High altitude poses problems for mountaineers, local inhabitants, and sojourners and can also substantially affect military expeditions, as it presents an assortment of difficulties that can be exacerbated during medical evacuation, particularly in exploration, humanitarian aid during disasters and combat situations. These impacts fall under three categories: physiological, environmental, and tactical. The impact of high altitude on physiological aspects includes: (i) Altitude sickness: troops at high altitude encounter acute mountain sickness (AMS), common sicknesses such as headache, nausea, vomiting, dizziness, and fatigue. However, prophylaxis with acetazolamide and dexamethasone, followed by proper acclimatization of troops, could alleviate the symptoms of altitude sicknesses. (ii) Severe cases of altitude sickness can progress into high-altitude maladies, which include: high-altitude pulmonary edema (HAPE), high-altitude cerebral edema (HACE), thromboembolic disorders, and cold injuries like frostbite, chilblain, etc. (iii) Decreased physical performance: reduced oxygen levels impair endurance and physical stamina. Individuals may experience early fatigue and a progressive decline in physical strength. (iv) Impact on cognitive functions: decision-making, memory, and focus are three cognitive processes susceptible to compromise by hypoxia and are vital in effective military operations. On the other hand, the impact of environmental conditions on high altitudes includes extremes of weather, terrain, etc. Military expeditions can be affected due to tactical and decision-making abilities, e.g, logistics supply, high-altitude communication systems, aviation, training and acclimatization. The present chapter gives insight into overcoming the challenges of high altitude on the human system by considering the above-discussed factors that can affect military expeditions at high altitudes.