The document is an investigatory project on the neurobiological and systemic effects of chronic stress, completed by G. Meenaloshini under the guidance of Mr. Pradeep Kumar for the academic year 2019-20. It details the nature of stress, its types and stages, how it affects various bodily systems, and strategies for stress management including diet and lifestyle changes. The project also includes acknowledgments, a content outline, and bibliographic references for further reading.

1. 1
BIOLOGY INVESTIGATORY
PROJECT
ACADEMIC YEAR 2019-20
UNDER THE GUIDANCE OF:
MR. PRADEEP KUMAR
SUBMITTED BY:
G.MEENALOSHINI
CLASS XII A
REGISTER NO:

2. 2
Acknowledgement
In the accomplishment of this project successfully, many people
have best owned upon me their blessings and the heart pledged
support. This time I am utilising to thank all the people who have
been concerned with this project.
Firstly, I would thank God for being able to complete this project
with triumph. Then I would like to thank my parents and family
members who helped me with their valuable suggestions.
Secondly, I would like to express my special thanks of gratitude to
my biology facilitator Mr. Pradeep Kumar as well as our principal
Mrs.G.Jigi Mol who gave me the golden opportunity to do this
wonderful project on the topic “NEUROBIOLOGICAL AND
SYSTEMIC AFFECT OF CHRONIC STRESS”, which also helped me
in doing a lot of research and I came to know about so many new
things.
Last but not the least I would like to thank all my friends and
classmates for their guidance in various phases of the completion
of the project.
Regards,
G.Meenaloshini

3. 3
CONTENT
S.NO TOPIC PG.NO
1
Introduction
4
2
What is stress?
5
3 What are the three stages of stress? 6-7
4
Stress response-how it works?
8-9
5
How stress causes illness?
10-13
6
What are the signs of too much stress?
14
8 How to manage stress? 15-16
9
Is there a stress management diet?
17
10
Statistics on stress
18-19
11
Bibliography
20

4. 4
INTRODUCTION
AIM OF THE TOPIC: Everyone feels stressed from time to time. But what is
stress? How does it affect our health? And what can we do about it?
The body is an incredible machine comprised of cells, tissues, and organs all working
together to sustain life.
To keep the body functioning normally throughout our lifetime, the body uses its
eleven organ systems (integumentary, muscular, skeletal, nervous, circulatory,
lymphatic, respiratory, endocrine, urinary/excretory, reproductive, and digestive) to
check and balance itself in an effort to maintain a relatively constant and stable state
of internal balance (equilibrium). This process is called Homeostasis: a process that
living things use to actively maintain stable conditions necessary for survival.
These systems work together to control body temperature, blood pressure, heart
rate, respiration, PH balance, CO2 balance, and so on. These systems manage the
body automatically in spite of the ever-changing internal and external conditions.
As long as we live a healthy lifestyle, such as eating a healthy diet, keeping stress to
a minimum, getting regular exercise, and getting sufficient rest and good sleep, the
body does a good job of maintaining itself, for the most part, all by itself.

5. 5
WHAT IS STRESS?
Stress is a feeling of emotional or physical tension. It can come from any
event or thought that makes you feel frustrated, angry, or nervous. Stress
is your body's reaction to a challenge or demand. In short bursts, stress
can be positive, such as when it helps you avoid danger or meet a
deadline. But when stress lasts for a long time, it may harm your health.
TYPES OF STRESS:
ACUTE STRESS: CHRONIC STRESS:
This is short-term stress that goes
away quickly. You feel it when you
slam on the brakes, have a fight with
your partner, or ski down a steep
slope. It helps you manage
dangerous situations. It also occurs
when you do something new or
exciting. All people have acute stress
at one time or another.
This is stress that lasts for a longer
period of time. You may have chronic
stress if you have money problems,
an unhappy marriage, or trouble at
work. Any type of stress that goes on
for weeks or months is chronic stress.
You can become so used to chronic
stress that you don't realize it is a
problem.

