Exercise - makes you sound in mind and body
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Ancient man had to physically exert himself to
survive. What is now considered a form of physical exercise - walking
was their only mode of transportation. Thus physical exercise was a part
of one’s existence. This may explain why the Veddah community has been
shown to be devoid of diseases such as diabetes and hypertension (high
blood pressure). An editorial in a local newspaper has drawn attention
to the lack of physical activity among the population contributing to
the epidemic of obesity and diabetes (DN 9/2/09) and the social cost of
this change in life style.
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Dr. A.S. Dissanayake former Professor of Physiology,
Medical Faculty, Ragama
Physical activity is among the life style factors that have important
and independent effects on health, others being diet, smoking, and
alcohol use.
Physical activity is any bodily movement produced by the contraction
of skeletal muscle that increases energy expenditure above basal levels
(standing, walking slowly and lifting light weight objects as a part of
one’s daily life).
Health-enhancing physical activities include:
Aerobic activities include brisk walking, jogging, swimming, cycling,
jumping rope and dancing.
Exercise - a part of one’s daily life |
Muscle strengthening activities - lifting weights, children climbing
on playground equipment.
Bone-strengthening activities - Running, basketball, tennis, jumping
rope and hopscotch. Bone-strengthening activities can also be aerobic
and muscle-strengthening.
Physical activity affects many health conditions, and the specific
amounts and types of activity that benefit each condition vary.
Additional benefits occur with more physical activity. Benefits occur
across the board for children and adolescents, young and middle-aged
adults, older adults, and those in every studied racial and ethnic group
and even for those with disabilities including mental disabilities.
The health benefits on bodily functions include:
In children and adolescents
Improved cardio respiratory and muscular fitness
Improved cardiovascular and metabolic health biomarkers - rise in HDL
or ‘good’ cholesterol and fall in LDL or ‘bad’ cholesterol, better blood
sugar control are some.
Improved bone health and bone mass - Bone-strengthening activities
commonly produced by impact with the ground promotes bone growth and
strength.
Reducing body fat
Youth who are regularly active also have a better chance of a healthy
adulthood.
In adults and older adults, there is strong evidence to suggest that
exercise:
reduces risk of early death - people who engage in the amount of
exercise recommended below live an average of three to seven years
longer.
reduces coronary heart disease, stroke and high blood pressure -
effect are observed on virtually all risk factors of cardiovascular
disease.
Exercise causes the heart muscle tp contract forcefully and
frequently, increasing blood flow through the arteries leading to subtle
changes in the autonomic nervous system, which controls the contraction
and relaxation of these vessels.
This fine-tuning leads to a lower, lower blood pressure and a more
variable heart rate thus reducing the risk of cardiovascular disease.
Exercise also reduces inflammation associated with atherosclerosis which
contributes to heart attacks.
improves the blood lipid profile - by decreasing the amount of plasma
triglycerides - fatty molecules in the blood that are associated with
plaque build-up in the arteries. Physical activity helps reduce the
particle size of low-density lipoprotein (LDL) in the blood, and
increase amounts of high-density lipoprotein (HDL).
improves cardio-respiratory and muscular fitness.
may prevent and even reverse type 2 diabetes. In type 2 diabetes the
body begins to ignore or fails to produce enough insulin (insulin
resistance) causing a build up of fat leading to biochemical reactions
that interfere with the activity of insulin. Muscle activity increases
the beak down of fats reducing this action.
helps reduce abdominal fat - decreasing the risk of metabolic
syndrome a precursor of type 2 diabetes and coronary heart disease, said
to occur in commonly in South Asians.
prevents weight gain and induces weight loss, particularly when
combined with reduced calorie intake. Exercising may encourage people to
crave healthier unrefined foods (like fiber-rich cereals, lentils, leafy
vegetables etc.).
reduces risk of some cancers. Regular exercise lowers the risk
particularly for breast and colon cancer. Such effects are probably the
outcome of complex and subtle changes in hormone levels (insulin,
oestrogen and progesterone among them) and in the activity of the immune
system following regular exercise.
may also increase bone density, lower risk of hip fracture and
improve sleep.
The effects of exercise on the brain are less easily appreciated.
Most associate athleticism with lower academic performance. However,
evidence is accumulating to show that exercise has direct effects on the
brain.
In children, exercise:
reduces likelihood of them developing symptoms of anxiety and mental
depression
improves cognitive function - regular exercise in children appears to
improve brain function - cognition in particular. Some do not agree that
there is a clear cut effect but allowing sufficient time in the school
curriculum for daily exercise has been definitely shown not to impair
academic performance.
In adults there is very good evidence to show that exercise:
makes you smarter - It seems to do so by increasing brain blood flow
and the production of certain brain growth promoting molecules called
neurotrophins within specific areas of the brain such as the hippocampus
an area associated with what is called ‘executive control function’.
reduces depression - there is evidence to suggest that exercise helps
in treatment of depressive illness.
reduces the risk for Alzheimer’s disease and makes for better
functional health in older adults.
One may ask as to whether there are no adverse effects of exercise.
Many think that exercise increases the risk of sudden death from heart
attacks or incurring bodily injury. The benefits of exercise far
outweigh the risks.
Exercise guidelines:
Inactive individuals should have themselves checked out by their
doctor prior to commencing an exercise regime.
How much exercise and how frequently?
The guidelines issued recently by the U.S. Department of Health and
Social Security are:
For adults walking is a good way to get aerobic physical activity.
Walking has many health benefits and a low risk of injury. It can be
done year-round and in many settings.
The accumulated time spent has a greater impact on the health status
than frequency.
To reduce risk of injury, start slowly and increase the amount of
physical activity gradually over a period of weeks to months. For
example, an inactive person could start with a walking program
consisting of 5 minutes of slow walking several times each day, 5 to 6
days a week.
The length of time could then gradually be increased to 10 minutes
per session, 3 times a day, and the walking speed could be increased
slowly. In the long term one should aim at doing about 150 minutes of
accumulated exercise per week.
The good news is that “some is better than none”, some health
benefits are seen even when one does as little as 60 minutes a week of
aerobic exercise.
Adults should also do muscle-strengthening activities (lifting light
weights) that are moderate or high intensity and involve all major
muscle groups on 2 or more days a week.
Children and adolescents should do 60 minutes (1 hour) or more of
physical activity daily.
Most of this should be in the form of aerobic activities done at
least 3 times a week and of moderate to vigorous intensity.
Muscle strengthening and bone strengthening activities should also be
included. Bone-strengthening activities remain especially important for
children and young adolescents because the greatest gains in bone mass
occur during the years just before and during puberty. It is important
to encourage young people to participate in physical activities that are
appropriate for their age, enjoyable, and that offer variety.
Time has to be found for both structured and unstructured physical
activity during school and outside of school.
In our state schools, 80 minutes (2 periods a week) are set aside for
physical education from Grade 6 through 9 and is optional for Grades 10
and 11. In addition those in Grade 6 and upwards are also required to
engage in daily static physical activity for 15 minutes in the morning
prior to commencing classes.
Sadly, however, as a result of the educational rat race these
guidelines are observed in the breach more so in the National schools.
Thus given the alarming increase in childhood obesity and type 2
diabetes in our school children and the effects on the body, there is
much to be said for adding a 4th R - ‘running’ to the three traditional
Rs in our schools. Doing so, coupled with healthy nutrition and
restriction of television and internet usage will definitely help stem
the epidemic of childhood obesity and type 2 diabetes while improving
overall health and possibly even improving academic performance. |