# Exercise as it relates to Disease/Metabolic syndrome and trekking at altitude
## Trekking at altitude and metabolic syndrome

https://commons.wikimedia.org/wiki/File:Trekking_pic.jpg
With increased tourism to areas such as the Himalayas, the Andes and other mountain ranges of high altitude, it is important to be aware of the potential risk factors for people with metabolic syndrome so these individuals can properly prepare for the exposure to high altitude hypoxia. Metabolic syndrome definition does change around the world, however the International Diabetes Federation released a paper in 2006 detailing all descriptions around the world and found the main considerations to be someone with hypertension, dyslipidaemia, diabetes or pre-diabetes and central obesity . These four factors are examined below to guide sufferers of metabolic syndrome to the potential risks or benefits of trekking at altitude and offers some recommendations.

## Hypertension

The effects of altitude on blood pressure are variable between individuals and dependent on Altitude. For the majority of people blood pressure raises proportional to elevation gain, and is not usually significant until above 3000m.

##### Potential risks

* There is initial hypertension, followed by gradual normalization.
* Needs to be monitored as individuals have shown large increases in B/P.

##### Potential benefits

* Possible reduction in B/P with prolonged stay at altitude though evidence varies.

##### Recommendations

* Despite these risks, well-controlled hypertension is not a contraindication to high altitude travel or physical activity performed at altitude.
* To allow for the possible increase in the first few days exposure to altitude, adequate time should be taken to acclimatize properly. Some research has shown improvement after just 2 days, however the longer the exposure the better the acclimatization.

## Obesity
##### Potential risks

* Increased risk of Sleep Apnoea, which increases risk of High Altitude Pulmonary Edema.
* Obesity is positively linked with AMS.
* The secretion of a number of inflammation-related adipokines is upregulated by hypoxia, and there is a switch from oxidative metabolism to anaerobic glycolysis. Glucose utilization is increased in hypoxic adipocytes with corresponding increases in lactate production.

##### Recommendations

* Try to reduce obesity as much as possible before attempting mountain trekking to high altitude to avoid possible complications.

## Diabetes

Altitude exposure, including intensive exercise, is not contraindicated for diabetics with good glycaemic control and without vascular complications.

##### Potential risks

* Dexamethasone, the most common drug taken on expedition for Acute Mountain Sickness rapidly increases insulin resistance.
* With increasing altitude, diabetic mountaineers report a reduction in blood glucose control.
* The combined effects of elevation, temperature, and humidity can render some blood glucose monitors unreliable at moderate to high altitude.
* Early recognition of poor glycaemic control is difficult at altitude, as symptoms of hypoglycaemia are similar and may be confused with Acute Mountain Sickness.
* Potential loss of appetite seen at altitude. Diligence needed from diabetics to maintain optimal blood glucose levels.

##### Potential benefits

* Significant positive influences have been seen after time at altitude including exercise for improved insulin resistance.

##### Recommendations

* To have maximal blood glucose control, precise tracking of energy intake and expenditure, frequent blood glucose monitoring, and flexible insulin dosing are advised.

## Dyslipidaemia

No contraindications were found for patients with dyslipidaemia, only potential benefits.

##### Potential benefits

* Lower LDL levels seen after trekking and spending time at altitude.
* High density lipoprotein cholesterol levels are linearly and significantly increased when living at a higher altitude.
* Lower risk of atherosclerosis and reduced risk of coronary heart disease.
* Significant increase in HDL cholesterol.

##### Recommendations

* Spending time at altitude may enhance control of dyslipidaemia by lowering LDL and increasing HDL.

## General considerations
##### Potential risks

* The risk factors increase with increasing altitude.
* There is evidence to suggest raised risk for AMS for those with metabolic syndrome.
* Heart rate will be higher at altitude for a given intensity, which must be considered regarding exercise intensity for those with metabolic syndrome.

##### Potential benefits

* Some researchers have suggested that high altitude living conditions and activities may possibly be developed as potential natural medicines for the prevention and treatment of type II diabetes and metabolic syndrome.

