Do we weigh less in the mountains than at sea level? The answer is yes, even if the reduction is insignificant after all (we are talking about very few grams).
In fact, the force of gravity that attracts the body towards the center of the Earth varies with latitude (at the poles we weigh less than at the equator), but also with altitude, since in both cases the distance from the center of the Earth increases. Land. It is also necessary to consider the density of the air, which decreases significantly in the high ground together with the pressure exerted on the organism. Although this characteristic does not directly affect the weight, the "buoyancy" of the body decreases, which in turn affects the weighing process (each body immersed in a fluid receives a vertical thrust from the bottom upwards, equal in intensity to the weight of the volume of the displaced fluid, which in this case decreases). Despite this, athletic performance can increase in altitude due to the reduced air density, which creates less friction as the body advances (cycling and speed sports); on the other hand, in disciplines where air friction is less important, performance tends to decrease due to the drop in the partial pressure of oxygen, and therefore in VO2max.