Ascending slowly is the best way to avoid<unk> . Avoiding strenuous activity such as skiing, hiking, etc. in the first 24 hours at high<unk>  may reduce the symptoms of AMS. Alcohol and sleeping pills are respiratory depressants, and thus slow down the acclimatization process and should be avoided. Alcohol also tends to cause dehydration and exacerbates AMS. Thus, avoiding alcohol consumption in the first 24–48 hours at a higher<unk>  is optimal. Pre-acclimatization Pre-acclimatization is when the body develops tolerance to low oxygen concentrations before ascending to an<unk> . It significantly reduces risk because less time has to be spent at<unk>  to acclimatize in the traditional way. Additionally, because less time has to be spent on the mountain, less food and supplies have to be taken up. Several commercial systems exist that use<unk>  tents, so called because they mimic<unk>  by reducing the percentage of oxygen in the air while keeping air pressure constant to the surroundings. Examples of pre-acclimation measures include remote ischaemic preconditioning, using hypobaric air breathing in order to simulate<unk> , and positive end-expiratory pressure.<unk>  acclimatization<unk>  acclimatization is the process of adjusting to decreasing oxygen levels at higher elevations, in order to avoid<unk> . Once above approximately a pressure of most climbers and high-altitude trekkers take the "climb-high, sleep-low" approach. For high-altitude climbers, a typical acclimatization regimen might be to stay a few days at a base camp, climb up to a higher camp (slowly), and then return to base camp. A subsequent climb to the higher camp then includes an overnight stay. This process is then repeated a few times, each time extending the time spent at higher<unk> s to let the body adjust to the oxygen level there, a process that involves the production of additional red blood cells. Once the climber has acclimatized to a given<unk> , the process is repeated with camps placed at progressively higher elevations. The rule of thumb is to ascend no more than per day to sleep. That is, one can climb from () to () in one day, but one should then descend back to () to sleep. This process cannot safely be rushed, and this is why climbers need to spend days (or even weeks at times) acclimatizing before attempting to climb a high peak. Simulated<unk>  equipment such as<unk>  tents provide hypoxic (reduced oxygen) air, and are designed to allow partial pre-acclimation to high<unk> , reducing the total time required on the mountain itself.<unk>  acclimatization is necessary for some people who move rapidly from lower<unk> s to higher<unk> s . Medications The drug acetazolamide (trade name Diamox) may help some people making a rapid ascent to sleeping<unk>  above , and it may also be effective if started early in the course of AMS. Acetazolamide can be taken before symptoms appear as a preventive measure at a dose of 125 mg twice daily. The Everest Base Camp Medical Centre cautions against its routine use as a substitute for a reasonable ascent schedule, except where rapid ascent is forced by flying into high<unk>  locations or due to terrain considerations. The Centre suggests a dosage of 125 mg twice daily for prophylaxis, starting from 24 hours before ascending until a few days at the highest<unk>  or on descending; with 250 mg twice daily recommended for treatment of AMS. The Centers for Disease Control and Prevention (CDC) suggest the same dose for prevention of 125 mg acetazolamide every 12 hours. Acetazolamide, a mild diuretic, works by stimulating the kidneys to secrete more bicarbonate in the urine, thereby acidifying the blood. This change in pH stimulates the respiratory center to increase the depth and frequency of respiration, thus speeding the natural acclimatization process. An undesirable side-effect of acetazolamide is a reduction in aerobic endurance performance. Other minor side effects include a tingle-sensation in hands and feet. Although a sulfonamide; acetazolamide is a non-antibiotic and has not been shown to cause life-threatening allergic cross-reactivity in those with a self-reported sulfonamide allergy. Dosage of 1000 mg/day will produce a 25% decrease in performance, on top of the reduction due to high-altitude exposure. The CDC advises that Dexamethasone be reserved for treatment of severe AMS and HACE during descents, and notes that Nifedipine may prevent HAPE. There is insufficient evidence to determine the safety of sumatriptan and if it may help prevent<unk> . Despite their popularity, antioxidant treatments have not been found to be effective medications for prevention of AMS. Interest in phosphodiesterase inhibitors such as sildenafil has been limited by the possibility that these drugs might worsen the headache of mountain sickness. A promising possible preventive for<unk>  is myo-inositol trispyrophosphate (ITPP), which increases the amount of oxygen released by hemoglobin. Prior to the onset of<unk> , ibuprofen is a suggested non-steroidal anti-inflammatory and painkiller that can help alleviate both the headache and nausea associated with AMS. It has not been studied for the prevention of cerebral edema (swelling of the brain) associated with extreme symptoms of AMS. Over-the-counter herbal supplements and traditional medicines Herbal supplements and traditional medicines are sometimes suggested to prevent high<unk>  including ginkgo biloba, R crenulata, minerals such as iron, antacids, and hormonal-based supplements such as medroxyprogesterone and erythropoietin. Medical evidence to support the effectiveness and safety of these approaches is often contradictory or lacking. Indigenous peoples of the Americas, such as the Aymaras of the Altiplano, have for centuries chewed coca leaves to try to alleviate the symptoms of mild<unk> . This therapy has not yet been proven effective in a clinical study. In Chinese and Tibetan traditional medicine, an extract of the root tissue of Radix rhodiola is often taken in order to prevent the symptoms of high<unk> , however, no clear medical studies have confirmed the effectiveness or safety of this extract. Oxygen enrichment In high-altitude conditions, oxygen enrichment can counteract the hypoxia related effects of<unk> . A small amount of supplemental oxygen reduces the equivalent<unk>  in climate-controlled rooms. At (), raising the oxygen concentration level by 5% via an oxygen concentrator and an existing ventilation system provides an effective<unk>  of (), which is more tolerable for those unaccustomed to high<unk> s. Oxygen from gas bottles or liquid containers can be applied directly via a nasal cannula or mask. Oxygen concentrators based upon pressure swing adsorption (PSA), VSA, or vacuum-pressure swing adsorption (VPSA) can be used to generate the oxygen if electricity is available. Stationary oxygen concentrators typically use PSA technology, which has performance degradations at the lower barometric pressures at high<unk> s. One way to compensate for the performance degradation is to use a concentrator with more flow capacity. There are also portable oxygen concentrators that can be used on vehicular DC power or on internal batteries, and at least one system commercially available measures and compensates for the<unk>  effect on its performance up to . The application of high-purity oxygen from one of these methods increases the partial pressure of oxygen by raising the FiO2 (fraction of inspired oxygen). Other methods Increased water intake may also help in acclimatization to replace the fluids lost through heavier breathing in the thin, dry air found at<unk> , although consuming excessive quantities ("over-hydration") has no benefits and may cause dangerous hyponatremia.
Altitude sickness
Hangover
Sweating sickness
Dehydration
Motion sickness
Fatigue
Chronic mountain sickness
Carbon monoxide poisoning