Why Do I Get Tired Faster in High Altitudes?

tourist woman on the top of mount,

If you get tired faster in high altitudes, it could come simply from having less oxygen to breathe; or, you may be experiencing altitude sickness, which is also known as acute mountain sickness. The majority of people who suffer from altitude sickness experience onset at 14,000 feet or higher; about 20 percent of sufferers will have symptoms at between 6,300 to 9,700 feet, according to PubMed Health. In most cases, the symptoms are mild, but in rare cases it can be life-threatening.


The loss of sleep from altitude sickness can make you feel tired faster; however, your fatigue is mostly likely caused by reduced air pressure and lower oxygen concentration. According to Rick Curtis of Princeton University’s Outdoor Action Guide, you breathe roughly 40 percent fewer oxygen molecules per breath at 12,000 feet than at sea level. Your body still needs the same amount of oxygen to function and must adjust to the reduced oxygen levels. Even though you can feel the effects of less oxygen just sitting still; you increase your risk of developing altitude sickness if you ascend too high too fast, drink alcohol, smoke, are dehydrated or have a chronic lung disease.


The signs and symptoms of reduced oxygen vary in severity from person to person, but in mild cases, you will experience a headache, loss of sleep, fatigue, lightheadedness, an increased heart rate and shortness of breath during physical activity. Altitude sickness is usually mild; however, in severe cases it can lead to life-threatening pulmonary edema or cerebral edema. Some people get altitude sickness, while some people don’t.

Treatment and Prevention

Your body can adapt to increased altitudes, but this process takes one to three days. If you’re experiencing moderate altitude sickness, descend to a lower altitude to prevent the symptoms from getting worse. If you’re at 8,000 to 9,000 feet, drop to 5,000 feet or lower, advises the University of Wisconsin-Madison. If you’re experiencing mild symptoms, stay at that elevation until your body adjusts or descend until the symptoms disappear. Stay well-hydrated at high altitudes and eat frequently. Your diet at high altitudes should consist of more than 70 percent carbohydrates, according to Curtis. Getting extra oxygen will help with symptoms. Commonly prescribed medications are acetazolamide and dexamethasone. In severe cases, hospitalizations may be necessary.


Take it easy while your body adjusts to the oxygen difference. Performing vigorous intensity aerobic activity during altitude sickness may worsen your symptoms. Mild altitude sickness is common; however, if your tiredness is accompanied by confusion, a loss of balance, breathing difficulties, chest tightness and pale or bluish skin, than descend immediately to a lower altitude and seek medical attention.