Short-term Altitude Mountain Living Improves Glycemic Control

Lee, Wen Chih; Chen, Jin Jong; Ho, H.P.; Hou, Chien-Wen; Liang, Ming Pen; Shen, Yih Wen; Kuo, Chia‐Hua

doi:10.1089/152702903321489013

Cited by 26 publications

(15 citation statements)

References 16 publications

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“…This is in contrast to a Chinese study which reported improvement of glucose tolerance as assessed by oral glucose tolerance testing (OGTT) after 3 days at 2400 m in 9 untrained subjects [3]. This discrepancy may be explained by the small sample size, the different method used to assess glucose metabolism, the different ethnicity and other differences regarding the participant characteristics in the study by Lee et al [3]. However, the lack of an effect on HOMA in our study suggests that there is no clinically important effect of acute exposure to moderate altitude on insulin resistance in healthy Caucasians.…”

Section: Discussioncontrasting

confidence: 98%

Effects of Acute Exposure to Moderate Altitude on Vascular Function, Metabolism and Systemic Inflammation

et al. 2013

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BackgroundTravel to mountain areas is popular. However, the effects of acute exposure to moderate altitude on the cardiovascular system and metabolism are largely unknown.ObjectivesTo investigate the effects of acute exposure to moderate altitude on vascular function, metabolism and systemic inflammation.MethodsIn 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.ResultsMean (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.ConclusionsShort-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.Trial RegistrationClinicalTrials.gov NCT01130948

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Section: Discussioncontrasting

confidence: 98%

Effects of Acute Exposure to Moderate Altitude on Vascular Function, Metabolism and Systemic Inflammation

et al. 2013

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“…Schobersberger et al (2003) demonstrated that a 3-week stay at an altitude of 1,700 m improved homeostatic model assessment of insulin resistance and glycemic control in response to an oral glucose load. Lee et al (2003) reported that 3 days of mountain hiking at altitude of 2,400 m significantly improved glucose tolerance in sedentary subjects. Furthermore, the same group revealed that a 25 day of hiking activity at altitude of 2,200-3,800 m improved insulin sensitivity in mildly obese populations with drug abuse history (Lee et al 2004).…”

Section: Discussionmentioning

confidence: 98%

Augmented Carbohydrate Oxidation under Moderate Hypobaric Hypoxia Equivalent to Simulated Altitude of 2500 m

Goto

Morishima

Kurobe

et al. 2015

Tohoku J. Exp. Med.

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Hypoxia itself stimulates glucose uptake mediated by a mechanism independent of insulin. However, whether moderate hypoxia causes similar metabolic effect in humans remains unclear. The present study aimed to determine glycemic regulation following glucose load at a simulated moderate altitude of 2,500 m. Eight healthy young males (mean ± standard error: 24 ± 1 years; 171.3 ± 1.6 cm; 66.9 ± 3.7 kg; 22.8 ± 1.0 kg/m 2 ) consumed 75 g of glucose solution under either hypobaric condition (560 mmHg) or normobaric condition (745 mmHg). In the hypobaric chamber, the oxygen partial pressure is proportionally reduced with a reduction of atmospheric pressure, consequently leading to the hypoxic condition. Plasma glucose and serum insulin concentrations increased significantly following glucose load in both conditions (P < 0.05). However, no significant interaction (condition × time) or main effect for condition was observed. There were no significant differences in serum glycerol, plasma epinephrine, or plasma norepinephrine concentrations between the two conditions. No significant differences between the conditions were observed in changes in V 4 O 2 or V 4 CO 2 . However, the hypobaric condition showed significantly higher respiratory exchange ratioO 2 ) at 90 and 120 min following glucose load (P < 0.05 vs. normobaric condition), suggesting that carbohydrate oxidation following glucose load was enhanced in moderate hypobaric hypoxia. In conclusion, acute exposure to moderate hypobaric hypoxia significantly augmented carbohydrate oxidation following the glucose load, without affecting glucose or insulin responses. Thus, a short-time exposure to moderate hypobaric hypoxia may be beneficial for people with impaired glucose tolerance.

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“…Earlier studies have shown that both muscle contraction and hypoxia can significantly elevate glucose permeability across plasma membranes (Cartee et al, 1991;Aslesen et al, 2001;Wright et al, 2005), implying a possibility that combining exercise and hypoxia is a good treatment method for increasing insulin sensitivity. This hypothesis was recently supported by evidence that altitude living and hiking activity significantly improves glucose tolerance (Lee et al, 2003;Schobersberger et al, 2003). However, not all literatures agree that insulin sensitivity is improved at altitude (Larsen et al, 1997).…”

Section: Introductionmentioning

confidence: 95%

“…The current finding that the EPO value was persistently elevated throughout the 25-day mountaineering program is most likely due to the prolonged hiking activity (Ͼ8 h/day), which intermittently intensifies the oxygen deficit state of the mountaineers. Previous studies have demonstrated that altitude hiking activity and short-term mountain sojourn significantly improve glucose tolerance (Lee et al, 2003;Schobersberger et al, 2003). However, not all literature agrees that insulin sensitivity is increased at altitude (Larsen et al, 1997).…”

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confidence: 98%

The Role of Dehydroepiandrosterone Levels on Physiologic Acclimatization to Chronic Mountaineering Activity

Lee

Chen

Wu³

et al. 2006

High Altitude Medicine & Biology

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Previous studies have reported that glucose tolerance can be improved by short-term altitude living and activity. However, not all literature agrees that insulin sensitivity is increased at altitude. The present study investigated the effect of a 25-day mountaineering activity on glucose tolerance and its relation to serum levels of dehydroepiandrosterone-sulfate (DHEA-S) and tumor necrosis factor-alpha (TNF-alpha) in 12 male subjects. On day 3 at altitude, we found that serum DHEAS was reduced in the subjects with initially greater DHEA-S value, whereas the subjects with initially lower DHEA-S remained unchanged. To further elucidate the role of DHEA-S in acclimatization to mountaineering activity, all subjects were then divided into lower and upper halves according to their sea-level DHEA-S concentrations: low DHEA-S (n = 6) and high DHEA-S groups (n = 6). Glucose tolerance, insulin level, and the normal physiologic responses to altitude exposure, including hematocrit, hemoglobin, erythropoietin (EPO), and cortisol were measured. We found that glucose and insulin concentrations on an oral glucose tolerance test were significantly lowered by the mountaineering activity only in the high DHEA-S group. Similarly, hematocrit and hemoglobin concentration in altitude were increased only in the high DHEA-S group. In contrast, the low DHEA-S subjects exhibited an EPO value at sea level and altitude greater than the high DHEA-S group, suggesting an EPO resistance. The findings of the study imply that DHEA-S is essential for physiologic acclimatization to mountaineering challenge.

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Short-term Altitude Mountain Living Improves Glycemic Control

Cited by 26 publications

References 16 publications

Effects of Acute Exposure to Moderate Altitude on Vascular Function, Metabolism and Systemic Inflammation

Effects of Acute Exposure to Moderate Altitude on Vascular Function, Metabolism and Systemic Inflammation

Augmented Carbohydrate Oxidation under Moderate Hypobaric Hypoxia Equivalent to Simulated Altitude of 2500 m

The Role of Dehydroepiandrosterone Levels on Physiologic Acclimatization to Chronic Mountaineering Activity

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