Question

How could spending 2 weeks at 18,000 ft put a person into negative nitrogen balance?

Answer 1

- 18000 ft is a very high altitude. At such high altitudes the partial pressure of oxygen in the atmosphere is very low.
-This results in hypoxia.
- Also at high altitudes the appetite is affected resulting in reduced hunger and desire to eat.

- At higher altitudes low oxygen availability results in higher respiratory rate and increased load on cardiovascular system which increases the metabolic activity of body cells. The body needs more energy which is derived from carbohydrates and fats.
- But once the carbohydrates and fat stores deplete the body switches to proteins stored in muscles for energy. This results in reduced muscle mass.
- All these factors reduces the body weight.
- high altitudes also results in diuresis which cause loss of nitrogen in urine.
- The above factors also results in imbalance between the nitrogen intake and nitrogen loss.
- The nitrogen intake is reduced due to reduced appetite and desire to eat. But the nitrogen loss through urine and mobilizing protein stores for energy increases nitrogen loss.
- In such a scenario where nitrogen loss exceeds the nitrogen intake results in negative nitrogen balance.