Article

Increased Insulin Requirements During Exercise at Very High Altitude in Type 1 Diabetes

Department of Internal Medicine, Canisius Wilhelmina Hospital, Nijmegen, the Netherlands.
Diabetes care (Impact Factor: 8.42). 02/2011; 34(3):591-5. DOI: 10.2337/dc10-2015
Source: PubMed

ABSTRACT

Safe, very high altitude trekking in subjects with type 1 diabetes requires understanding of glucose regulation at high altitude. We investigated insulin requirements, energy expenditure, and glucose levels at very high altitude in relation to acute mountain sickness (AMS) symptoms in individuals with type 1 diabetes.
Eight individuals with complication-free type 1 diabetes took part in a 14-day expedition to Mount Meru (4,562 m) and Mount Kilimanjaro (5,895 m) in Tanzania. Daily insulin doses, glucose levels, energy expenditure, and AMS symptoms were determined. Also, energy expenditure and AMS symptoms were compared with a healthy control group.
We found a positive relation between AMS symptoms and insulin requirements (r = 0.78; P = 0.041) and AMS symptoms and glucose levels (r = 0.86; P = 0.014) for Mount Kilimanjaro. Compared with sea level, insulin doses tended to decrease by 14.2% (19.7) (median [interquartile range]) (P = 0.41), whereas glucose levels remained stable up to 5,000 m altitude. However, at altitudes >5,000 m, insulin dose was unchanged (36.8 ± 17 vs. 37.6 ± 19.1 international units [mean ± SD] P = 0.75), but glucose levels (7.5 ± 0.6 vs. 9.5 ± 0.8 mmol/L [mean ± SD] P = 0.067) and AMS scores (1.3 ± 1.6 vs. 4.4 ± 4 points [mean ± SD] P = 0.091) tended to increase. Energy expenditure and AMS symptoms were comparable in both groups (P = 0.84).
Our data indicate that in complication-free individuals with type 1 diabetes, insulin requirements tend to increase during altitudes above 5,000 m despite high energy expenditure. This change may be explained, at least partly, by AMS.

Full-text

Available from: Henk J G Bilo
Increased Insulin Requirements During
Exercise at Very High Altitude in
Type 1 Diabetes
PIETER DE MOL, MD
1,2
SUZANNA T. DE VRIES, MD
3
EELCO J.P. DE KONING, MD, PHD
4,5
RIJK O.B. GANS, MD, PHD
6
CEES J. TACK, MD, PHD
2
HENK J.G. BILO, MD, PHD
6,7
OBJECTIVE Safe, very high altitude trekking in subjects w ith type 1 diabetes req uires un-
ders tanding of glucose regulation at high altitude. We investigated insulin requirements, energ y
expenditure, and glucose le vels at very high altitude in relation to acute mountain s ickness (AMS)
symptoms in individuals with type 1 diabetes.
RESEARCH DESIG N AND METHODSEight ind ividuals with complication-free type
1 diabetes took part in a 14-day expedition to Mount Meru (4,562 m) and Mount Kilimanjaro
(5,895 m) in Tanzania. Dail y insulin doses, glucose levels, energy expenditu re, and AMS symp-
toms were dete rmined. Also, energy expenditure and AMS symptoms were compared with a
healthy control group.
RESULTSWe found a positive relation between AMS symptoms and insulin requirements
(r = 0.78; P = 0.041) and AMS symptoms and glucose levels (r =0.86;P = 0.014) for Mount
Kilim anjaro. Compared with sea level, insulin doses tended to decrease by 14.2% (19.7) (median
[interquartile range ]) (P = 0.41), whereas glucose levels remained stable up to 5,000 m altitude.
However, at altitudes .5,000 m, insulin dose was unchanged (36.8 6 17 vs. 37.6 6 19.1
international units [mean 6 SD] P = 0.75), but glucose levels (7.5 6 0.6 vs. 9.5 6 0.8 mmol/L
[mean 6 SD] P = 0.067) and AMS scores (1.3 6 1.6 vs. 4.4 6 4points[mean6 SD] P =0.091)
tended to increase. Energy expenditure and AMS symptoms were comparable in both groups (P =
0.84).
