The effects of high altitudes || What are the Effects of high altitude on humans?

Effect of Altitude on the Heart and the Lungs | Circulation:

What are the Effects of high altitude on humans?

The lung at high altitude:

High-altitude (HA) environments have adverse effects on the normal functioning body of people accustomed to living at low altitudes because of the change in barometric pressure which causes decrease in the amount of oxygen leading to hypobaric hypoxia. Sustained exposure to hypoxia has adverse effects on body weight, muscle structure and exercise capacity, mental functioning, and sleep quality.

The effects of high altitudes: on the human body are extreme: the region in the Himalayas above about 25,000 feet (7,600 Metres) is known as the “death zone.” Climbers at such high altitude have much more rapid breathing and pulse rates (as their bodies try to obtain more oxygen). In addition, they are not able to digest food well (and often find eating unappealing), they sleep poorly (1*), and they often find their thinking to be confused (2*). These symptoms are manifestations of oxygen deprivation (hypoxia) in the body tissues, which makes any effort difficult and can lead to poor decisions being made in an already dangerous environment.

Oxygen at HA:

HA that reflects the lowered amount of gases including O2 in the atmosphere is defined as:

(i)      intermediate altitude: 1500–2500 m;

(ii)     HA: 2500–3500 m;

(iii)    very HA: 3500–5800 m;

(iv)    extreme altitude: above 5800 m.

1* Sleeping :: At altitude, the reduced oxygen content of the blood induces breathing instability, with periods of deep and rapid breathing alternating with central apnea. This breathing pattern is called high-altitude periodic breathing (PB). It occurs even in healthy persons at altitudes above 6000 ft. It may lead to sleep disturbances with frequent awakenings and a feeling of lack of air [29]. De Aquino Lemos et al. found that hypoxia reduced total sleep time, sleep efficiency, slow-wave sleep, and rapid eye movement. Depressive mood, anger, and fatigue increased under hypoxic conditions. Vigor, attention, visual and working memory, concentration, executive functions, inhibitory control, and speed of mental processing worsened.

2* Mental Situation:: HAs of more than 3.000 m produce physiological disorders and adverse changes in moods and cognitive/motor performance of nonacclimatized individuals [3]. It is known that exposure to HA can produce adverse effects in motor skills, mental efficiency, and mood states, including anxiety depending on the altitude level reached, the speed of the ascent, and the time spent at HA [26, 27]. Most people working at an altitude of 4000 m experience an increased number of arithmetic errors, reduced attention span, and increased mental fatigue. Visual and auditory sensitiveness and short-term memory are negatively affected by exposure to an altitude of nearly 2500 m.