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VOLUME 16 NUMBER 1 • JULY 2019
CLINICAL COMMENTARY
SA JOURNAL OF DIABETES & VASCULAR DISEASE
The effect of exercise on diabetes management
TJ Ellapen, A Broodryk, Y Paul, P Buys
Correspondence to: Terry Ellapen
A Broodryk, P Buys
Physical Activity, Sport and Recreation (PhASRec), Faculty of Health Science,
North-West University, Potchefstroom
e-mail:
tellapen1@yahoo.comY Paul
Department of Sport, Exercise, Rehabilitation and Dental Therapy, Faculty of
Health Science, Tshwane University of Technology, Pretoria
S Afr J Diabetes Vasc Dis
2019;
16
: 40–43
Abstract
Regular exercise is a fundamental component of any strategic
diabetes-management plan. Habitual exercise provides
numerous physiological benefits to diabetic patients. It
is however naïve to believe that exercise does not induce
risk factors that may adversely impact on the health of a
diabetic patient. The objective of this clinical commentary is
to increase awareness of both the benefits and risks induced
by exercise among diabetic patients.
Keywords:
diabetes, exercise, benefits, risks
Diabetes mellitus is classified as a metabolic disease, which entails
either an absolute (type 1 diabetes mellitus) and/or a relative (type
2 diabetes mellitus) insulin deficiency.
1
Insulin-dependent diabetes
(type 1 diabetes mellitus) is an autoimmune condition, caused by
the assault on the person’s pancreas by the body’s own antibodies.
This has an impact on the beta-cells within the pancreas, resulting
in altered insulin production. Treatment for insulin-dependent
diabetes involves the injection of exogenous insulin.
Non-insulin-dependent diabetics (type 2 diabetes mellitus)
produce insulin, which may be insufficient or their cells are resistant
to it. Type 2 diabetes can produce significant health complications,
such as diabetic retinopathy, diabetic neuropathy, diabetic kidney
disease, and increase the risk of coronary artery diseases (CAD)
and strokes. Non-insulin-dependent diabetes can be managed
through medication, a proper nutritional plan, regular exercise and
reduction in body fat.
In 2017, it was estimated that 451 million people were
diagnosed with diabetes globally; a number which, as predicted by
the International Diabetes Federation, may escalate to 693 million
by the year 2045.
2
Hunter-Adams
et al
. reported that the incidence of diabetes in
Africa will increase by 110% in the period from 2013 to the 2035.
Furthermore, the prevalence of diabetes in South Africa will increase
concomitantly with the overarching African continental epidemic.
3,4
A concerning statistic is that only 43 to 50% of all diabetic patients
in Africa are presently diagnosed.
3
Durstine
et al
. reported that 80% of type 2 diabetes patients
are obese, adversely contributing to their pathology by increasing
insulin resistance.
1
Obesity is characterised by excessive body
fat, with an inverse decrease in lean muscle mass, decreasing an
individual’s blood glucose uptake and thereby predisposing the
person to diabetes mellitus.
1
The 2015 Global Burden of Disease
report identified hyperglycaemia and obesity as predisposing risk
factors contributing to premature death and disability among many
South Africans.
5
The World Health Organisation (WHO) has identified physical
inactivity (a sedentary lifestyle), commonly observed among
diabetic patients, as a leading cause of premature death.
6
A person
is considered physically active if the individual performs moderate
accumulative aerobic activity for 150 minutes/week, with an
exercise intensity ranging between three and six METs (metabolic
equivalent) or vigorous physical activity for 75 minutes/week at an
intensity greater than six METs.
6
One who does not comply with
these criteria may be considered physically inactive. Mickelsfield
et
al
. reported that 43 to 49% of all South Africans are physically
inactive.
7
In 2012, the South African Health Review reported that
of approximately 1 032 981 people identified as diabetic, only
57.4% were pharmacologically treated.
4
In 2016, the Global Health
Estimate reported that 972 0000 South Africans had died from
diabetes.
8
Presently diabetes-management strategies are centred on
identification, chronic medication, and dietary and exercise
counselling.
9
An electronic Google Scholar search (limited to
articles published in 2018) revealed 40 800 publications indicating
the benefits of exercise for diabetic patients. Despite the impressive
number of publications regarding the benefits of exercise for
diabetic patients, many South Africans still do not incorporate
regular exercise into their diabetes-management strategy.
Anecdotal reports suggest that numerous diabetic patients
interested in making regular exercise a part of their management
strategy simply join a health and wellness or fitness club and
commence exercising without proper nutritional and exercise
supervision. This commentary aims to increase awareness regarding
the beneficial impact of exercise among diabetic patients, taking the
potential risks induced by exercise into consideration and offering
recommendations in order to enable patients to better avoid these
risks.
The benefits of exercise and physical activity
Regular structured exercise is beneficial to diabetic patients and
offers the following advantages.
• Regular structured exercise lowers blood glucose concentration
during and after an exercise session.
10
Regular prolonged aerobic
exercise at moderate intensity level increases glucose absorption,
which reduces the hyperglycaemic state of diabetic patients.
This, coupled with increased insulin sensitivity, further increases
glucose absorption, thereby maintaining a lower glucose
state among diabetic patients. It is therefore important that
the diabetic patient carry snacks with him/her during exercise
in the event of exercise-induced hypoglycaemia. Moreover,
post-exercise meals are essential for the maintenance of a