CONCLUSIONS Our data indicate that in complic ation-free individuals with type 1 di-
abetes, insulin requirements tend to increase during altitudes above 5,000 m despite high energy
expenditure. Thi s change may be explained, at lea st partly, by AMS .
Diabetes Care 34:591 595, 2011
A
n increasing number of people with
type 1 diabetes participate in ex-
trem e physical activity, such as v ery
high altitude tre kking, dened as trek-
king at altitudes between 3,5 00 and 5,50 0
m (11,50018,000 ft) (1). Very high alti-
tude trekking poses specic demands on
indi viduals with type 1 diabete s, because
many physiologic processes, including
glucose metabolism, energy expenditure,
and insulin requirements, differ at altitude
compared with sea level (2).
In individuals without diabetes, exer-
cise at altitude initial ly elicits an increas e
in both glucose and insulin. However,
after 3 weeks at 4,300 m, resting gluco se
levels and glucose levels during exercise
decrease compared with sea level values,
whereas insulin levels return to and remain
at sea level values. This suggests decreased
glucose mobilization or increased insulin
sensitivity as a result of acclimatization to
high altitude (3,4).
In individuals with type 1 diabetes,
the increase in glucose uptake by skel etal
muscle in response to aerobic exercise at
sea level is comparable to that in subjects
without diabetes (5). However, because
individuals with type 1 diabetes, by deni-
tion, lack the ability to automatically adjust
insulin levels and have defective counter-
regulatory mechanisms (6), the initial re-
sponse to exercise at high altitude will be
different from that of healthy individuals.
Furthermore, all individuals at very
high altitud e are at risk for developing
acute mountain sickness (AMS), which,
in its early stages, is characterized by
headache, depressed appetite, gastroin-
testinal symptoms, fatigue, and sleeping
problems. AMS is accompanied by in-
crea sed sympathetic activ ity and an in-
crease in plasma c atecholamines that
could result in a deterioration of glycemic
control (7).
It is difcult to predict individual in-
sulin requirements and glucose proles in
response to exercise at very high altitude in
individuals with type 1 diabetes. In addi-
tion, AMS may deteriorate glycemic control.
These factors could therefore compro-
mise safe trekking at very high altitude .
To our knowledge, no study has yet
assessed a possible relationship between
the occurrence of AMS and hyperglycemia
in type 1 diabetes. Furthermore, whether
insulin requirements increase or decrease
in response to very high altitude in type 1
diabetes remains subject to debate (810).
Therefore, in this study, we deter-
mined daily insulin doses and glucose
levels in subjects with type 1 diabetes at
very hi gh altitude. Furthermore, we com-
pared daily energy expenditure and AMS
symptoms in subjects with type 1 diabetes
with those of a healthy control group.
RESEARCH DESIGN AND
METHODS
Subjects
Eight patients with complication-free
type 1 diabetes were recru ited by adver-
tisement and selected to take part in the
ccccccccccccccccccccccccccccccccccccccccccccccccc
From the
1
Department of Internal Medicine, Canisius Wilhelmina Hospital, Nijmegen, the Netherlands;
the
2
Department of Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, the
Netherlands; the
3
Department of Cardiology, Tjongerschans Hospital, Heerenveen, the Netherlands; the
4
Department of Nephrology, Leiden University Medical Centre, Leiden, the Netherlands; the
5
Department
of Endocrinology, Leiden University Medical Centre, Leiden, the Netherlands; the
6
Department of Internal
Medicine, University Medical Centre, Groningen, the Netherlands; and the
7
Department of Internal
Medicine, Isala Clinics, Zwolle, the Netherlands.
Corresponding author: Pieter de Mol, p.demol@aig.umcn.nl.
Received 25 October 2010 and accepted 21 December 2010.
