Experience From - Karl King #1, Rich Schick #1, Karl King #2, Karl King #3 , Rich Schick #2, Kevin Kepley , Dan Baglione , Laurence Chazotte ,

Karl King #1

Diamox is a carbonic anhydrase inhibitor, so it affects CO2 balance in the body. That causes increased respiration.

Not having done much research on it, I tried it before the Mosquito marathon in Leadville ( arguably the toughest marathon in the U.S. ). It did not help, as far as I could tell. Later research turned up a study which suggested that it would not aid athletic performance at altitude, and might even compromise it.

The day after the marathon I went hiking up the Mosquito ridge without the use of Diamox and actually felt much better than the day before.

Because of its action on carbonic anhydrase, carbonated beverages taste odd when you're on the drug. On the way to Leadville, I took 2 Diamox pills on the plane an hour before landing in Denver. Lunch was in a saloon in Georgetown. The local microbrew was probably a great beer, but it tasted very strange because of the Diamox.

After going off the drug, my taste for beer returned to normal in a day.

Diamox must affect the level of plasma bicarbonate, but I could not tell any difference in other electrolyte levels. The one thing I noticed is that after three days on it I had incredible heartburn problems. Those disappeared rapidly after I stopped taking Diamox.

I'll be going to Leadville in a few weeks, and I have no desire to use Diamox.

Rich Schick #1

Diamox works by causing the body to have an excess of CO2, in response you breathe a bit faster. This is important in the prevention of altitude sickness in that people who are prone to the condition tend to hypo-ventilate at altitude. For some reason their bodies do not recognize the need to breathe faster in response to the thinner air at altitude. It seems this problem is especially evident during sleep. I agree with Karl that from a theoretical standpoint Diamox would if anything hinder athletic performance. The effect of the drug is much like exceeding your anaerobic threshold before you even take your first step.

Karl King #2

I used Diamox on my first trip to Leadville ( Mosquito Marathon ) and found:

  1. it is a mild diuretic
  2. it altered apparent taste of carbonated beverages
  3. it did not aid my athletic performance
  4. it may have helped me sleep better due to increased respiration rate
On three subsequent trips to the high country for running I've not used Diamox, and actually felt better on those trips. Diamox may be useful for some people at that or higher altitudes, but it didn't do anything for me at Leadville. What has been more effective for me was to go to high altitude ( >14,000' ) upon arrival and stay there for 4+ hours and then descend for the night ( sleeping at a lower level ). On that first day I'm short of breath and have an annoying headache, but that is relieved upon going back down ( to 7500' ) for the night.

There is considerable variation in individual response to altitude, so if you've never been above 8000' before, you might want to have some Diamox along in case you find that you have a very difficult reaction to the altitude.

I like Dana Roueche's observation that you can run at high altitude if you cut back on your expectations; it won't be like running at low altitude. On the first couple days at altitude, try some short, easy running to get a feel for it. If you cut back on your pace and relax, you'll find that you can run better than you might have expected.

Karl King #3

A doctor at an "altitude clinic" I went to commented that some people have significant trouble sleeping at altitude because their breathing pattern becomes shallow and irregular during the night. That leads to poor, fit full sleep, and distress. The increased RR from Diamox provides relief from that condition.

My personal experience was that the first time I went to the High Country in CO, I took Diamox 2 hours before getting off the plane and had no sleeping problems that night.

On the second trip there I took no Diamox and did notice some distress during the first night's sleep but not thereafter.

On the last trip there I went above 14,000' for 4+ hours the first day and had no sleep problems later that night ( at 7,500 ' ).

Rich Schick #2

Diamox can definitely help with altitude acclimatization. The down side is it can have a number of unpleasant side effects. These include tingling of fingers, toes and around the mouth, causing carbonated beverages to taste really nasty, nausea, vomiting, diarrhea and abdominal cramps. The side effects can be minimized by starting at a dose of 125 mg for the first 24 hours. Also as diuretics they will make staying properly hydrated more difficult.

Appears they allow no use of Diamox under any circumstance.

Below is the official Olympic committee explanation for the rational of banning Diamox and other diuretics.

Although diuretics, under strict medical supervision, have important therapeutic indications for the elimination of excess fluid from body tissue in certain pathological conditions and for management of high blood pressure, they are nonetheless prohibited.

Diuretics are sometimes abused by competitors for two main reasons, namely:

  1. To reduce weight quickly in sports where weight categories are involved
  2. To reduce the concentration of prohibited substances by diluting the urine.
Rapid reduction of large amounts of weight in sport cannot be justified medically. Health risks are involved in such misuse because of the potential for serious side effects.

Furthermore, deliberate attempts to reduce weight artificially in order to compete in lower weight classes or to dilute urine constitutes clear manipulations which are ethically unacceptable. Therefore, the International Olympic Committee Medical Commission and the NADP include diuretics on their respective lists of prohibited substances.

My source was http://www.olympic.org/family/ioc/medical/dope2_e.html

Kevin Kepley

Rich wrote:

"They are banned substances in competition, but have that little* above which means if prescribed for a medical indication they are legal. I believe that would cover the situation of sudden travel to high altitude."
Diamox is a glaucoma medication. I know this because I used to work for the company that sells it. It would normally be prescribed for controlling glaucoma. I don't know if docs prescribe it for altitude sickness, probably so.

Dan Baglione

Diamox is used by climbers to help prevent altitude sickness. If someone gets Acute Mountain Sickness, Diamox won't help. I have never considered using it for Leadville or Hardrock; however, most of the runners in the first Everest Marathon which starts at 17000 ft. used Diamox as we trekked up to Gorak Shep.

Laurence Chazotte

Hello Kevin Sayers, I had a look on your web site (UltRunR) which is very interesting. I just would like to give you my opinion about the use of Diamox. I find it very useful when you suffer from sickness of altitude. I have made with a group of friends the ascension of the mount Kilimandjaro (5895m). The departure is at 1500m and you go to the summit in 5 days. We have spent the last night at 4600m and everybody were becoming to have headache due to altitude. Our guide, a specialist in security, gave us Diamox for 24h and everybody felt much better and arrived to the summit. It is important to don't take it during a long period, not more than 48h. I think it very efficient to support high altitude.

Concerning what the persons said about sleeping at higher altitude, I'm sure that it is a good idea. In our case, we made the opposite, the third day we climbed at 4600m and then go down to 3900m to sleep well. The day after, we climb to 4600m and slept at this altitude and, with Diamox, we had no problem for sleeping. Furthermore, you can't restore well when you sleep at high altitude and the majority of the accidents due to altitude (edema, problem of breath) appear during the night and, as you sleep it is more dangerous because are not aware. Furthermore, the complete process to make more red blood cells requires 5-6 weeks, so you will not make red blood cells by sleeping for 4 days in altitude.