March 19, 2013
Why you should never take Diamox while altitude training:
Each year doctors write thousands of prescriptions for Acetazolamide (Diamox) to athletes looking to try out altitude training or accelerate acclimatization for a high altitude competition.
The logic is seemingly valid: “Well Diamox has been shown to reduce altitude sickness by increasing breathing so it should help athletes perform better at high altitudes too.” Athletes don’t have time to naturally acclimatize to altitude or wish to spend hundreds of dollars renting altitude simulation equipment
Unfortunately, Diamox has been shown in placebo controlled altitude training studies to reduce V02 max, endurance, and maximal power output (Garske et al. 2003).
Ironically, understanding how Diamox reduces high altitude performance requires simply understanding how it prevents altitude sickness. Diamox allows the body to tolerate increased breathing by increasing blood acidity. It produces increased blood acidity by excreting bicarbonate, an important blood buffering agent.
In addition to buffering the acidity of blood, bicarbonate also helps stave off hydrogen ions and lactic acid build up. These two exercise byproducts are considered major contributors to exercise fatigue. Interestingly, endurance athletes actually supplement with bicarbonate (simple baking soda) because clinical studies have shown performance improvements.
Another property of Diamox that may decrease altitude performance is that it is a diuretic. Dehydration is already accelerated at high altitudes by increased respiratory and urinary water loss. Exacerbating this water loss requires athletes to drink even more water to maintain performance levels and prevent overtraining.
Believe it or not there is yet another reason to not take Diamox if you are competing at high altitude. By acidifying the blood, Diamox will significantly reduce blood EPO levels and inhibit new RBC and hemoglobin production. Athletes avoid high intensity training in the first few days of high altitude training programs because lactic acid produces the same acclimatization stinting effect. Because EPO spikes in the first 5 days of altitude exposure, Diamox should be especially avoided during this early phase.
Are there any supplements that improve acclimatization or high altitude performance?
There are a variety of sport supplements that may have special applications for improving high altitude performance and accelerating acclimatization. These include a variety of supplements that help the body retain water, improve blood oxygen detection, dilate blood vessels, reduce oxidative stress, decrease blood viscosity, and reduce inflammation.
Our next post will detail all sport supplements that can improve performance at altitude!