DOI: 10.2337/dc10-2015
© 2011 by the American Diabetes Association. Readers may use this article as long as the work is properly
cited, the use is educational and not for prot, and the wor k is not altered. See http:// creativecommons.org/
licenses/by-nc-nd/3.0 / for details.
care. diabetesjournals.org DIABETES CARE, VOLUME 34, MAR CH 2011 591
Clinical Care/Education/Nutrition/Psychosocial Research
ORIGINAL ARTICLE
Page 1
Bas va n de Goor Foundation Kilimanjaro
Challenge (11). Nonmedical criteria for
selection were personal motivation and
willingness to function in a team.
Medical exclusion criteria were the
presence of complications (retinopathy,
neuropathy, nephropathy), uncontrolled
hypertension (systolic blood pressure
.150 mmHg or diastolic blood pressure
.90 mmHg), severe hypoglycemia un-
awareness, cardiac disease (abnormal
electrocardiogram, impla ntable cardio-
verter debrillator or pacemaker, cardio-
myopathy, coronary or clinically relevant
valvular disease), peripheral arterial in-
sufciency, and smoking or use of illici t
drugs.
The contro l grou p consisted of nine
individuals without diabetes (four MDs,
one clini cal chemist, one laboratory tech-
nician, one echocardiographer, and two
research assistants), and all were subjected
to the same criteria and training program as
the type 1 diabetes group.
Before the expedition, all participants
underwent a physical examination, max-
imal exertion cycle ergometer testing,
electrocardiography, echocardiogra phy,
and laboratory testing, and were given
general training advice. The research pro-
tocol was appro ved by the local ethics
committee of the Isala Clinics, Zwolle, the
Netherlands, and all subjects gave writte n
info rmed consent.
Itinerary
After arrival in Arusha, Tanzania (altitude
1,254 m), a 3-day ascent of Mount Meru
(altitude 4,568 m) was made to facilitate
acclimatization to altitude. Subsequently,
all subje cts remained at 1,254 m altitude
for 1 day and continued for the 7-day
ascent of Mount Kilimanjaro (altitude
5,895 m), taking the Machame route (12).
Measurements
Daily insulin dosages were recor ded fro m
subcutan eous insu lin pumps (MiniMed
Paradigm MMT 770, Medtronic Inc.,
Minneapolis, MN [n = 6] and Accu Chek
Spirit, Roche Diagnostics, Basel, Swit zer-
land [n = 1]) and manual recording by one
subject using a four times daily insulin
injection regimen. All subjects with dia-
betes regulated their own glucose levels
and, in principl e, determined their own
insulin doses. Daily glucose levels were
recorded by the diabetes group using
a continuous glucose monitoring (CGM)
system (MiniMed Paradigm Real Time,
Medtronic Inc.) and handheld blood glu-
cose meters (BGMs) (Accu Chek Compact
Plus, Roche Diagnostics). The BGMs used
were successfully tested for accuracy at
very high altitude (5,000 m) as previously
reported (13) and tested regularly at dif-
ferent altitu des using stand ard reference
glucose solutions (NOVA Biomedical,
Waltham, MA). Per subject, per day, a to-
tal of 17 h 42 min 6 1 h 12 min data of
CGM were available for analysis (mean 6
SD). CGM calibrations with handheld
BGMs were performed four (six) times
daily (median [interquartile range, IQR]).
Energy expenditu re was monitored in
all subjects using a right upper armband
estimating energy expenditure from var-
ious physiologic and movement parame-
ters monitored (SenseWear Pro Armband,
Bodymedia, Pittsburgh, PA).
AMS score was recorded daily in all
subjects according to t he Lake Louise
Score. This score is composed o f ve
items graded from 0 (not present) to 3
(severe): headache, gastrointestinal symp-
toms, dizziness or light headedness, dif-
culty sleeping, and fatigue or weakness. A
diagnosis of AMS is based on the presence
of headache, at least one other symptom,
and a total score of $4 (14).
Statistical analysis
Differences between two means were
tested by Student t tests for data with nor-
mal distribution. Mean glucose was calcu-
lated by area under the curve analysis
from CGM data. Also, the time subjects
spent in hyper- and hypoglycemia, de-
ned as episodes with glucose levels
.
