Altitude Training | Hypoxic Training

Measuring specific, exercise-related responses can help physicians determine who may be more at risk for severe high altitude illness (SHAI), according to a study conducted by researchers in France. The researchers also found that taking acetazolamide (ACZ), a drug frequently prescribed to prevent altitude illness, can reduce some of the risk factors associated with SHAI.

The findings were published online ahead of the print edition of the American Thoracic Society’s American Journal of Respiratory and Critical Care Medicine.

The three exercise-related factors identified by the researchers include oxygen desaturation at exercise (Sae), hypoxic cardiac response at exercise (HCRe) and hypoxic ventilatory response at exercise (HVRe). Sae measures the amount of oxygen that is in the blood during exercise; HCRe measures the heart’s response to exercise in a hypoxic, or low oxygen, setting, and HVRe refers to respiratory changes (notably rapid breathing) that occur during exercise in a hypoxic setting.
The researchers measured these parameters in controlled, hypoxic conditions in a lab setting that mimicked high-altitude conditions.

“These results suggest that HCRe, HVRe and substantial decreases in Sae are independent risk factors of SHAI, and that decreases in Sae and HVRe can be used to accurately predict the risk of developing SHAI,” said Jean-Paul Richalet, MD, PhD, a professor of physiology at Université Paris 13.

“To date, this is the largest epidemiological study of subjects exposed to high altitude-related illness, who were previously evaluated for their responses to hypoxia,” he added.

The researchers collected data from 1,326 men and women who were seen prior to high-altitude excursions, which included at least 3 days above 4,000 meters with overnight sleeping above 3,500 meters. Study participants were asked to complete a questionnaire, providing information about their personal and family medical history, usual physical and mountaineering activity and other factors.

Next, study participants went through a routine hypoxic exercise test, which consisted of four, four-minute phases: rest at normal oxygen levels; rest at hypoxic levels; exercise in hypoxia; and exercise in normal levels of oxygen. During the exercise test, the researchers measured heart rate, breathing and blood oxygen levels.

Following their excursions, study participants were asked to complete a questionnaire to determine if they had experienced any symptoms of high altitude pulmonary edema (HAPE), or swelling of the lung tissue; high altitude cerebral edema (HACE), which refers to swelling of the brain tissue; or severe acute mountain sickness (AMS), which can include a variety of symptoms, including headache, nausea, fatigue and dizziness. Participants were also asked to indicate if they had used ACZ.

Among the 1,326 questionnaire respondents, 318 reported that they had experienced a severe altitude illness during their high-altitude excursion, including 105 who used ACZ and 213 who did not.

Using these results, the researchers were able to identify which factors, reported both before and during the excursions, were associated with SHAI. They were also able to determine the effect of ACZ on the development of SHAI.

“We found that among those who did not use ACZ, factors including young age, female gender, history of migraine, regular physical activity, previous history of severe altitude illness, rapid ascent, HCRe, substantial changes in Sae and HVRe were significantly associated with SHAI,” Dr. Richalet said. “Geographically, the area of Ladakh, India, was associated with a higher risk of SHAI among non-ACZ users.”

In those respondents who used ACZ preventively, young age, female gender, history of migraine, regular physical activity, HCRe, substantial changes in Sae and the Alps were no longer significantly associated with SHAI, Dr. Richalet noted, but Ladakh retained borderline significance. A history of SHAI, rapid ascent and HVRe were still associated with SHAI in those who used ACZ, but the associations were not as strong as those noted in non-ACZ users.

They also found that preventive use of ACZ resulted in a 44 percent reduction in the risk of developing SHAI.

“Although it was not double-blinded and placebo-controlled, this study confirms in a large number of subjects the efficacy of the preventive use of ACZ in high-altitude-related illness,” Dr. Richalet said. “These results indicate that preventive use of ACZ may reduce the risk of SHAI in susceptible subjects to the same level as that of non-susceptible subjects.”

The study also linked frequent physical activity to an increased risk of SHAI, a result which Dr. Richalet said supports the common belief among mountaineering experts that increasing the body’s ability to absorb oxygen during exercise is not a predictor of success in high-altitude expeditions.

“Of course, that does not mean that those who visit high altitudes should stop training before an expedition, but they should realize that intense aerobic training is not a protective factor against altitude-related disorders,” he said.

The study is the first to suggest an independent association between the geographical location of ascent and SHAI.

“When adjusted for all other risk factors, especially rate of ascent, one location – Ladakh – remained associated with a higher risk of SHAI in both ACZ and non-ACZ users,” Dr. Richalet said. “No clear explanation, linked to the climate or the difficulty of the terrain, is available, although many informal reports mention the higher risk of this location.”

Dr. Richalet said that although previous episodes of SHAI are still the best predictor of new episodes, results of the study support the use of hypoxic exercise testing, especially in individuals who are planning their first high-altitude excursions.

