Question
A healthy, non-acclimatized woman travels from Delhi (sea level) to Leh (approximately 3,500 m above sea level). Soon after arrival, she develops dyspnoea (shortness of breath). Which of the following statements best explains the cause of her symptoms?
| A. |
She is hypoventilating; and that makes her dyspneic
|
| B. |
Atmospheric Oxygen in Leh is lesser than that in Delhi and that makes her hemoglobin to deliver less oxygen to tissues; causing dyspnoea
|
| C. |
She is hyperventilating; causing dyspnoea and Respiratory Alkalosis
|
| D. |
Atmospheric Oxygen in Leh is higher than that in Delhi and that makes her to experience dyspnoea
|
Show Answer
|
Correct Answer » B
Explanation
|
|
At high altitudes like Leh (approx. 3,500 meters), the atmospheric pressure is significantly ↓ than at sea level (e.g., Delhi). This causes:
– ↓ partial pressure of oxygen (PO₂) in the air
– Leads to ↓ alveolar & arterial PO₂
– Results in ↓ oxygen saturation of hemoglobin
– Ultimately, less O₂ is delivered to tissues, triggering dyspnoea (breathlessness)
This type of hypoxia is termed “hypoxic hypoxia,” seen in acute high-altitude exposure, particularly in non-acclimatized individuals.
Incorrect Options:
A. Hypoventilation – The body hyperventilates in response to hypoxia, not hypoventilates.
C. Hyperventilation – Hyperventilation occurs but dyspnoea is due to tissue hypoxia. Respiratory alkalosis is secondary.
D. → Altitude puts ↓ atmospheric O₂, not ↑.