10 mmol/L and ,3.5 mmol/L, respec-
tively, was calculated by CGM data anal-
ysis. Correlations were calculated using
Spearman r analyses for data that were
not normally distributed. For comparisons
between groups in time, mixed repeated-
measures ANOVA was used for data that
were normally distributed.
The SPSS personal software package
(version 16.0; SPSS Inc., Chicago, IL) was
used for statistical analysis. A P value of
, 0 .05 was considered statistically signif-
icant. Data are presented as means 6 SD
unless stated otherwise.
RESULTS
Subjects
Base line charac teristics of al l tested sub-
jects are listed in Table 1. Apart from
younger age and HbA
1c
levels, partici-
pants with diabetes were comparable to
the control group.
During the ascent of Mount Meru,
two subjects of the diabetes group did not
reac h the summit because of viral gastro-
enteriti s in one and AMS in the other. One
subject reached camp two at 3,580 m
altitude, a nd one subject returned to
camp one at 2,514 m altitude. These
subjects were still includ ed in the analy-
sis, because both eventu ally reached the
summit of Mount Kilimanjaro.
During the climb of Mount Kiliman-
jaro, all participants with type 1 diabetes
reac hed the summit without major prob-
lems. One subject from the nondiabetes
group stayed at base camp because of
knee problems, after successfully sum-
miting mount M eru. The altitude prole
of the expedition is presented in Fig. 1
(shaded area).
Insulin doses
Daily insu lin doses are depicted in Fig. 1
(top). During the ascents of both mount
Meru and m ount Kilimanjaro, mean insu-
lin dose decreased nonsignicantly with a
subsequ ent return to baseline values on
resting days (P = 0.84). Although there
was substantial interind ividual variation,
the insulin dose was reduc ed, albeit not
signicantly: 214.2 6 19.2% (median 6
IQR) (P = 0.41) (Fig. 2). When analyzed
over the whole expedition period, insulin
dose tended to be lower at higher altitudes
(r = 2 0.51, P =0.054).
Table 1Baseline characteristics of study participants
Type 1 dia betes Control participants
N (male/female) 8 (5/3) 9 (4/5)
Age (years) 31.6 6 5. 3 42.1 6 9.9*
HbA
1c
(%) 6.8 6 0.6 5.2 6 0.4*
Diabetes duration (years) 10.4 6 8.1 n.a.
Blood pressure (mmHg) 117/69 6 5.9/3.3 118/75 6 11.9/9.2
BMI (kg/m
2
) 23.9 6 1.9 23.7 6 1.8
Acetazolamide use (yes/no) 6/2 7/2
Data are presented 6 SD. n.a., not applicable. *P , 0.05.
592 DIABETES CARE, VOLUME 34, M ARCH 2011 care.diabetesjournals.org
Type 1 diabetes and high a ltitude
Page 2
Glucose
Mean daily gl ucos e measured by CGM is
depicted in Fig. 1 (middle). Glucose levels
tended to increase, compared with base-
line (1,254 m), d uring the ascent of
Mount Meru (P = 0.086) but remained
elevated even after the descent to 1,254 m
(P = 0.002; day 1 vs. day 6). During the
ascent of Mount Kilimanjaro, glucose lev-
els initially dec reased nonsignicantly (P =
0.079). However, glucose levels increased
steeply to their highest level on the sum-
mit day (day 1 vs. day 12, P = 0.020). We
found no relation between glucose levels
and altitude (r = 0.12, P = 0.67).
Time per day in hyperglycemia tended
to increa se on Mount Meru compared
with bas eline values (212 6 228 min [sea
level] vs. 284 6 405 min [day 3], P =
0.076), subsequently decreased nonsig-
nicantly on Mount Kilimanjaro (127 6
168 min [day 11], P = 0.47), but peaked
signican tly on the summit day (500 6
568 min [sea level vs. day 12], P =
0.041, Friedman analysis, median 6
IQR). Time per day in hypog lycemia did
not differ between sea level and any altitude
(11 6 31 vs. 0 6 54 min [median 6 IQR],
P = 0.9, Friedman analysis). None of the
subjects required help of a second party
for hypoglycemic episodes.
