High-intensity interval training rapidly improves diabetics’ glucose metabolism


University of Turku


research reveals that high-intensity interval training (HIIT) increases glucose
metabolism in muscles as well as insulin sensitivity in type 2 diabetes. After
just a two-week training period, the glucose uptake in thigh muscles returned
to a normal level.

New research reveals that high-intensity
interval training (HIIT) increases glucose metabolism in muscles as well as
insulin sensitivity in type 2 diabetes. Already after a two-week training
period, the glucose uptake in thigh muscles returned to a normal level.

The discovery was made in a research
project led by Senior Research Fellow Kari Kalliokoski and Project Manager
Jarna Hannukainen at the University of Turku, Finland. The project studied the
health impacts of high-intensity interval training on healthy people and
diabetics, and the results are encouraging.

“HIIT has a rapid impact on
metabolism. However, no great differences have been demonstrated between the
impact of HIIT and moderate intensity continuous training over a longer period
of time. The main benefit of high-intensity interval training is mostly that it
takes less time,” says Doctoral Candidate Tanja Sjöros.

First in the study, healthy men in their
forties and fifties did either high-intensity interval training or traditional,
moderate intensity training. Later, a group of people with insulin resistance
carried out a similar two-week training routine. Some of them had type 2
diabetes and some prediabetes, i.e. their blood sugar levels were elevated but
not yet high enough to indicate type 2 diabetes.

“Before the training started, the
glucose metabolism and insulin sensitivity of the insulin resistant persons were
significantly reduced compared to the group of healthy individuals. However,
already after two weeks of high intensity training, which amounted to six
training sessions, the glucose metabolism in the thigh muscles achieved the
starting level of the healthy control group,” tells Sjöros.

In HIIT, the training sessions are highly
intensive but short and followed by recovery period. For example, HIIT can be
carried out in 30-second training sessions of maximum intensity and with a
recovery sessions of a couple of minutes.

Glucose metabolism and insulin sensitivity
improved after both the high-intensity training and the moderate intensity
continuous training, so the study suggests that people can choose the type of
training based on their own preferences.

“However, the group that did moderate
intensity training achieved only half of the improvement experienced by the
HIIT group during the two-week period. Therefore, this type of training
requires a longer period of time. If you have only little time to spare,
high-interval training could be a great alternative to traditional training
that requires more time but is lower in intensity,” says Sjöros.

HIIT also improves endurance. In the study,
the endurance of type 2 diabetics increased only in the HIIT group, but earlier
studies have shown that, when the training routine continues for over two
weeks, endurance increases with the traditional, moderate intensity training
just as much as it does with high-interval training.

The research results published in the Scandinavian Journal of Medicine
& Science in Sports
highlight the beneficial effects of
exercise on glucose metabolism especially in diabetics and in those who suffer
from disturbances in the glucose metabolism. According to previous research,
exercise lowers blood sugar as much as diabetes medication. Therefore, exercise
is an essential part of treating and preventing diabetes.

“It’s particularly good news that when
it comes to the glucose metabolism and endurance it does not seem to matter in
whether the exercise takes place over a longer period of time as moderate
training or over a short period as high-interval training. Everyone can choose
the type of training that suits them best. In general, you can achieve the best
results for you body by using both training methods,” encourages Sjöros.

However, the researchers advise that
diabetics should consult their doctor before starting a new exercise routine.
For example, if the amount of exercise increases significantly, it might be
necessary to check the diabetes medication. Also other possible illnesses have to
be kept in mind when planning a new exercise routine.

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Journal Reference:

1.    Tanja J. Sjöros, Marja A. Heiskanen, Kumail K. Motiani,
Eliisa Löyttyniemi, Jari-Joonas Eskelinen, Kirsi A. Virtanen, Nina J. Savisto,
Olof Solin, Jarna C. Hannukainen, Kari K. Kalliokoski. Increased insulin-stimulated glucose
uptake in both leg and arm muscles after sprint interval and moderate intensity
training in subjects with Type 2 Diabetes or Prediabetes
. Scandinavian Journal of Medicine
& Science in Sports
, 2017; DOI: 10.1111/sms.12875