“Ideally, testing should be aimed both at subjects with no previous experience of high altitude, who therefore lack information about potential risk factors, and those who have experienced severe symptoms in the past, in order to determine if those episodes of SHAI were due to physiological characteristics,” he said. “And of course, during a visit to high altitude regions, it must be emphasized that the best way to avoid severe symptoms is to ascend slowly – less than 400m of altitude difference between two consecutive nights above 3000 meters during the acclimatization period.”

JOINT BASE ELMENDORF-RICHARDSON, Alaska — The nation’s F-22 fighter jets went back into service Wednesday, four months after they were grounded over pilot complaints about a lack of oxygen.

Air Force instructor pilots began flying the stealth jet fighters at six bases across the U.S. This followed a stand-down order, issued in May, and imposed over hypoxia issues reported by at least 12 pilots in the past three years. Hypoxia is when the body does not receive enough oxygen.

“It’s Day One on a road to get our F-22s back in the air and back to their full operational capability,” said Lt. Col. Derek France, 3rd Operational Group commander at Alaska’s Joint Base Elmendorf-Richardson. Forty of the 170 F-22 Raptors are stationed at the Anchorage base.

In the past four months and even before, the aircraft’s oxygen related systems have been the focus of an ongoing safety investigation, France said.

“While they never pinpointed, or have yet to pinpoint, an exact cause of these incidents, they got to a point where they felt that we could, based on risk mitigation, training of air crews and inspection of the aircraft itself, get to a point where we can safely fly again,” he said. “And so that’s the decision, we passed a safety line where senior Air Force officials said that we can go ahead and train again.”

He couldn’t provide additional information about what led to the decision.

“I can’t go into the real details,” France said after the first four Raptors raced down the runway and took off on a training run over Alaska.

“They did a thorough investigation of some of the life support systems in there and some minor modifications within the cockpit to ensure the safety of the pilot,” he said.

Air Force Chief of Staff Gen. Norton Schwartz announced the end of the stand-down order in a statement issued earlier this week.

“We now have enough insight from recent studies and investigations that a return to flight is prudent and appropriate. We’re managing the risks with our aircrews, and we’re continuing to study the F-22’s oxygen systems and collect data to improve its performance,” he said in the statement.

Each $143 million plane was thoroughly inspected before being allowed to fly and will be subject to daily inspections. Pilots will also undergo physiological testing.

The first pilots to fly are instructors, who will then train other pilots once they shake off four months of inactivity.

France said no pilots have expressed concern to him about flying the F-22s, since the investigation has yet to determine the cause for the hypoxia-like symptoms.

“I think they are all fired up and ready to fly,” he said.

France expects it to take a few months before crews are back to pre-stand-down functionality.

The F-22 Raptor was introduced in 2005, and the Air Force said it has flown more than 300 homeland security missions but none in combat.

The fleet is stationed at five other bases besides Alaska: Joint Base Pearl Harbor-Hickam, Hawaii; Joint Base Langley-Eustis, Va.; Nellis Air Force Base, Nev.; Holloman Air Force Base, N.M.; and Tyndall Air Force Base, Fla.

Acute Mountain sickness (AMS) is the term given to a number of symptoms that occur after rapid ascent to high altitude.   Severe forms may be life threatening because of pulmonary or cerebral oedema.  Mild forms of this illness can affect up to 50% of population traveling to altitudes above 12,000 - 14,000 ft.

Symptoms of headache, malaise, and decreased appetite are fairly common amongst individuals traveling to altitudes greater Than 8,000 ft, but these can occur event at lower altitudes.

The mild forms of mountain sickness can usually be treated with rest, hydration, analgesics (eg. ibuprofen), and alcohol avoidance. If you are already experiencing these symptoms do not go to higher altitudes.

Slow progressive step-acclimatisation can help minimising severity of AMS.
Individuals who have already experienced an episode of mountain sickness are at risk for future trips and should seek medical advice.

Severe forms are characterized by severe shortness of breath, cough, severe headache, confusion, or hallucinations. This may progress to coma and death. This is a medical emergency. Immediate descent to lower altitude, administration of oxygen, and medical attention are required.

A very effective method that helps  minimising the severity of mountain sickness is pre-acclimation using
hypoxicators for simulated altitude training.

Friday January 07 2011

FIONNUALA Britton has turned down an invitation to compete in tomorrow’s Great Edinburgh Cross-Country championships in favour of travelling to South Africa this week for a month’s high-altitude training.

And she is joined there by Sligo’s Mary Cullen, another Irish athlete who knows only too well the frustration of finishing fourth in the European Cross-Countries.

While Britton was heartbroken to be just outside the medals in the Algarve before Christmas, Cullen was equally frustrated by having to sit out that event after breaking her collarbone in a fall from a bicycle.

