"Whomever God wills to guide, He renders his chest wide open to
Submission. And whomever He wills to send astray, He renders his
chest intolerant and constricted, as if he were ascending in the sky."
In a research, by Dr Salah Al-Deen El-Magrabi, a member of the American society of Space Medicine, he outlined the condition of the human chest and what happens to it when the human climbs up in the higher layers of the atmosphere. He stated that the vesicles inside our chest play the key role. When we breath, oxygen enters these vesicles causing them to fill up and get enlarged. But if we climb up in the atmosphere the pressure decreases. Consequently, the vesicles shrink, and as a result the chest becomes constricted and breathing becomes more difficult.
It is believed that up to 10,000 feet above sea level the human chest is not affected greatly. From 10,000 up to 15,000 feet the human body tries to adapt itself in an attempt to correct this gradual decrease of pressure.
However from 16,000 to 25,000 feet above sea level the chest suffers badly. At these heights the human could faint, go into a comma or fail to breath altogether.
It is for these dangers that aircrafts are supplied with extra oxygen plus means of adjusting the air pressure inside the plane. These measures are crucial for insuring that the cabin where people are located is adapted for natural breathing as the plane sores at heights of 30,000 to 35,000 feet above sea level.
If there is failure in adjusting the air pressure inside the plane the human would face breathing problems. The stomach gases get expanded and exercise undesirable pressure on the midriff. The midriff in turn exercises pressure on the lungs causing the respiratory system to get suffocated.
This knowledge, is detailed very accurately in the Quranic words:
" ..... his chest intolerant and constricted, as if he were ascending in the sky."
This scientific information is common knowledge in this day and age, however the Quran was revelead 14 centuries ago long before man invented flying machines that could take him to these vast heights to be able to discover this phenomenon.