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June
2001
Walk,
Don't Run for Weight Loss
People often
disrupt their sedentary lifestyles with bouts of high-intensity
exercise, like running or aerobics, to avoid gaining weight or
developing heart disease. But a new study shows spending some
of your day engaged in moderate activity, like biking, walking,
or even taking the stairs at work, may be more a successful method
for boosting daily calorie expenditure and losing weight.
The study, published in Nature, involved 30 healthy,
non-obese women and men. For two weeks, the participants’ energy
expenditure was measured, while their activity levels were
tracked using portable motion sensors and activity diaries.
The investigator found the amount of moderate activity, not
vigorous exercise, was a significant predictor of total energy
expenditure. He hypothesized that moderate activity usually
occupies a larger portion of the day compared to more vigorous
exercise. For instance, studies on obese subjects have found
adding intense exercise to diet didn’t enhance weight
loss because the extra energy expenditure didn’t offset
the reduced time spent on other physical activities.
This small, but informative study provides strong evidence
that exchanging some of time you sit in front of a TV for moderate
activity increases total daily energy expenditure and metabolic
rate. Short bursts of vigorous activity in an otherwise inactive
and unhealthy lifestyle is not enough. So take the stairs,
not the elevator, and go for a walk at lunch. But don’t
be discouraged from going for a run. Aerobic activities, like
jogging, swimming and brisk walking, help make your heart stronger
and more efficient, which can lower your heart disease risk
still further.
June
2001 Update
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FDA
Approves First Automatic and Non-Invasive Blood Glucose Monitor
People with diabetes who regularly monitor their blood glucose
levels are less likely to develop the disease’s complications
such as heart disease, blindness and kidney disease. Unfortunately,
traditional blood glucose monitoring is time-consuming and requires
sticking the finger for blood. So many diabetics test themselves
less frequently than recommended.
A new bloodless glucose-monitoring device recently approved by
the FDA could make monitoring easier. Made by Cygnus Inc., GlucoWatch
Biographer is a prescription wristwatch-like device with sensors
on its underside that monitor glucose levels. By a process called reverse
iontophoresis, it applies a very low electric current to extract
glucose samples from the skin’s interstitial fluid every 20
min for 12 hours, even during sleep. The device, which must be
first calibrated using a finger-prick reading, stores the readings
and sounds an alarm if the glucose reaches a pre-selected level.
The FDA approved the device on the basis of clinical trials done
on both type I and type II adult diabetics. No research has been
conducted on children. The studies compared GlucoWatch readings
with traditional finger-prick blood glucose tests and found measurements
were fairly consistent. However, up to 25% of the time, the results
differed by more than 30% and sometimes GlucoWatch gave completely
erroneous readings. The device was less effective at detecting
very low glucose levels than very high levels. Also, it was not
accurate if the patient’s arm was too sweaty and perspiration
is common with hypoglycemia, or low blood sugar. GlucoWatch
caused skin irritation in up to 50% of users.
GlucoWatch should not be used as a replacement for finger-prick
blood tests. Any treatment decisions and all alarm values should
be confirmed with blood glucose tests. But as the first automatic
and non-invasive device, GlucoWatch may help patients better manage
their diabetes.
June
2001 Update
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Surgery
for GERD
In recent
years, people suffering from severe, chronic heartburn that can’t
be controlled with medications have turned to surgery with hopes
for permanent relief and the prevention of esophageal cancer.
But the results of a recent study that assessed the well being
of patients a decade after they had surgery question its benefits.
Heartburn, also known as gastroesophageal reflux disease (GERD),
occurs when the opening between the esophagus and stomach relaxes
spontaneously, allowing acidic gastric juices to flow into
the esophagus and cause irritation. Medications for GERD include
antacids, proton pump inhibitors that decrease the amount of
acid produced, and drugs that increase the tightness of the
esophageal. Surgery, an option usually reserved for hard-to-treat
GERD, involves folding the top of the stomach around the end
of the esophagus to create a tighter opening. This procedure
has become more popular with the development of minimally invasive
techniques.
A study from the late 1980s of 247 heartburn patients found
surgery was better than medication at controlling symptoms.
However, ten years later a follow-up study of 239 of the original
patients found many of the patients who underwent surgery still
suffered from heartburn. Though their symptoms were less intense
than those who received medication in the original study, 62%
of the surgical patients still took antireflux medication regularly
(compared to 92% of the medical patients).
The study also found that surgery failed to significantly decrease
the risk for esophageal cancer compared to treatment with medication.
Chronic heartburn is a risk factor for this cancer. However,
the small size of the study combined with the low incidence
of esophageal cancer did not rule out the possibility of a
difference. A more surprising result of the study showed surgical
patients were more likely to die than patients on medication.
These deaths were not related to the surgery, but close to
half (48%) were related to heart disease. The researchers were
unprepared for this result and therefore have no data to explain
this finding.
The results of this study suggest that while surgery may do
a better job at controlling the symptoms of heartburn, it doesn’t
eliminate the need for medication or decrease cancer risk.
In general, surgery should be seen as an option of last resort
for those patients whose symptoms are hard to treat with medication.
June
2001 Update
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