be conducted, training at higher altitudes increases the use of carbohydrates for energy compared to training at sea level. This means that it is important to consume adequate amounts of quality carbohydrates such as sweet potatoes, dates, quinoa, brown rice, oats, lentils, beans and other grains when altitude training. These foods also help to increase calorie consumption and overall energy availability. 

Iron

Iron needs to increase in altitude. Increased iron requirements at altitude is another factor that can interfere with the body’s ability to adapt to altitude. Data shows that there is a decreased production of red blood cells that is observed in non-iron supplemented athletes during simulated altitude studies. Hemoglobin is a protein that is found in red blood cells that transports oxygen to cells, muscles and tissues. When oxygen is thinner and not as readily available (as in a higher altitude state), our body tries to produce more hemoglobin so that we can get more oxygen to our tissues. But, in order for our body to produce more hemoglobin, it must have iron.

Think about it like this. Hemoglobin is the bus that transports oxygen from our lungs to our body and iron is the bus driver. If there are not enough bus drivers (iron) then there are less buses (hemoglobin) to transport oxygen to our cells, tissues and muscles. When we increase our altitude our tissues and muscles require more oxygen and our body brings more buses on board (hemoglobin). However, our bodies cannot bring on more buses if it does not have enough bus drivers (iron).  For this reason, coupled with the increase in red blood cell breakdown that results from high intensity training and exercise, it is essential to make sure you have adequate iron stores before engaging in high altitude activities. It is recommended to get baseline iron levels tested 4-6 weeks before altitude training, and ensure that you talk with your doctor about getting on an individually tailored iron supplementation protocol while at altitude. You can also increase your iron intake through food sources such as eggs, fish, chicken and steak.

Hydration 

 

Athletes should consider altitude training a time of increased risk for dehydration and both monitor and address their hydration status appropriately. Some signs of dehydration to look out for include fatigue, increased thirst, headache, dizziness, dry mouth, or decreased urine output.

Hypoxia (low oxygen levels) and the low air humidity associated with altitude environments are likely to increase fluid losses at rest and during training. Increased respiratory water loss and increased urine output are often seen in the early response to altitude exposure and can create a significant increase in water requirements. Hydration needs will vary from person to person, but most often athletes will need to increase consumption by 25-50% (0.5 liters to 2.5 liters extra) compared to normal intake. Increases in hydration requirements depend on altitude and level of training intensity. Finding your level of optimal hydration can be observed via urine color and output frequency. Remember that a pale yellow signifies adequately hydrated urine and dark yellow to amber signifies under- hydrated/dehydration.

Don’t forget about electrolytes! 

A number of high altitude-related syndromes are associated with abnormal salt and water retention. With an increase in hydration needs due to increased water loss through sweat and respiration at altitude comes an increased need for electrolyte repletion. Make sure to refuel with electrolytes as well as water when training at altitude. 

Supplements

It is important to note that performance enhancing supplements (also known as ergogenic aids) are of extreme interest to athletes. However, more research is needed to test the effectiveness of these supplements on athletes at altitude. Herbal supplements to increase immunity in athletes training at altitude have also been of interest. However, more research is needed to determine effectiveness, dosage, and duration. 

Training at altitude is a popular practice among athletes. Most of the studies that exist are on athletes training at extreme altitudes and therefore more studies need to be done on the impacts of training at low to moderate altitudes and nutritional recommendations. Ann article by team USA stated that research has found that most issues related to altitude training are actually related to the increased training stress, frequency and duration, and weather conditions rather than the altitude itself.

Take-Aways 

When traveling to altitude for training, whether by car or plane, it is important to go into travel with optimal hydration, energy availability, and rest to help curve jet lag and support your immune system. Upon arrival at altitude, it is important to ease into training and watch for signs of altitude sickness. Signs of altitude sickness include: GI distress, headaches, dizziness, shortness of breath, and tiredness. Ease into the first 3-5 days of training and make sure to stay hydrated. Eating the right amount of calories to fuel your training as well as replenishing and repleting your stores after training is more important than ever at altitude to make sure your body has enough available energy to recover as well as refuel. To help ensure that you are fueling yourself, your activity level, and your training properly, it is advised to see a registered dietitian or nutrition professional.

Tips to eating well while altitude training 

Know before you go! We know that energy availability- or the amount of energy your body has for recovery after training is critical at any altitude. However, it is even more critical when training at altitude as low energy availability can prolong recovery, impact performance, increase the risk of injury and illness, impair reproduction and endocrine function and negatively impact bone health. To help ensure you are consuming enough food while training, it is important to think about your meals beforehand. Ask yourself these questions: 

Have I planned for meals?

When will meals be?

How will I be getting my food?

Will I have access to a kitchen or stove? 

Do I need to bring extra food with me?

Will I be sharing accommodations/meals? 

Do I know my individual nutritional and calorie needs?

Ensuring adequate calories while altitude training can make or break your training. It is important to remember that if you are attending an altitude training camp or will be training in a group that results in sharing accommodations, that it is likely your nutrition practices will be altered. If this is the case, discuss meals with the group and make a plan beforehand to help ensure adequate calorie consumption and energy availability.

Written by Emily Ekanger, MS, Dietetic Intern