the Role of Physical (In)activity in the Prevention and Treatment of Type 2 Diabetes
There are two types of diabetes (Type 1 and Type 2
Diabetes). Type 1 diabetes, only occurs in 5-10% of diabetic cases, it tends to
occur in early childhood/early adulthood. It is caused by the body’s immune
system destroying its own insulin-making cells (Beta-cells) of the pancreas. It
requires consistent treatment through the use of insulin injections (Chamberlain,
et al., 2016).
Type 2 diabetes, which I will discuss throughout this paper,
is when there is a progressive loss of insulin secretion and in most cases
there in an insulin resistance (Chamberlain, et al., 2016). Type 2 diabetes can
be completely prevented and in most cases it occurs in people that either have
a sedentary lifestyle and/or poor diet.
The symptoms a person may suffer that has type 2 diabetes
can vary from slight to extreme, such as; suffering from thirst, frequent
urination, blurred vision, unexplained rapid weight loss/gain and in most
severe cases the amputation of a limb (normally a leg or foot). This is caused
by nerve and blood vessel damage in the leg(s) or feet (Diabetes Ireland, 2018)
At present in Ireland there are 225,840 people suffering
with Type 2 diabetes, with at least 30,000 not actually been diagnosed with the
disease (Diabetes Ireland, 2018)
Prediabetes can also be diagnosed when blood glucose levels
are higher than the norm, but not quite high enough to be classified as
diabetes. When affected with higher blood glucose level there is an increased
chance of developing type 2 diabetes, this can be prevented/delayed with
lifestyle changes, such as becoming more active and changing your dietary
habits. I will discuss this further throughout.
Benefits of Physical
Activity with Type 2 Diabetes
There have been thousands of studies/researches conducted in
the area of ‘how physical activity can prevent type 2 diabetes’ but saying this
there is a lot of conflicting views/results. Some studies have shown how
aerobic exercise is more beneficial to prevent type 2 diabetes rather than
resistance training and some say resistance training is more beneficial. In my
opinion from looking through papers a combination of both would be the most
Aerobic training has been seen to have dramatic impact on
the human body, it increases insulin sensitivity, mitochondrial density, immune
function, cardiac output, oxidative enzymes, etc. (Garber, et al., 2011). It
has been proven that moderate to high intensity aerobic activity is associated
to lowering overall mortality risks in both type 1 and type 2 diabetes.
In people suffering with type 2 diabetes, regular aerobic
training has been shown to reduce insulin resistance, but high-intensity
interval training (HIIT) really rapidly enhances insulin sensitivity and
glycemic control in adults (Little, et al., 2011). I believe this study by
Little, et al., really shows us how important not only aerobic training is, but
In a study by Roberts, et al., 2013 acute bouts of exercise
and regular physical activity can really modify the insulin action in the
muscle and liver. This is actually backed up in a study by Nielsen et al.,
where they have actually proven that aerobic exercise actually increases muscle
glucose uptake fivefold through insulin independent mechanisms. After these
acute bouts of exercise glucose uptake remains elevated for up to 48 hours in insulin
When people with type 2 diabetes part take in resistance
training they improve their glycemic control; insulin resistance, blood
pressure, etc. but it has been shown not to have as significant of an impact to
aerobic exercise (Gordon, et al., 2009).
The combination of regular aerobic/endurance training with
resistance training may provide the greatest impact on glucose uptake an
insulin resistance (Wing et al., 2013), which in my opinion is the best way of
reducing the risk of type 2 diabetes. Not only does it reduce the risk of type
2 diabetes but it works the different energy systems in the body which is
always a positive.
It also depends on the intensity of the exercise undertaken
as, as little as twenty minutes exercise with near-maximal heart rate will
result in twenty-four hours regular insulin activity (Van Dijk, et al., 2012).
So as you can see there are many factors that actually effect how impactful
exercise is on individuals with type 2 diabetes.
Physical Activity in
Adults with Type 2 Diabetes
Wing, et al., 2013, conducted an intervention called the
Look Ahead Trial, which looked at a conducting a lifestyle intervention in
older adults suffering with type 2 diabetes. There was also a control group of
older adults who had diabetes support and education. It was shown that the lifestyle intervention
group had a weight loss of at least 7% through 175 minutes of exercise per week
and had a greater impact on insulin resistance. The control group did see
significant improvements but not as much as the lifestyle intervention group.
Saying this, I did
not like the way this study was conducted as the lifestyle intervention group
had to do their 175 minutes of exercise per week completely unsupervised, which
from my own experience most of the subjects would not have completed. Although,
there was clear improvements glycemic control in type 2 diabetics due to
aerobic training. As mentioned above aerobic exercise, along with resistance
training would be most beneficial for adults with type 2 diabetes.
Physical Activity in
Youths with Type 2 Diabetes
A randomized trial looking at treatment options in
adolescents diagnosed with type 2 diabetes was conducted by Hirst, et al.,
2012, showed us how again exercise improves their overall well-being. This
study also showed that it wasn’t just exercise that improved the adolescent’s
well-being; there was also a dietary intervention also. There was weight loss
and a positive impact on insulin resistance and blood glucose levels achieved
through a combination of physical activity and the dietary intervention.
As there is not much research within this age group
regarding the amount of physical activity they should be taking part in per
week it should be the same as adults, 60 mins per day, at moderate to vigorous
activity. More research needs to be conducted around youths dealing with type 2
diabetes as it is a growing problem throughout the world.
Treatment of Type 2 Diabetes
Prediabetes can be diagnosed when blood glucose levels are
higher than the norm, but not quite high enough to be classified as diabetes.
When affected with higher blood glucose level there is an increased chance of
developing type 2 diabetes, this can be prevented/delayed with lifestyle
changes. Structured lifestyle intervention trials that include physical
activity at least 150–175 min/week and dietary energy restriction targeting
weight loss of 5% 27% have demonstrated reductions of 40%–70% in the risk of
developing type 2 diabetes in people with impaired glucose tolerance (Church,
et al., 2010).
A study by Balk, et al., shows us that diet and physical
activity promotion programs reduced type 2 diabetes prevalence and fasting
blood glucose while improving other cardio metabolic risk factors. Trials
evaluating less resource-intensive lifestyle interventions have also shown
effectiveness through weight loss and lowering blood glucose level (Dunkley, et
al., 2014). As you can see both the Balk, et al. and Dunkley, et al., studies
show us how exercise not only not only is a great way to prevent type 2
diabetes, but it also shows that it reduces weight, lowers the risk of cardiac
As seen from all of the cases/study’s I have mentioned
above, there is a few conflicting views about resistance exercise and aerobic
exercise. But the overriding conclusion from the vast majority of study’s is
that when a combination of both resistance and aerobic training is introduced
into a person’s day to day living with type 2 diabetes, their chances of improving
insulin resistance and blood glucose levels.
Not only though does just exercise improve these, I also believe
that dietary habits is crucial to this. Not just as a stand-alone intervention
both exercise and diet interventions should be prescribed to all those
suffering with type 2 diabetes.
Type 2 diabetes in the youth population is a growing problem
as mentioned above, much more research needs to be conducted in this area to
prevent type 2 diabetes occurring at such a young age.
Diabetes is growing rapidly in the ‘Western World’ due the
increase in demand for fast food. So I believe that diabetes prevention should
be studied further and implemented more and more by governments rather than
looking into diabetes treatment. If we can prevent type 2 diabetes from
occurring it’ll have a huge benefit on the world’s economy.
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