Search

OBJECTIVE--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. RESEARCH DESIGN AND METHODS--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 in) 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. RESULTS--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), CONCLUSIONS--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. [ABSTRACT FROM AUTHOR]

Background: Due to increasing numbers of people with diabetes taking part in extreme sports (e.g., high-altitude trekking), reliable handheld blood glucose meters (BGMs) are necessary. Accurate blood glucose measurement under extreme conditions is paramount for safe recreation at altitude. Prior studies reported bias in blood glucose measurements using different BGMs at high altitude. We hypothesized that glucose-oxidase based BGMs are more influenced by the lower atmospheric oxygen pressure at altitude than glucose dehydrogenase based BGMs. Methodology/Principal Findings: Glucose measurements at simulated altitude of nine BGMs (six glucose dehydrogenase and three glucose oxidase BGMs) were compared to glucose measurement on a similar BGM at sea level and to a laboratory glucose reference method. Venous blood samples of four different glucose levels were used. Moreover, two glucose oxidase and two glucose dehydrogenase based BGMs were evaluated at different altitudes on Mount Kilimanjaro. Accuracy criteria were set at a bias <15% from reference glucose (when >6.5 mmol/L) and <1 mmol/L from reference glucose (when <6.5 mmol/L). No significant difference was observed between measurements at simulated altitude and sea level for either glucose oxidase based BGMs or glucose dehydrogenase based BGMs as a group phenomenon. Two GDH based BGMs did not meet set performance criteria. Most BGMs are generally overestimating true glucose concentration at high altitude. Conclusion: At simulated high altitude all tested BGMs, including glucose oxidase based BGMs, did not show influence of low atmospheric oxygen pressure. All BGMs, except for two GDH based BGMs, performed within predefined criteria. At true high altitude one GDH based BGM had best precision and accuracy. [ABSTRACT FROM AUTHOR]

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, 4,167m), 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 ± 0.3W/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. [ABSTRACT FROM AUTHOR]