Altitude training camps have long been the secrets to success for many athletes. Escaping to remote areas at 5,000 feet plus of elevation for weeks at a time can reap many benefits for a person’s fitness. Taking the cardiovascular gains you receive at elevation to a performance at sea level, and an athlete can feel like an entirely different person! The question is: how can we determine as athletes or maybe even as coaches, determine if we are receiving the benefits of altitude or experiencing the negative effects? Recording and tracking biometrics such as RHR and SpO2 can help us determine altitudes’ effects.
Most people can say that if they have ever been to a city or town at altitude, some tasks are a little bit harder to perform. Tasks such as walking up stairs and hiking have all the sudden become much more difficult than when you were 1,000 meters lower. Why is this?
The quick and dirty answer that some may rattle off that there is less oxygen at altitude than at sea level. This statement is false. There is the same amount of oxygen at 6,000 feet as there is at 200 feet. The different is the atmospheric pressure at elevation. When a person is at sea level, the atmospheric pressure is at 14.7 pounds per square inch. What does that mean? It means, that oxygen can easily pass through a membrane in our lungs and enter our blood. At altitude, let’s say at 5,000 feet of elevation, the atmospheric pressure is at 12 pounds per square inch. This lower air pressure makes it much more difficult for oxygen to enter the vascular system of our body, thus making us feel more out of breath at a similar effort. Now let’s just think about what it must feel like on the top of Mount Everest, with an atmospheric pressure of about 4.2 pounds per square inch!
Training At Altitude:
Training at elevations greater than sea level can impose changes to a person’s daily training regimen. Since altitude has a difference in the atmospheric pressure as discussed above and we have a harder time processing oxygen to our blood, this means that our body’s carry less oxygen in our blood to our working muscles. With this decrease in oxygen to the working muscles, this reduces our body’s ability to work at it’s absolute aerobic capacity. What does this mean for us? It means that at elevation, we are not able to hit our absolute maximum efforts due to the reduction of oxygen in our working muscles. Workouts that are made to target maximal effort would have to take into account the elevation, if you were to compare the same effort to one performed at sea level. For example: for a runner to perform a workout that is 5×1000 meter repeats and they run each repeat in 3:30, this would be equivalent to the same runner performing this workout at 5,000 feet of elevation and running 3:40 per interval. Though the effort is the same, the body is unable to run at the same speeds and recover in the same time period. If the runner were to do this same workout at altitude and complete it in 3:30, they would be exerting more of an effort, or “digging deeper”, this type of effort repeated can lead to overtraining in individuals.
Biometric Measurements at Altitude and What We Can Learn:
When training at altitude, it is important to track biometric data so that we can see trends develop in our fitness. These data trends can give us better insight into how our bodies are responding to altitude and if we need to make changes. Some biometrics may be suited for specific athletic endeavors such as high altitude climbing:
SpO2: For people who partake in high altitude climbing, SpO2 sensors can be beneficial in determining a few different factors. One factor would be monitoring for AMS, or Acute Mountain Sickness. AMS can happen to individuals who are unhealthy and healthy. AMS does not have to occur when high altitudes either, it can affect individuals at low altitudes as well. Effects of AMS can include headaches, lightheadedness, and general illness at saturation levels of even 94%. Normally, a healthy individual’s SpO2 measurement is 99%, so a decrease in 5% doesn’t seem like much, but in AMS it can be enough to kickstart symptoms. When hikers begin to drop large percentages in their SpO2 that is when more severe symptoms can occur. Individuals can lose consciousness, and potential brain cell death when dipping below the 55-40% range. In the long term, AMS can lead to conditions such as High Altitude Pulmonary Edema, where fluid collects in your lungs.
To help combat this, and to ensure you know where your body stands at all altitudes, climbers can use Pulse Oximeters to read their oxygen saturation levels. Having the ability to read low SpO2 levels can help a climber determine if it is in their best interest to descend to get back to lower elevation or if their body is adapting to continue climbing. It is good to point out that at high altitudes, even the best pulse oximeters can come up with incorrect readings, so it is always best to listen to your body!
Resting Heart Rate: As discussed earlier, the amount of blood your working muscles receive at altitude is limited. Due to the limitations on oxygenated blood, our body’s cardiovascular system tries to combat this by increasing our cardiac output. [Cardiac Output = Stroke Volume x Heart Rate] This is to help get more blood pumping throughout our system in an effort to supply enough oxygen to our muscles. As we arrive at altitude and acclimate, our heart rate is increased due to the change in atmospheric pressure. At the same time our stroke volume is decreased during work. As we remain at altitude for longer periods of time, trends in our resting heart rate will begin to form. You should see your RHR begin to decrease back to the same values as they were at sea level. When you begin to see this trend, this is when acclimatization is occurring. This process can take up to two weeks, and sometimes more in certain individuals.
Tracking your RHR trend therefore can help you determine when you body has finally become adapted to altitude. Prior to acclimating, if you push training workouts too hard, it may increase your risk for injury or overtraining. As stated before, each person acclimates differently from another, therefore every person’s training program may be different. Keeping track of relevant information such as fatigue levels, perceived rate of exertion, resting heart rate (taken each morning), can help shape a training program that is tailored specific to an individual’s’ needs.
Many professional and amateur athletes have discovered the benefits of altitude. There are hundreds of research articles backing up the positive effects higher elevation can have on performance. On the flip side, there are also studies to show that the effects of altitude are not always for a benefit. Today, we have biometric trackers can help us make this choice on our own. Whether you’re a competitive runner looking for the extra edge, or a climber looking to seek your personal limits, science and biometrics has a place in your daily training.