THURSDAY, Dec. 15 (HealthDay News) -- Lack of time is a common
reason cited for not exercising, but new research suggests that
several short intensive workouts a week may help lower blood sugar
levels similarly to longer, more regular exercise regimens.
The small, new study found that 30 minutes of high-intensity
exercise a week -- a total exercise time of 75 minutes a week with
warm-up and cool-down included -- could lower blood sugar levels
for 24 hours after exercise, and help prevent post-meal blood sugar
spikes in people with type 2 diabetes.
"If people are pressed for time -- and a lot of people say they don't have enough time to exercise -- our study shows that they can get away with a lower volume of exercise that includes short, intense bursts of activity," said the study's senior author, Martin Gibala, professor and chair of the department of kinesiology at McMaster University in Hamilton, Ontario, in Canada.
Results of the study are published in the December issue of the
Journal of Applied Physiology.
Experts already know that exercise can lower blood sugar levels,
according to the U.S. National Institute of Diabetes and Digestive
and Kidney Diseases. Muscles use glucose as fuel, so any type of
activity can bring blood sugar levels down. Exercise also helps the
body use insulin more efficiently, which in turn, helps the body
use more glucose.
Current recommendations from the American Diabetes Association
suggest that people with diabetes should try to get at least 150
minutes of moderate to vigorous exercise each week. That's about 30
minutes a day, most days of the week.
But, not everyone has time to do that much exercise, Gibala
noted. So he and his colleagues wanted to see if high-intensity
exercise, done for a shorter time, could also have an impact on
blood sugar levels.
The study included eight people with type 2 diabetes. Their
average age was 63, and their body mass index (BMI) was 32, a level
considered obese. BMI is a measurement of body fat that takes into
account height and weight.
Over two weeks, the study participants completed six sessions of
high-intensity training. For one minute, the study participants
would exercise intensely, followed by a minute of rest. This was
then repeated until they'd completed 10 minutes of intense
exercise. The exercise sessions also included a warm-up and
cool-down period for a total of 25 minutes of exercise.
The intense exercise was done at a level to get the heart rate
to about 90 percent of their maximal heart rate. Gibala said this
means you're exercising
really hard for that minute. "You're not at an all-out pace,
like you're trying to save your child, but you'll definitely be out
of breath and have trouble talking after a minute," he said.
The best thing about this type of exercise is that "these
intervals can be scaled to your level of fitness so that it's safe
and effective for you," he noted.
In addition to testing blood sugar levels throughout the study,
the researchers also biopsied thigh muscles from each participant
at the start of the study, and after the last bout of exercise.
The investigators found that blood sugar levels dropped from 137
milligrams per deciliter (mg/dL) to 119 mg/dL. In addition, blood
sugar levels after meals were also reduced long after training
sessions were complete.
The biopsies from the thigh muscles showed increased skeletal
mitochondrial capacity, an indicator of improved metabolic
health.
Gibala said there are more glucose-transport proteins in the
blood after exercise, and these transporters move glucose into the
muscles. That's why there's less glucose in the blood.
Dr. Joel Zonszein, director of the Clinical Diabetes Center at
Montefiore Medical Center in New York City, agreed that short bouts
of exercise can help the body better use glucose, but that more
exercise is better.
"If you can only do five to 10 minutes of exercise, that's better than nothing, but you really start to see the effects of exercise if you can regularly exercise 20 to 30 minutes at least a few times a week," he said. "Constant training leads to a steady demand for glucose."
More information
Learn more about exercise and diabetes from the
U.S. National Institute of Diabetes and Digestive ...
Kidney Diseases.