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 Among two groups of men sent on a hiking vacation,
one at sea level and the other at just over 5,500 feet altitude,
benefits were about the same and no negatives were seen, suggesting
that exercising in the thinner air at altitude is neither better nor
riskier for health, the researchers say.
"The data of the AMAS-2000 study proved that daily hiking for hours
at any altitude provides cardiovascular benefits and represents an
excellent therapeutic opportunity for physical and mental
regeneration even for individuals with a cluster of cardiovascular
risk factors," Dr. Guenther Neumayr told Reuters Health in an email.
Metabolic syndrome is a cluster of characteristics, including
abdominal obesity, high cholesterol and triglycerides, high blood
sugar and elevated blood pressure. People with metabolic syndrome
are at greater risk for cardiovascular disease and diabetes.
Neumayr, a medical doctor practicing in Lienz, Austria, was part of
the team that designed the Austrian Moderate Altitude Study 2000
(AMAS-2000) to determine if hiking at a moderately high altitude
might be any different from hiking at low altitude.
Between 5,000 and 8,000 feet above sea level is considered moderate
altitude. Cities within that range include Albuquerque, New Mexico;
Denver, Colorado; Nairobi, Kenya; Lima, Peru and Mexico City.
The air pressure at that altitude is similar to what it feels like
to be on a commercial airplane. And the oxygen concentration in the
air is approximately 17 percent, compared to 21 percent at sea
level.
To test whether exercise at moderate altitude posed any additional
risks or offered extra benefits, the researchers recruited 71 men,
ranging in age from 36 to 66 years old, and randomly assigned them
to three-week vacations at one of two Austrian resorts located in
Obertauem, at 5,577 feet above sea level, or in Bad Tatzmannsdorf,
at 650 feet above sea level.
The men all had metabolic syndrome and were non-smokers, the
researchers note in their report, published in the journal
Wilderness and Environmental Medicine.
Health professionals led the men on moderate intensity hikes that
lasted more than two hours each. They hiked four days a week and
rested the other three. The men in both groups also had similar
diets, averaging about 1,800 calories per day.
The researchers weighed the men, measured their abdominal and hip
circumferences and took blood samples several times during the
study.
At the end of three weeks, men in both groups had lost an average of
7 pounds and showed similar drops in blood pressure readings, heart
rate, blood sugar and similar improvements in cholesterol.
In both groups, for example, resting heart rate fell by just under
three beats per minute from measurements taken two weeks before the
vacation to measurements six to eight weeks afterward. In the group
that exercised at altitude, blood pressure dropped from an average
187/94 to 179/90, compared to the sea level group whose average
readings went from 191/96 to 184/87.
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"It is the daily activity, not the altitude which provides the
benefits in the health effects," Neumayr said.
Past research had suggested that hiking or skiing at a moderate
elevation can increase the risk of cardiac arrest, however, those
studies also found that cardiac events tended to happen on the first
day at a higher altitude and that people who had already had a heart
attack were the ones most at risk, Neumayr and his colleagues write.
All the participants in the new study tolerated the vacations well
and no adverse events were seen at either altitude, they add.
"Walking and hiking are activities of low to moderate exercise
intensity which can be performed by nearly everyone — even by
patients with metabolic syndrome featuring obesity and poor
cardio-respiratory fitness," Neumayr said.
The difference in air pressure between the two altitudes is
marginal, he pointed out.
"Therefore, there is no significant effect on the individual's
performance between these two altitudes — everyone featuring bad
fitness has, of course, to exercise for some time at sea or low
level to be able to start effective training," he said.
Neumayr said that years with insufficient physical activity have led
to higher rates of obesity and metabolic syndrome.
"Thus, walking and hiking — the original forms of motion — should be
recommended generally and generously for both healthy people and
patients with metabolic syndrome," he said.
People with health conditions such as chronic obstructive pulmonary
disease or who have been diagnosed with heart disease may have
difficulty breathing at higher altitude and should talk to their
doctor before traveling to cities located at moderate or higher
elevations. ___
Source: http://bit.ly/1ihQkX0
Wilderness and Environmental Medicine,
online April 14, 2014.
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