Acute mountain sickness
As expected, m ean AMS scores increased
in parallel with altitude in both groups (sea
level vs. 4,562 m [P=0.015] and sea level
vs. 5,895 m [P=0.019]) and were strongly
correlated; r =0.92(P = 0.0001) (Fig. 1,
bottom). There were no signicant differ-
ences in AMS scores between the diabetes
group and the control group (P =0.79).
When a nalyzing both ascents sepa-
rately for possible effects of acclimatiza-
tion, there was a strong relat ion betwe en
AMS and glucose levels for Mount Kili-
manjaro (r = 0.86; P = 0.014). Also, for
Mount Kilimanjaro, we found a positive
relation b etween insulin doses and AMS
scores (
r =0.78;P =0.041).However,
there was no relation between AMS and
glucose levels over the whole expedition
period (r = 0.15; P = 0.60).
Energy expenditure
Energy expenditure increased signi-
cantly at altitude, 3,012 6 578 (day 6)
vs. 5,044 6 937 (day 12) c al/day
(mean 6 SD) (P = 0. 0001), and followed
the same trend as the altitude prole (Fig. 3).
Energy expenditure was comparable be-
tween the diabetes group and the control
group (P =0.57).
CONCLUSIONSThis study investi-
gated the relationships among daily in-
sulin doses, glucose proles, and AMS
symptoms in res ponse to exercise at very
high altitude in subjects with complication-
free type 1 diabetes. As anticipated, in-
sulin doses initially tended to decrease
while glucose levels remained fairly stable
at altitude. However, during the nal
ascent (day 12), glucose levels increased
sharply in parallel to an increase in AMS
scores but insulin doses did not change.
Taken together, these results are in accor-
dance with an increased insulin require-
ment when extreme altitudes (.5,000 m)
are reached (day 12). On the nal ascent,
the increments in AMS symptoms and
mean glucose are borderline signicant.
However, the signicant increase in time
in hyperglycemia and the positive rela-
tions between AMS and mean glucose lev-
els, and AMS and insulin doses, support
the notion of increas ed insulin require-
ments at extreme altitude, possibly related
to AMS.
Figure 1Me an insulin dosage (black circles; top), mean glucose from CGM (black squares;
middle),andmeanAMSscoreperday(black triangles: downward: diabetes group, upwa rd:
control group; bottom) during the expedition; left Y axis. Altitude prole of expedition (gray line,
shaded area); right y-axis. Note: Altitude presented on ex pediti on days is the highest altitude
reached that specic day. AMS scores comprise seven subjects with type 1 diabetes. Data are
presented as means 6 SD.
Figure 2Relative change in daily insulin dose compared with sea level doses during the ex-
pedition (mean 6 SD; %).
care. diabetesjournals.org DIABETES CARE, VOLUME 34, MAR CH 2011 593
de Mol and Associates
Page 3
The increased gluco se levels (day 12)
cannot be attributed to an increased
carbohydrate intake, because higher an-
orexia scores on the Lake Louise Ques-
tionnaire suggested markedly reduced
caloric intake at altitudes .4,500 m
(data not shown). In addition, reduced
exercise-stimulated glucose uptake is
unli kely because energy expenditure in-
creased in response to exercise at altitude.
The fact that increments in glucose, to-
gether with unchanged insulin doses,
were accompanied by parallel incre ments
in AMS scores suggests a shared causative
factor.
Even after partial restoration of glucor-
egulatory hormone levels because of accli-
matization, ascent to higher altitudes will
elicit increments in gluco-counterregulatory
hormones (3). Furthermore, AMS in itself
is related to increments of counter reg-
ulatory hormones (7). Therefore, it seems
likely that after an initial acclimatization to
altitudes of up to 6 4,500 m, increments
in AMS and altitude on day 12, again,
induced a state of insulin resistance by in-
crements in counterregulatory hormones.