## References

* ↑ Alberti, K. G. M. M., Zimmet, P., & Shaw, J. (2006). "Metabolic syndrome—a new world‐wide definition.A Consensus Statement from the International Diabetes Federation". Diabetic Medicine, 23(5), 469-480. {{cite web}}: |access-date= requires |url= (help); Missing or empty |url= (help); Text "International Diabetes Federation" ignored (help); Text "http://onlinelibrary.wiley.com/doi/10.1111/j.1464-5491.2006.01858.x/full" ignored (help)CS1 maint: multiple names: authors list (link)
* 1 2 3 Hanna, J. M. (1999). Climate, altitude, and blood pressure. Human biology, 553-582
* 1 2 3 4 5 6 7 Mieske, K., Flaherty, G., & O'Brien, T. (2010). Journeys to high altitude—risks and recommendations for travelers with preexisting medical conditions. Journal of travel medicine, 17(1), 48-62
* ↑ Rimoldi, S. F., Sartori, C., Seiler, C., Delacrétaz, E., Mattle, H. P., Scherrer, U., & Allemann, Y. (2010). High-altitude exposure in patients with cardiovascular disease: risk assessment and practical recommendations. Progress in cardiovascular diseases, 52(6), 512-524.
* ↑ Palmer, S. K., Moore, L. G., Young, D. A., Cregger, B., Berman, J. C., & Zamudio, S. (1999). Altered blood pressure course during normal pregnancy and increased preeclampsia at high altitude (3100 meters) in Colorado.American journal of obstetrics and gynecology, 180(5), 1161-1168
* 1 2 Fiori, G. G., Facchini, F. F., Pettener, D. D., Rimondi, A. A., Battistini, N. N., & Bedogni, G. G. (2000). Relationships between blood pressure, anthropometric characteristics and blood lipids in high- and low-altitude populations from Central Asia. Annals Of Human Biology, 27(1), 19-28
* ↑ Rahn, H., & Otis, A. B. (1949). Man's respiratory response during and after acclimatization to high altitude. American Journal of Physiology--Legacy Content, 157(3), 445-462
* ↑ Muza, S. R., Beidleman, B. A., & Fulco, C. S. (2010). Altitude preexposure recommendations for inducing acclimatization. High Altitude Medicine & Biology, 11(2), 87-92
* 1 2 3 Ri-Li, G., Chase, P. J., Witkowski, S., Wyrick, B. L., Stone, J. A., Levine, B. D., & Babb, T. G. (2003). Obesity: associations with acute mountain sickness.Annals of internal medicine, 139(4), 253-257
* 1 2 Strapazzon, G., Cogo, A., & Semplicini, A. (2008). Acute mountain sickness in a subject with metabolic syndrome at high altitude. High altitude medicine & biology, 9(3), 245-248
* ↑ Trayhurn, P. (2013). Hypoxia and adipose tissue function and dysfunction in obesity. Physiological reviews, 93(1), 1-21
* ↑ Wood, I. S., de Heredia, F. P., Wang, B., & Trayhurn, P. (2009). Cellular hypoxia and adipose tissue dysfunction in obesity. Proc Nutr Soc, 68(4), 370-377
* ↑ Sakoda, H., Ogihara, T., Anai, M., Funaki, M., Inukai, K., Katagiri, H., ... & Asano, T. (2000). Dexamethasone-induced insulin resistance in 3T3-L1 adipocytes is due to inhibition of glucose transport rather than insulin signal transduction. Diabetes, 49(10), 1700-1708
* ↑ Fink, K. S., Christensen, D. B., & Ellsworth, A. (2002). Effect of high altitude on blood glucose meter performance. Diabetes technology & therapeutics, 4(5), 627-635
* ↑ Litch, J. A. (1996). Drug-induced hypoglycemia presenting as acute mountain sickness, after mistaking acetohexamide for acetazolamide. Wilderness & environmental medicine, 7(3), 232-235
* ↑ Barnholt, K. E., Hoffman, A. R., Rock, P. B., Muza, S. R., Fulco, C. S., Braun, B., ... & Friedlander, A. L. (2006). Endocrine responses to acute and chronic high-altitude exposure (4,300 meters): modulating effects of caloric restriction.American Journal of Physiology-Endocrinology and Metabolism, 290(6), E1078-E1088
* ↑ Boyer, S. J., & Blume, F. D. (1984). Weight loss and changes in body composition at high altitude. Journal of Applied Physiology, 57(5), 1580-1585
* 1 2 Lee, W. C., Chen, J. J., Ho, H. Y., Hou, C. W., Liang, M. P., Shen, Y. W., & Kuo, C. H. (2003). Short-term altitude mountain living improves glycemic control. High altitude medicine & biology, 4(1), 81-91
* ↑ Coello, S. D., De León, A. C., Ojeda, F. B., Méndez, L. P., González, L. D., & Aguirre-Jaime, A. J. (2000). High density lipoprotein cholesterol increases with living altitude. International journal of epidemiology, 29(1), 65-70
* ↑ Ferezou, J., Richalet, J. P., Coste, T., & Rathat, C. (1988). Changes in plasma lipids and lipoprotein cholesterol during a high altitude mountaineering expedition (4800 m). European journal of applied physiology and occupational physiology, 57(6), 740-745
* ↑ Stenberg, J., Ekblom, B., & Messin, R. (1966). Hemodynamic response to work at simulated altitude, 4,000 m. Journal of Applied Physiology, 21(5), 1589-1594.