What Is High Altitude Adaptation?
High altitude adaptation is the ability of a human being to survive at extremely high altitudes. People who have lived for generations together at high altitudes have gone through certain genetic and behavioral changes to help them adapt to extreme climatic conditions.
What Happens At High Altitudes?
Human beings are generally adapted to living in lowlands where oxygen is available in plenty. Oxygen is essential for the functioning of the body and the brain. When you travel to highlands, at altitudes above 2500 meters, the body experiences sudden oxygen deprivation. At about 4000 meters, you get only 62% of oxygen in each breath from the atmosphere, compared to 100% at sea level. This leads to altitude sickness.
Symptoms Of High Altitude Sickness
- Dizziness
- Breathing difficulties
- Headaches
- Nausea and vomiting
- Dilated veins
- Increase in blood pressure
The condition that results because of a lack of essential oxygen to the body is called hypoxia. Hypoxia can turn fatal when oxygen levels are consistently low for extended periods of time.
Adapting To Higher Altitudes
About 2% of the world’s population live in extremely high altitudes above 8,200 ft. People from Tibet in Asia, Ethiopia in Africa, and the Andes in the Americas have all acquired the physical ability to avoid the above-mentioned symptoms and survive healthily in high altitudes.
The Importance Of High Altitude Adaptation For Olympic Trainers
It is common knowledge that aerobic performance declines at higher altitudes. During the Olympics game held in Mexico in 1968, coaches saw that the performance of their athletes declined during the practice sessions and the actual competition. The high altitude of about 7,500 ft had brought down the performance of most athletes that year.
After this, coaches started reaching high altitude venues several weeks ahead to help performers get used to the high altitude and improve their endurance. This is called acclimatization.
Even now, high altitude training is a common practice for endurance trainers like swimmers and runners to improve their performance.
Generally, when athletes perform at high altitudes, their muscles receive less oxygen with each breath. This is what brings down performance. As athletes start training extensively in high altitudes, the body starts producing more Red Blood Cells (RBCs) to help carry more oxygen to the muscles.
The increased RBC count gives a 1-2 % performance boost to the athletes at lowlands. This may not seem much, but when the difference between winning and losing is just 1-2 seconds, even a 1% performance boost makes a lot of difference.
Cognitive Ability In Athletes At Higher Altitudes
Many studies have analyzed the effects of high altitudes on cognitive ability. A 2004 study concluded that at higher altitudes, problems like visual hallucinations, lowered accuracy, impaired motor functions, and slower decision-making skills are commonly observed. At
altitudes higher than 6,000 m, people experience short-term memory, too.
Unless the body and the mind are prepared to handle these, a reduction in cognitive ability can impact the performance of athletes and trainers.
How Does Genetics Influence High Altitude Adaptation During Training?
EDN1 Gene
The EDN1 gene encodes for the Endothelin 1 protein. This protein helps in relaxing blood vessels and thereby bringing down blood pressure levels.
A study compared the ability to adapt to higher altitudes between high altitude natives and sojourners people who temporarily travel to higher altitudes.
rs2071942
The GG genotype of the SNP rs2071942 of this gene is associated with higher altitude adaptation. This allele was also more favorable during acclimatization.
ADRB2 Gene
The ADRB2 gene encodes for the beta-2-adrenergic receptor and plays an important role in signaling in the body. Mutations in this gene can cause breathing difficulties and asthma.
ADRB3 Gene
The ADRB3 gene too plays a role in signaling and helps distribute heat energy in the muscles and tissues of the body.
rs4994
The TT genotype of the SNP rs4994 of this gene is associated with higher altitude adaptation when compared to the CC genotype.
VEGFA Gene
The VEGFA gene encodes for the Vascular Endothelial Growth Factor A protein. This protein is important in the formation of blood vessels and endothelial cell growth and maintenance.
rs3025039
The CC genotype of the SNP rs3025039 of this gene is associated with higher altitude adaptation.
Non-Genetic Factors That Affect High Altitude Adaptation In Trainers
Home elevation - Trainers who are used to living at sea level find it difficult to adapt to acute higher altitudes than those who are used to living in higher lands.
Age - Older trainers and athletes find it difficult to adapt to higher altitudes when compared to younger individuals.
Pre-acclimatization - Acclimatization is the process of giving the body time to adjust to a new environment (high altitude in this case). Pre-acclimatization is getting a trainer used to higher altitudes before getting him to perform with the usual intensity. Trainers who have gone through pre-acclimatization find it easier to handle high altitudes than those who haven’t.
Pre-existing health conditions - People with pre-existing health conditions find it difficult to adapt to higher altitudes than those without these issues. Some of the conditions that can affect high altitude adaptation in athletes are:
- High blood pressure
- Arrhythmias and congenital heart conditions
- COPD
- Migraine
- Obstructive Sleep Apnea
Dehydration - Dehydration while training at high altitudes can make the symptoms of altitude sickness worse.
What Can You Do To Improve High Altitude Adaptation?
High Altitude Training
If you have only been training in the lowlands, it is vital you consider high altitude training too. This will improve your efficiency and also get you equipped to perform in higher terrains.
Nutrition
Acclimatization
Reaching the high altitude terrain early and getting used to the lowered amount of oxygen molecules in the atmosphere will help the body adapt to the changes naturally. Acclimatization is a very important part of Olympic training. Studies show that when you spend more days in acute altitudes, the submaximal performance peaks and stabilizes.
Summary
- High altitude adaptation is the ability of human beings to handle low-oxygen levels in the atmosphere. Natives who have lived in high altitudes for generations have genetic and behavioral changes in the body to help handle the altitude.
- When you ascend a hill or a mountain, altitude sickness is a common problem. Symptoms include dizziness, nausea, breathing difficulties, and an increase in blood pressure.
- Trainers and athletes find their performance declining in higher altitudes. The inability of the body to inhale enough oxygen causes this.
- Acclimatization is the process of getting to highlands early before a competition and letting the body get used to the low-oxygen levels. Some trainers and athletes start the process of acclimatization weeks early.
- Mutations in the EDN1 gene, ADRB2 gene, ADRB3 gene, and VEGFA genes affect the ability to adapt to higher altitudes.
- Home elevation, pre-existing health conditions, and age can also affect the ability to handle higher altitudes in trainers and athletes.
- Training in higher altitudes, going through the process of acclimatization, and making the right changes in your nutritional intake can all help improve high altitude performance and efficiency.
References
https://utswmed.org/medblog/high-altitude-training/
http://www.altitudemedicine.org/altitude-and-pre-existing-conditions
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2965377/
https://en.wikipedia.org/wiki/High-altitude_adaptation_in_humans#Genetic_basis
