Adolescence and Cognitive Enhancement: Importance of Physical Activity

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Exercise Physiology
Name of the Student
Name of the University
Author Note

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Adolescence an opportune phase for cognitive enhancement
Definition of adolescence and puberty
Adolescence is the transition state that exists in between childhood and adulthood.
This transition mainly occurs during the age bracket of 10 to 19 years and is mainly defined
as series of psychological and physiological changes in the body and mind of the individuals
[1]. The physiological change occurring during adolescence is known as puberty and it
mainly helps to attain sexual maturity. This physical transition or changes over any particular
individual occurring during puberty is mainly visible between 9 to 12 years. Thus
alternatively, puberty is regarded as the major life transition from non-reproductive juvenile
stage to reproductively competent adult stage [2]. Adolescence stage is extremely significant
in every person’s life as it is in this stage that the brain releases some special hormones that
promote both physical and cognitive development. Puberty and adolescence, the
developmental period associated with puberty is regarded as great physiological,
psychological and cultural changes. This is because, puberty and adolescence is associated
with great developmental plasticity [1].
Brain development during puberty
Recent advancement in the field of imaging technology has lead to the elucidation the
significant amount of brain development is associated during puberty and thus this stage is
treated as a special period in one’s life [3]. Puberty is characterised via physical, hormonal
and psychological transformation. Under this transformation, human brain undergoes
potential changes between the childhood and adulthood. The longitudinal sample analysis
study over 275 individuals (7 to 20 years), done via magnetic resonance imaging showed
significant changes in the sub-cortical region of human brain during puberty. Further studies
in this domain revealed that the pubertal development is extensively associated with the

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change in the structural volume of different parts of the brain in both the sexes. The main
regions of the brain which experience noticeable change during puberty include amygdale,
corpus striatum, hippocampus, nucleus accumbes (NA), globus pallidus (GP) and putamen
[4]. The imaging technique also revealed a striking change in the white and grey matter of
brain between 11 to 25 years of age along with increase in the connectivity between different
regions of brain along with the increase in the activity of the dopaminergic neurons in the
pre-frontal cortex of the brain. During puberty, there also occurs increase in the linkage
between the striatum and limbic system. These plausible changes in the anatomy and
physiology of the brain lead to change in the cognitive and behavioural characteristic of an
adolescent [3]. This drastic change in the anatomy of physiology of the brain occurring
during the puberty lead to significant change in the overall behavioural attitude of an
individual in comparison to that his or her childhood and thereby making him or her more
prompt in responding to questions [5]. This change in the cognitive thought process among
the adolescent due to change in the brain development increases the risk taking attitudes. The
subsequent hormonal changes occurring during puberty further exacerbates the overall brain
development and change in the neurological signalling [5].
Physical activity, heath benefits and cognitive development
Importance of physical activity across the lifespan and why is particularly impactful
during adolescence
Benefits of active lifestyle are not only restricted to physical health. Higher level of
physical exercise is associated with higher levels of cognitive performance among both the
younger adults and older adults. Cognitive functions are the special functions that are sub-
served via the interplay of the central nervous [6]. Evidence suggest that there exist a causal
relationship with the physical exercise and improved interplay between the different

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signalling pathways of the central nervous system and thereby leading to improved cognitive
development [6]. Mild to moderate physical activity like walking has been found to increase
the memory and attention among the older adults [7]. Increase in the rate of physical activity
during adolescence increase the rate of mean cerebral blood flow into the brain this in turn
help in the development of cognitive functioning. Not only this, increase in the overall
physical activity among the individuals who are in their pubertal stage helps to increase the
lactate threshold. This in turn causes an immediate increase in the plasma concentration of
adrenocorticitropic hormone, carecholamines, beta- endorphin and vasopressin in the
peripheral blood circulation which is thought to increase the secretion of neurotransmitter
secretion in the central nervous system causing elevated arousal and thus enhancing the
overall cognitive performance [6]. Additionally numerous neurotrophic factors like nerve
growth factor, brain-derived neurotrophic factor etc is found to get unregulated during
physical activity. These elevated levels of neurotrophic factors plays a crucial role in the
neural growth and neuron survival and thus influencing learning and overall memory
processes which are important for the cognitive functioning [6]. Physical activity also leads to
high physical fitness this in turn leads to higher cardiovascular fitness, larger volumes of
basal ganglia and hippocampus among the children who are in their adolescence. All these
cumulate into increase level of cognitive performance, memory development and thereby
leading to well-developed executive functions for day-to-day functioning [7].
Present trend of decrease in physical activity in school: review
International public health and health promotion organizations have highlighted that
the health risks across the lifespan are mainly associated with the decrease in physical
activity. The globally physical inactivity is found to increase the susceptibility of the
development of type 2 diabetes, breast cancer, colon cancer, rectal cancer and risk of
coronary heart disease [8]. This lack of physical activity and its relation to the development

