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This question in some ways is related to this question asked by JollySin.

When I did my first Himalayan trek, my guide there had told me that those with a low blood pressure (BP) are more susceptible to Acute Mountain Sickness (AMS). The logic according to him was that low BP along with high altitude will result in the blood flow to the brain reducing further and the symptoms of AMS are more likely to occur at an earlier stage in those with a low BP.

Hence, is there a scientific relationship between BP(either low or high) and AMS?

Please try to include references for the answers.

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up vote 11 down vote accepted

There is no documented scientific relationship between individual blood pressure and AMS. Furthermore, your guide appears to be completely mis-informed as to the mechanics of AMS. The most common symptom of AMS - a roaring headache - is caused by swelling of the brain as the body attempts to make up for reduced oxygen in the blood by pumping harder and faster (hence an increased heart rate). See: http://www.altitudemedicine.org/index.php/altitude-medicine/learn-about-altitude-sickness

Incidentally, high blood pressure would put one at risk for cardiac arrest, not AMS, when travelling quickly to high altitudes. See: http://www.altituderesearch.org/traveling-to-altitude/113

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The possibility of brain getting less oxygen due to low blood pressure seems possible. Why completely rubbish his claim? If thought from a common sense perspective, it looks feasible that someone with low BP might face symptoms early. I might be wrong. Pardon me if I am. – Unsung Dec 20 '13 at 17:55
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I appreciate the common sense aspect of it - I get it - but you asked if there was a scientific relationship between BP and AMS. I dispute the possibility that low blood pressure makes one more susceptible to AMS because the key factor is the oxygen saturation level in the blood, which is not related to blood pressure. – Andrew Dec 22 '13 at 23:21
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@Andrew: ...because the key factor is the oxygen saturation level in the blood, which is not related to blood pressure. This statement of yours, Do you think that Human Cardiovascular system is so simple and straight forward to understand? – WedaPashi Jan 7 '14 at 6:01
    
@unsung - Given Pulmonary Oedema is caused by the fluid leaking though the lung linings and cerebral oedema fluid into the brain, a reasonable hypothesis would be low blood pressure would reduce the risk of the most serious effects of AMS. Perhaps you are right, and the bigger headaches lower down cause people with low blood pressure to turn back sooner, making it more likely people with low blood pressure suffer mild AMS and less likely to suffer serious AMS. All these are merely hypothesis, the correct answer "There is no documented scientific evidence"..... – mattnz Apr 10 at 22:29

I would think not. AMS is caused by lower atmospheric pressure which in turn reduces the number of O2 molecules you get to breathe in. Your own personal blood pressure has nothing to do with the number of O2 molecules available to breathe.

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I have low blood pressure, 90/60 read to me just one week prior to going mountain hiking in Palm Springs California (8,500 ft. elevation). I did not experience the tiredness or lack of oxygen I thought that I would. I seemed to have the same energy as I usually have without any adverse symptoms associated to what many would complain as thinner air at that height. My thinking was that it was due to my lower blood pressure since it was explained to me that since my blood was able to efficiently carry more oxygen with less pumping from my heart, the result lower pressure was needed to supply oxygen to my cells. If the air is thinner, then my heart already pumping oxygen efficiently, would only have to pump a little harder to increase the oxygen level.

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Surely blood pressure, as opposed to just PPO2, may have an impact on AMS? Acute exposure increases blood pressure; as a result those with hypertension are warned against altitude exposure. However, acclimatised individuals generally display lower resting values due to a vasodilatory effect of hypoxia on vascular smooth muscle. If anything, hypotension may be protective in the initial stages... but maybe a hindrance after acclimatisation?

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I have low blood pressure and hypothyroidism and traveled twice to Bogota, Colombia (alt of 8,600 feet). Both times I was severely sick for three days with migraine and vomiting compared to others with normal blood pressure. There has to be some connection between low blood pressure and severe altitude sickness.

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I have somewhat low blood pressure, 106/72, and I had altitude sickness fairly quickly when traveling to Banff and Lake Louise. I thought the low pressure added to the problem because if the amount of oxygen you are breathing in, is less than normal, and your blood pressure is lower, then less oxygen is getting to your brain. Makes sense to me.Symptoms of hypoxia are similar to Altitude sickness.

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My personal experience as a female, with a lifetime of low blood pressure.

I have not done much high altitude trekking. Two times in recent memory, as an adult, and both times I noticed significant peripheral edema in hands and feet as I descended. I ascended 3000 feet the first time (that's feet, not metres, so not very high at all), and 2500 feet the second time, on day hikes.

In addition to the edema, on the second time (and maybe on the first time but I didn't understand what was happening so I may not have connected the symptoms to the hike) I had insomnia afterwards, difficulty eating/digesting food, lack of appetite, developed a cough, did not feel good at all, breathing patterns were not normal and my pulse was not regular. Symptoms continued into the next day.

I did not get a headache the second time. I don't remember the first time.

I live at sea level.

I am not surprised that my body reacts this way, having lived with low blood pressure all my life. It seems I have to keep moving to keep my blood flowing. It's the vessel walls that are too dilated and slack that cause this in my opinion and experience. There is some family history too.

I get migraines caused by vasodilation from hormone fluctuations and it is cured quickly and easily with sumatriptan, a drug which causes vasoconstriction. I noticed sumatriptan is one drug of choice in treating altitude sickness.

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Hi Yvonne and welcome to TGO. This has nothing to do with AMS which occurs from 10.000+ ft and very rarely symptoms appear also above 7.000 ft. I guess your symptoms have other reasons, maybe a lack of confidence or general discomfort with the hiking experience. – Wills Apr 10 at 18:39

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