Determinants of summiting success and acute mountain sickness on Mt Kilimanjaro (5895 m).
OBJECTIVE
To determine the incidence of acute mountain sickness (AMS), the frequency of summiting success, and the factors that affect these in trekkers on Kilimanjaro, one of the world's most summitted high-altitude peaks.


METHODS
The study group comprised 312 trekkers attempting Mt Kilimanjaro summit by the Marango Route. Trekkers ascended over 4 or 5 days along a fixed ascent profile, stopping at 3 huts on ascent (2700 m, 3700 m, and 4700 m) before attempting the summit. Researchers were stationed at each hut for 16 days. Each night we measured heart rate, respiratory rate, blood pressure, oxygen saturation, and Lake Louise Score. We recorded the highest altitude that trekkers reached on the mountain.


RESULTS
Of 181 complete sets of data, 111 (61%) trekkers reached the summit, and 139 (77%) developed AMS. Physiological results were not related to summit success. The incidence of AMS and summiting success were similar in those on the 4- or 5-day route. Trekkers on the 5-day route who used acetazolamide were less likely to develop AMS and more likely to summit than were those not taking acetazolamide (P = <.05); this difference was not present with trekkers on the 4-day route.


CONCLUSIONS
The risk of developing AMS is high on Mt Kilimanjaro. Although taking an extra day to acclimatize with the use of acetazolamide did provide some protection against AMS, ideally trekkers need a more gradual route profile for climbing this mountain.
Davies
Andrew J
AJ
Manchester Altitude Research Society, University of Manchester Medical School, Manchester, UK. andrewjohndavies@doctors.org.uk
Kalson
Nicholas S
NS
Stokes
Suzy
S
Earl
Mark D
MD
Whitehead
Adam G
AG
Frost
Hannah
H
Tyrell-Marsh
Ian
I
Naylor
Jon
J
D000064:Acclimatization / Q000502:physiology*; D000086:Acetazolamide / Q000627:therapeutic use; D000208:Acute Disease; D000532:Altitude Sickness / Q000453:epidemiology / Q000517:prevention & control*; D002257:Carbonic Anhydrase Inhibitors / Q000627:therapeutic use; D006801:Humans; D007630:Kenya / Q000453:epidemiology; D012307:Risk Factors; D013997:Time Factors
D002257:Carbonic Anhydrase Inhibitors; D000086:Acetazolamide