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of the coronary heart disease is also prominent among the children who are in their
adolescence. However, in spite of the known relation between the lack of physical activity
and the subsequent threat of the physical and the mental health, there is lack of proper
awareness of physical activity in schools. However, the practising physical activity depends
on several determinants like physiological, sociocultural, psychological and ecological. For
example, in schools it has been found that the girls are less active than boys in the domain of
physical activity and the older children and adolescents are comparatively less active than the
younger children [8]. Another systematic review further highlighted that during the past 30 to
40 years the overall rate of physical activity in schools around the word has decreases
gradually. Given that the significant proportion of the total waking hours spent within the
school premises and in performing associated school activities, very less is known about the
physical activity of the students during their school hours and during the school-related after
school activities. In spite of having excellent research and prominent public health
surveillance systems, the present monitoring of the school-related physical activities among
the adolescence is inadequate [9]. Another research however, helped to throw light over the
current trends in the physical activities in schools. It showed that the majority of youth
worldwide now fail to meet the established physical activity standards. Increase in the class
duration and lack of proper game classes lead to increase in the sedentary behaviour among
the children. The sports are held annually and not on quarterly or semi-quarterly basis leading
to the decrease in interest in the overall physical activity or sports [10].
Mechanisms of exercise-induced cognitive enhancement
Exercise induced cognitive development demands both acute and chronic exercise as
evident from the research conducted over both human and animal models. Acute exercise is

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defined as single bout exercise and chronic exercise is characterised by repetitions of bouts of
exercise over time which lasts from weeks to years [11].
Table 1: Taxonomy of physical exercise
Type of
effect Mode of exercise
Type of
physiological
change
Type of brain mechanism
underpinning the effect
Acute Single bout of
exercise Transient
Modulation of the activity
of a neural network
Chronic Regular exercise Durable Patho-anatomical changes
in the brain structure
(Source: 11)
Acute pathway
Single session of exercise helps to increase the cognitive performance via the increase
in the overall flow of blood within the body along with the increase in release of the
neurotransmitter [11]. A meta-analysis conducted by Chang et al. (2012) highlighted that the
acute exercise do not have significant effect over the overall improvement of the cognitive
function of an individual but is effects on the cognitive ability is slightly greater than zero.
The range of cognitive benefits mainly depends on a number of factors that is duration of the
exercise and intensity of the exercise however, the improvement of the cognitive function is
more prominent among the individuals who are physically fit. Effects of the acute physical
exercise over the cognitive development during adolescence are mainly attributed by the
release of the brain-derived neurotrophic factor (BDNF). However, the effect of improve in
cognition is more pronounced in males in comparison to that of females and this is because,
decrease in the level of secretion of BDNF among the females [12]. In relation to BDNF, it

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can further be stated that the increase in the level of the physical activity via execution of the
acute physical exercise leads to increase in the level of secretion o BDNF in the peripheral
levels and increase in the intensity of the physical exercise help to increase in the secretion of
BDNF and thereby promoting modulation in the overall cognitive development [13].
Chronic pathway
Chronic exercise leads to the increase in secretion of the PGC-1a which in turn leads
to the activation of the FNDC5 pathway and thereby promoting the secretion of brain-derived
neurotrophic factor (BDNF) from the hippocampus of the brain and thereby facilitating the
overall development of the cognitive function [14]. FNDC5 pathway mainly leads to the
generation of elevated levels of irisin and this in turn induces the transcription of the BDNF
gene and other neuroprotective gene and thereby leading to the increase in the development
of cognition [14]. Chronic exercise pathway mainly encompasses endurance exercise which
is not only beneficial for the brain health and cognitive function but also promotes physical
health and well-being. The chronic exercise pathway is also reported to decrease the mental
health complications like depression [15]. Chronic physical exercise leads to the increase in
the rate of secretion of neuronal nitric oxide synthase (nNOS). The secretion of nNOS leads
to the promotion of angiogenesis in the human skeletal muscle. This increase in the rate of
angiogenesis after the endurance exercise in the human skeletal muscles leads to increase in
the overall blood circulation. The same has been proved by the comparative biopsies
conducted over the vastus lateralis (VL) muscle from 10 sedentary males and 10 males who
are under mild to moderate chronic exercise training. The increase in the overall blood
circulation increases the overall level of neurotransmission and thereby facilitating overall
cognitive development [16]. Chronic physical exercise pathway also promotes neuro-synaptic
genesis which in turn again facilitates better transmission of the neuronal impulses and

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thereby helping the population who are in their adolescences who improve on their cognitive
functions [17].