The mountain is one of the most popular holiday destinations. Relaxing greenery, walks and landscapes regenerate the mind and body, but it is necessary to pay attention not only to the altitude, but also to the speed with which a certain height is reached and to stay at that height. In fact, the risk does not only concern the rise in blood pressure, but also the possible onset of mountain sickness (Acute Mountain Sikness, AMS), a general malaise due to the reduction of oxygen in the body and which generally occurs above 2,500 meters of share.
At high altitudes (above 2500 meters) there is a condition of hypoxia, i.e. reduced availability of oxygen to the tissues and organs, which can induce a pressure rise, sometimes significant, even in those with normal pressure and more in the hypertensive, albeit under drug therapy.
The mountain can cause some symptoms already from 1,300 meters, as the barometric pressure is reduced and the oxygen pressure in the air decreases. Furthermore, humidity and temperature are reduced. If you are not in optimal physical condition, or in older people, you may notice important changes for the first few days such as insomnia, increased blood pressure, some arrhythmias, a rapid heartbeat, shorter and heavier breath and in some cases, headache. The higher you climb these symptoms can become important. Normally, the body adapts to function in the new environment, but for people of a certain age or who have health problems such as pre-existing heart or respiratory diseases, greater caution is required. This is also the case for those who have contracted Covid -19, especially if they have developed lung disease.
An elderly person with cardiovascular problems may need a few days of adaptation at a certain height. In particular, hypertensive people with insufficient blood pressure control may experience a further increase in pressure values at altitude. In this case, it will be advisable for your doctor to verify the stability of the clinical condition and the adequacy of the current therapy.
With increasing altitude, the decreased concentration of oxygen in the air results in a strong stimulus on the sympathetic nervous system and an increased release of norepinephrine at the level of the arterioles, the small arterial vessels that regulate blood pressure. In all subjects, varying the height, there is a progressive increase in blood pressure which increases with age and also affects hypertensive patients on drug therapy.
The partial pressure of oxygen in the air goes from about 160 mm Hg at sea level to about 110 mm Hg at 3,000 meters, bringing the oxygen saturation in the blood from 98% to 90%.
On Mont Blanc (4,807 meters), the partial pressure of oxygen is reduced by 50% compared to that present at sea level. At altitudes between 5,000 and 6,000 meters, the partial pressure of O2 drops to 80 mm Hg and at the top of the highest peak in the world, Mount Everest at 8848 meters, the ppO2 is less than a third (at about 50 mm Hg ) compared to that present at sea level and the oxygen saturation drops to 25%.
The progressive reduction of atmospheric pressure and therefore of the partial pressure of oxygen induces the body to implement a series of compensatory mechanisms to adapt to the consequent tissue hypoxia (lack of oxygen in the tissues), a process that takes the name of acclimatization.
A recent research by the Italian Auxological Institute signed by Professor Gianfranco Parati, together with the University of Milano-Bicocca, published on International Journal of Cardiology, highlighted that acute exposure around 2,000 meters leads to an increase in systolic and diastolic pressure, but also to sleep disturbances, especially in males over 40. It was already known that acute exposure at high altitudes above 2,500 meters causes an increase in pressure and the appearance of central sleep apnea and periodic breathing in sleep, even in healthy subjects.
ALTITUDE CLASSIFICATIONS,
(Bartsch 2008)
Sea level 0 – 500 meters above sea level
Low Altitude 500 – 2000 meters above sea level
Average altitude 2000 – 3000 meters above sea level
High Altitude 3000 – 5500 meters above sea level
Extreme altitude> 5500 meters above sea level