Allah (SWT) says in the Quran: So whoever Allah wants to guide – He expands his breast to [contain] Islam; and whoever He wants to misguide – He makes his breast tight and constricted as though he were climbing into the sky... [Quran 6 : 125] ^[1]


At the time of the Qur’an’s revelation (7th century), no one could have known what happens to the human body at high altitudes — yet this verse describes it precisely.


What happens at high altitude:


As altitude increases, air pressure decreases. The amount of oxygen available in each breath becomes less. Because of this, the lungs struggle to take in enough oxygen. The person begins to feel chest tightness, shortness of breath, dizziness, and sometimes even pain. This is known today as Hypoxia — a medical term for oxygen deprivation at high altitude.


The Qur’an described this physical reaction over 1400 years ago, long before modern science discovered it — a clear sign of divine knowledge.