Previous expeditions with individuals
with type 1 diabetes have shown diverg-
ing results ( 810). Moore et al. (10) have
reported decrements in insulin doses on
Mount Kilimanjaro of up to 50%. This
expedition had a very low summit s uccess
rate and was complicated by case s with
keto-acidosis. This suggests insulin un-
derdosing. In our study, insulin dose
was init ially decreased by approximately
1520% (Fig. 2). However, it is likely that
above a critical altit ude of approximately
5,000 m this decreased insulin dose be-
comes inadequate as glucose levels in-
crease. A critical altitude of approximately
5,000 m might also explain why for Mount
Meru we did not nd a relation between
AMS and glucose levels.
Admettla et al. (9) fo und increased in-
sulin requirements at altitudes above
5,000 m when adjusting for carbohydrate
intake in a group of type 1 diabetic climb-
ers on Mount Aconcagua (6,962 m).
Pavan et al. (8) reported increased insulin
requirements in eight climbers with type 1
diabetes on Mount Cho Oyu (8,201 m)
and increased HbA
1c
levels in type 1 di-
abetic subjects and healthy controls after
this 39-day expedition. Thus, most reported
studies seem to be in line with the concept
that at extreme (.5,500 m) and even very
high (3,5005,000 m) altitudes, gl u cose
levels and insulin requirements increase
despite the high energy expenditure and
lower carbohydrate intake.
Our study has c linical implications.
At very high altitude, we would recom-
mend climbers with type 1 diabe tes to
maintain or only slightly decrease insulin
doses despite strenuous exercise and re-
duced calor ic intak e. Also, if more symp-
toms of AMS occur, one should expect to
see an increase in insulin requirements.
Although the use of acetazolamide is
not recommended in patients with typ e 1
diabetes b ecause of the perceived risk for
keto-acidosis (9), six of eight subjects
with diabetes in our study used the drug
without any complications.
This study has lim itations. First, we
did not monitor caloric intake because we
were not informed in advance what type
of food would be provided. Also, it was
difcult to estimate carbohydrate contents
of local foods. However, higher anorexia
scores on the Lake Louise Questionnaire
suggests markedly reduced caloric intake at
altitudes .4,500 m. Furthermore, because
of ethical and nancial constraints, it was
not feasible to use CGM devices to measure
glucose continuously in the control group.
Insulin requirements can hardly be deter-
mined in subjects without diabetes while
exercising at very high altitude. Therefore,
it was not possible to compare between
groups for insulin requirements and glucose
levels.
Second, acetazolamide, which was
used by 675% of all subjects in both
groups, could have inuenced AMS
scores and insulin doses at very high alt i-
tude. Acetazolamide helps to prevent
AMS and thus could attenuate counter-
regulatory hormonal responses associated
with high altitude and AMS. As far as we
know, this has not been investigated in
humans, so the degree of interf erence re-
mains speculative. Because of the small
number of subjects who did not use acet-
azolamide (Table 1), we could not statis-
tically analyze whether acetazolamide use
inuenced insulin requirements or not.
However, we could not discover any con-
sistent pattern between acetazolamide
users and nonusers regarding insulin re-
quirements. Finally, we were unable to
measure counterregulatory hormone lev-
els because of local lim itations of blood
sampling, handling, and stora ge.
One strength of our study is the use of
continuous measurement of ener gy ex-
penditure and glucose monitoring at very
high and extreme altitudes, which pro-
vides detailed information on glucose
tre nds and exercise intensity. Further-
more, CGM proved to function well at
very high altitudes and provides the sub-
jects with diabetes with instant access of
actual glucose levels and trends.
In summary, in individuals with type
1 d iabetes, insulin requirements tend to
increase during very high altitude tre k-
king despite high energy expenditure and
reduced caloric intake. This change may
be explained, at least partly, by AMS. The
role of AMS and counterregulatory hor-
mones warrants f urther investigation.
AcknowledgmentsThe Bas van de Goor
Foundation, the Netherlands, provided sup-
port and funding of the expedition.
No potential conicts of interest relevant to
this article were repo rted.