Cullen is back training now and targeting a return in time for the European Indoors in Paris in March, a competition at which she won bronze last time out.

Both women will spend most of this month in a training camp at Potchefstroom, which also includes Ireland’s European 100m hurdles silver medallist Derval O’Rourke.

National inter-county champion Joe Sweeney (DSD) and Clonliffe’s Mark Kennelly will dominate Irish interest in Edinburgh after being selected on the European team in the inaugural men’s ‘international’ 8km race.

But recent European U-23 team gold medallist Mick Mulhare, his brother Dan, Mark Christie and Stephen Scullion are all racing in the earlier men’s 4km. The ‘international’ pits Britain’s double European track champion Mo Farah against his cross-country nemesis and European captain Sergey Lebid, while America will be skippered by Galen Rupp.

Lebid and Farah have had some cracking cross-country battles in recent years, including Edinburgh in 2007 and the 2008 European Cross Countries, both won by the Ukranian.

The men’s 4km features a host of Olympic and World medallists, including big-name Kenyans Eliud Kipchoge, Asbel Kiprop and Brimin Kipruto.

Kiprop is the reigning Olympic 1,500m champion, while Kipruto holds the same title in steeplechase.

The women’s race also has a star-studded field, which includes Kenya’s current world 5,000m and 10,000m champions Vivian Cheruiyot and Linet Masai as well as two-time world junior cross-country champion Genzebe Dibaba of Ethiopia and Portugal’s European champion Jessica Augusto.

Edinburgh Cross-Country

Live, tomorrow, BBC 1, 1.30

- Cliona Foley

FULL STORY

Nishiwaki M, Kawakami R, Saito K, Tamaki H, Takekura H, Ogita F.

Graduate School of Physical Education, National Institute of Fitness and Sports in Kanoya, Kanoya, Japan.

by

Haider, Thomas; Casucci, Gaia; Linser, Tobias; Faulhaber, Martin; Gatterer, Hannes; Ott, Guenter; Linser, Armin; Ehrenbourg, Igor; Tkatchouk, Elena; Burtscher, Martin; Bernardi, Luciano

Abstract

http://www.researchgate.net/publication/7474551_VO2_responses_to_intermittent_swimming_sets_at_velocity_associated_with_VO2max

Authors:

http://www.researchgate.net/publication/8097717_Effects_of_hypoxic_interval_training_on_cycling_performance

Oct 06,2010 - Dubai, UAE – 6 October, 2010: For decades, spending time in high altitude conditions has been the most successful natural method to effectively enhance oxygen absorption, transport and utilisation by the body. With the prevalence of type 2 diabetes mellitus and metabolic syndrome one of the highest in the world, discoveries in molecular medicine showing the enormous potential in targeted usage of high altitude climate conditions allows for new strategies for therapy and prevention of the disease in the UAE.

According the Dr Richard Reyes, founder and medical director of the Reyes Longevity Programme, there is a well defined sequence of molecular events which result in the correction of the components of the metabolic syndrome; high cholesterol and triglycerides, high blood pressure, low HDL, type 2 diabetes and insulin resistance.

“The main difference in high altitudes compared to sea level conditions is the decreasing air pressure with increasing height,” says Dr Reyes. “As the air gets ‘thinner’ and the body absorbs less oxygen, the heart rate and breathing increases. The low oxygen saturation in the blood, also known as hypoxia, causes a chain of positive biological adaptations. An increase in red blood cell production, better utilisation of nutrients in muscles and tissues, increased economy of the cardiovascular system and the optimisation of the heart rate at rest are only a few examples of how high altitude conditions can work towards correcting the components of the metabolic syndrome.”

Dr Reyes will be speaking at the 3rd International Congress in Aesthetic, Anti-Aging Medicine & Medical Spa Middle East (ICAAM), which will be held at the Al Bustan Rotana Hotel, Dubai, UAE from 26 to 27 November 2010. Leading experts in aesthetics and anti-aging medicine will be on site to demonstrate latest techniques and showcase latest anti-aging research such as the use of high-altitude climate to correct the metabolic syndrome.

“Changes in response to high altitude can be seen after just one or two hours of training exposure per week,” says Dr Reyes. “Correcting the disrupted metabolic process can go a long way towards slowing down the aging process. Cellular aging is understood in part to be due to the accumulation of the effects of oxidative stress and free radical formation. Exposure to altitude counteracts both of these – it is well recognised that people who live in the mountains have longer lives than those at sea level.”

http://bignews.biz/?id=925256

Medicine and science in sports and exercise. 01/09/2006;

http://www.researchgate.net/publication/6899290_Leukocyte%27s_Hif-1_expression_and_training-induced_erythropoietic_response_in_swimmers