Walking for hours without haste, in a healthy environment, where the air is clean, has a positive impact on all aspects of muscles, joints become loose and hearts and lungs will derive great benefits.
The cardiovascular system in particular is the one who receive the most worthwhile effects of trekking.
The heart gets used to support a job not intense but prolonged, so its walls, consisting of muscle tissue, works better.
This involves an enormous advantage because it increases blood the heart can pump to each beat and therefore decreases the speed at which the heart must beat to provide adequately day oxygen throughout the body.
In addition, the blood-vessels grow and become more flexible so blood pressure lower. This brings great benefit to the whole body, heart and muscles.
With the trek also improves the respiratory function. When you walk a long-time, the frequency of respiration, inhalation and exhalation, increase and, in particular, increase their size so each inspiration introduces into the lungs a greater volume of air.
The path in this photo seems to go pretty high up, although I may be wrong. Do/can people trek that high? Would there be any respiratory issues because of elevation? I ask because I've walked a bit on Pike's Peak and Mt. Evans in Colorado, and noticed it took a little more work than usual to breath (although nothing that threatened my well being), because of less oxygen at such a height (around 14,000 ft)
They walk nearly two miles, around 9,500 hundred feet, that's pretty high up there. It's actually only about 5,000 feet lower than some of the peaks I was on in Colorado. That's a pretty impressive trek.