P.d.M. wrote study protocol , researched
data, and wrote the article. S.T.d.V. researched
data, reviewed the article, and contributed to
design/data collection. E.J.P.d.K. and R.O.B.G.
contributed to and re viewed and edited the
article and contributed to study design. C.J.T.
contributed to and re viewed and edited the
article. H.J.G.B. reviewed and ed ited the article
and c ontributed to study design.
Figure 3Energy expenditure per day of the type 1 diabetes group (black circles) and the control
group (black squares) (left y-axis) during the expedition in relation to the altitude prole (gray
line, shade d area; right y-axis). Day 6 is a day of rest in between ascents.
594 DIABETES CARE, VOLUME 34, M ARCH 2011 care.diabetesjournals.org
Type 1 diabetes and high a ltitude
Page 4
Parts of this study were presented in poster
form at the 69th Scie nticSessionsofthe
American Diabetes Association, New Orleans,
Louisiana, 59June2009.
The authors thank Snow Leo pard Travels,the
Netherlands, and local porters and guides for
expedition logistics and support. The authors
thank Medtronic Inc., Heerle n, the Nether-
lands, for providing CGM equipment and ac-
cessories. The authors thank all participants
for participation in this study.
References
1. Dietz TE. International Society for
Mountain Medicine ISMM: an altitude
tutorial [article online], 2006. Available
from http//:www.ismmed.org/np_altitude_
tutorial.html. Accessed 30 January 2011
2. Brubaker PL. Adventure travel and type 1
diabetes: the co mplicating effects of hi gh
altitude. Diabetes Care 2005;28:25632572
3. Larsen JJ, Hansen JM, Olsen NV, Galbo H,
Dela F. The effec t of alti tude hypoxia on
glucose homeostasis in men. J Physiol
1997;504:241249
4. Sawhney RC, M alhotra AS , Singh T, Rai
RM, Sinha KC. Insulin sec retion at high
altitude in man. Int J Biometeorol 198 6;
30:231238
5. Yki-Järvinen H, DeFronzo RA, Koivisto
VA. Normalization of insulin sensitivity in
type I diabeti c subjects by physical train-
ing during insulin pump therapy. Di-
abetes Care 1984;7:520527
6. Cryer PE. Mechanisms of hypoglycemia-
associated autonomic failure and its com-
ponent syndromes in diabetes. Diabetes
2005;54:35923601
7. Loeppky JA, Icenogle MV, Maes D, Riboni
K, Sco tto P, Roach RC. Body temperature,
autonomic responses, and acute moun-
tain sickness. High Alt Med Biol 2003;4:
367373
8. Pavan P, Sarto P, Merlo L, et al. Metabolic
and cardiovascular parameters in type 1
diabetes at extre me altitude. Med Sci
Sports Exerc 2004;36:12831289
9. Admettla J, Leal C, Ricart A. Diabetes and
mountain sports [article online], 2001.
Available from http://www.idea200 0.org/
moreinfo/docs/diab&mountains.pdf.
Accessed 30 January 2011
10. Moore K, Vizzard N, Coleman C,
McMahon J, Hayes R, Thompson CJ. Ex-
treme altitude mountaineering and type 1
diabetes; the Diabetes Federation of Ire-
land Kilimanjaro Expedition. Diabet Med
2001;18:749755
11. Bas van de Goor Foundation Kilimanjaro
Challenge 2008 [article online], 2 008.
Available from http://www.kc2008.org/.
Accessed 30 January 2011
12. Machame route [article online], 2010.
Available from http://www.uhurupeak.
com/c ategory/machame-route/. Accessed
30 January 2011
13. de Mol P, Krabbe HG, de Vries ST, et al.
