Effects of acute exposure to moderate altitude on vascular function, metabolism and systemic inflammation.
BACKGROUND
Travel to mountain areas is popular. However, the effects of acute exposure to moderate altitude on the cardiovascular system and metabolism are largely unknown.


OBJECTIVE
To investigate the effects of acute exposure to moderate altitude on vascular function, metabolism and systemic inflammation.


METHODS
In 51 healthy male subjects with a mean (SD) age of 26.9 (9.3) years, oxygen saturation, blood pressure, heart rate, arterial stiffness, lipid profiles, low density lipoprotein (LDL) particle size, insulin resistance (HOMA-index), highly-sensitive C-reactive protein and pro-inflammatory cytokines were measured at 490 m (Zurich) and during two days at 2590 m, (Davos Jakobshorn, Switzerland) in randomized order. The largest differences in outcomes between the two altitudes are reported.


RESULTS
Mean (SD) oxygen saturation was significantly lower at 2590 m, 91.0 (2.0)%, compared to 490 m, 96.0 (1.0)%, p<0.001. Mean blood pressure (mean difference +4.8 mmHg, p<0.001) and heart rate (mean difference +3.3 bpm, p<0.001) were significantly higher at 2590 m, compared to 490 m, but this was not associated with increased arterial stiffness. At 2590 m, lipid profiles improved (median difference triglycerides -0.14 mmol/l, p=0.012, HDL +0.08 mmol/l, p<0.001, total cholesterol/HDL-ratio -0.25, p=0.001), LDL particle size increased (median difference +0.45 nm, p=0.048) and hsCRP decreased (median difference -0.18 mg/l, p=0.024) compared to 490 m. No significant change in pro-inflammatory cytokines or insulin resistance was observed upon ascent to 2590 m.


CONCLUSIONS
Short-term stay at moderate altitude is associated with increased blood pressure and heart rate likely due to augmented sympathetic activity. Exposure to moderate altitude improves the lipid profile and systemic inflammation, but seems to have no significant effect on glucose metabolism.


BACKGROUND
ClinicalTrials.gov NCT01130948.
Pulmonary Division, University Hospital Zurich, Zurich, Switzerland.
Anne-Christin
AC
Stöwhas
Tsogyal D
TD
Latshang
Christian M
CM
Lo Cascio
Sina
S
Lautwein
Katrin
K
Stadelmann
Noemi
N
Tesler
Lisa
L
Ayers
Kaspar
K
Berneis
Philipp A
PA
Gerber
Reto
R
Huber
Peter
P
Achermann
Konrad E
KE
Bloch
Malcolm
M
Kohler
D000328:Adult; D000531:Altitude; D001794:Blood Pressure; D002320:Cardiovascular Physiological Phenomena; D005947:Glucose / Q000378:metabolism; D006801:Humans; D007249:Inflammation / Q000209:etiology; D050356:Lipid Metabolism; D008297:Male; D008660:Metabolism; D010100:Oxygen / Q000378:metabolism
D005947:Glucose; D010100:Oxygen