Accuracy of ha ndheld blood glucose me-
ters at high altitude. PLoS ONE 2010;5:
e15485
14. Maggiorini M, ller A, Hofstetter D,
Bärtsch P, Oelz O. Assessment of acute
mountain sickness by different score pro-
tocols in the Swiss Alps. Aviat Space Envi-
ron Med 1998;69:11861192
care. diabetesjournals.org DIABETES CARE, VOLUME 34, MAR CH 2011 595
de Mol and Associates
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    • "As described by literature, type 1 diabetics can participate in extreme altitude mountaineering. However there are significant risks associated with such activity, including hypoglycemia, ketoacidosis, retinal haemorrhage [4] and proteinuria [5], with the additional difficulties in assessing glycemic control due to meter inaccuracy at high altitude [6]. The prevalence of acute kidney injury (AKI) at high altitude is presently unknown, especially in T1D subjects. "
    [Show abstract] [Hide abstract] ABSTRACT: Introduction and Aims: Medical problems occur at high altitude. The classical physiological responses to high altitude include hyperventilation, polycythemia and hypoxiemia. Type 1 diabetes (T1D) can participate in extreme altitude mountaineering. The prevalence of acute kidney injury (AKI) at high altitude is not known. We studied the renal function, by urinary Neutrophil gelatinase-associated lipocalin (uNGAL) in high altitude, as a promising biomarker for early detection of AKI. Methods: The 2012 ADIQ Expedition team included 4 male Caucasians participants (prt): two with T1D and two non-diabetics. Urine Glucose, Protein, Urobilinogen, pH, Specific Gravity, Blood, Ketones, Nitrite and Leucocytes were determinated on-site by Aution Sticks. The uCreatinine and uUrea were measured by F360 analyzer. uNGAL concentration was measured by the ARCHITECT urine NGAL assay. Microalbumin concentration was obtained by Beckman Image. Urine Total Protein measured by Dimension Vista analyser. The data has been normalized for urinary creatinine. Results: All expedition prt collected the urine samples (5000, 5600 m). The urinary qualitative results by dipstick evaluation showed normal values in all cases. The values of glycaemia in T1D prt were high after arrival at basecamp (without presence of ketones). The uNGAL concentrations and uNGAL/uCrea ratios were also lower than 132 ng/ml (cut-off of uNGAL) in all participants. Conclusions: All the prt had normal uNGAL during the time of expedition, suggesting normal renal activity also confirmed by the analysis of the other parameters. The renal function in T1D prt was preserved despite the abnormal metabolic state represented by hyperglycemia. In this type of activity, level of training is especially important.
    Full-text · Article · Jan 2014 · Journal of Diabetes & Metabolism
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    • "Kilimanjaro (5,895 m). Our observations on the impact of high altitude trekking on metabolic control have been reported elsewhere [14]. "
    Preview · Article · Jan 2014
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    • "Exposure to high altitude can initially lead to higher levels of insulin, glucose, and counter-regulatory hormones, possibly related to AMS (9–11), which typically occurs at altitudes above 3,000 m (12,13). In our study, mean glucose and time in hyper- and hypoglycemia remained stable, consistent with absent glycemic deregulation at altitude. "
    [Show abstract] [Hide abstract] ABSTRACT: OBJECTIVE Limited information is available regarding the metabolic effects of high altitude trekking in patients with type 2 diabetes. RESEARCH DESIGN AND METHODS Thirteen individuals with type 2 diabetes took part in a 12-day expedition to the summit of Mount Toubkal (altitude, 4,167 m), Morocco, after 6 months of exercise training. Energy expenditure, body weight, blood glucose, fasting insulin, lipids, and HbA1c were assessed. RESULTS Training reduced fasting glucose (−0.7 ± 0.9 mmol/L, P = 0.026) and increased exercise capacity (+0.3 ± 0.3 W/kg, P = 0.005). High altitude trekking decreased fasting insulin concentrations (−3.8 ± 3.2 μU/L, P = 0.04), total cholesterol (−0.7 ± 0.8 mmol/L, P = 0.008), and LDL cholesterol (−0.5 ± 0.6 mmol/L, P = 0.007). CONCLUSIONS High altitude trekking preceded by exercise training is feasible for patients with type 2 diabetes. It improves blood glucose, lipids, and fasting insulin concentrations, while glucose control is maintained.
    Full-text · Article · Jul 2012 · Diabetes care
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