6. 6
WHAT ARE THE THREE STAGES OF STRESS?
The stress response and the General Adaptation Syndrome (GAS)
To enhance our ability to survive and enjoy a long life, the body has a
special survival mechanism that engages when we believe we could be in
danger. Walter Bradford Cannon, an early 20th-century American
physiologist, professor and chairman of the Department of Physiology at
Harvard Medical School, called this system the “fight or flight response”.
It’s also often referred to as the stress response, the emergency
response or the fight, flight, or freeze response (because some people
freeze like a “deer caught in headlights” when they feel overly stressed or
afraid).
Dr. Hans Selye, a 20th-century Vienna-born scientist well-known for his
work on stress and the author of, “The Stress Of Life,” identified three
specific stages of the stress response. He called these stages the
“General Adaptation Syndrome” (GAS). They are:
Alarm stage - Sensing danger triggers the stress response.
The stress response causes the secretion of stress
hormones into the bloodstream where they travel to
targeted spots in the body to bring about specific
physiological, psychological, and emotional changes that
enhance the body’s ability to deal with a threat – to fight or
flee.
Resistance stage – The stress response changes are
engaged to give the body an extra “boost” in energy and
resources to deal with a threat.
Exhaustion stage – After the threat has passed, the stress
response ends, and the stress hormones are used up or
expelled, the body enters a recovery phase where it
recovers from the stress response changes and rebuilds its
energy stores for next time a stress response is needed.

7. 7
For simplicity sake, the three stages of an
emergency response can be illustrated as:

8. 8
THE STRESS RESPONSE – HOW IT WORKS
Two-phase Stress Response
To accommodate different degrees and lengths of threats, the stress response has
two phases.
Phase One - Sympathetic Adrenomedullar System (SAM)
Sympathetic Adrenomedullar System (SAM) provides an immediate physiological,
psychological, and emotional adaptation that results in a short-lasting response, such
as an increase in alertness, danger surveillance, vigilance, and risk assessment that
enables strategic decision-making about the threat.
This initial response to danger is fast but not accurate, meaning the burst of
adrenaline is designed to get us out of danger immediately. Once out of danger, then
we can think about the threat and decide more appropriate ways of managing it.
For example, the moment we sense danger, the amygdala (often referred to as the
fear center of the brain because of its primary role in managing fear) signals the
hypothalamus (remember, it’s the “command center” of the brain). The hypothalamus
mildly stimulates the sympathetic nervous system, which in turn causes the medulla
part of the adrenal glands to release adrenaline and noradrenaline (which are
stimulants) into the bloodstream.
Adrenaline (epinephrine) and noradrenaline (norepinephrine) produce a mild form of
stimulation with a relatively short duration (a few minutes or so). Like other
hormones, their effects are targeted in that they only affect certain parts of the body
that have adrenaline and noradrenaline receptor sites, and their effects only last for
so long. Overall, these hormones are limited in what they can do and how long they
can do it.

9. 9
For example, adrenaline and noradrenaline stimulate the sympathetic nervous
system, which in turn:
Increases heart rate (noradrenaline increase heart contractions).
Increases blood pressure.
Increases oxygen in the lungs by opening the small airways in the lungs.
Shunts blood from non-vital organs and digestive system to muscles, the brain, and
vital organs.
Dilates pupils.
Increases sensory perception (senses become heightened).
Increases blood sugar and fats by releasing them from storage sites in the body.
Increases the body’s metabolism.
These changes quickly gear the body up for immediate action.
If the threat was only momentary, the stress response would end and the body would
enter the exhaustion/recovery phase.
Phase Two – Hypothalamic Pituitary Adrenal axis (HPA)
If the danger is perceived as more threatening or persists for more than a few
minutes or so, the amygdala signals the hypothalamus. The hypothalamus releases
corticotropin-releasing hormone (CRH). This hormone stimulates the pituitary gland,
which causes it to release adrenocorticotropic hormone (ACTH). ACTH stimulates the
adrenal cortex, which releases cortisol, the body’s most powerful stress hormone, into
the bloodstream.
Cortisol has a more dramatic effect on the body and its effects are longer-lasting.
Cortisol elicits a more significant response because its effects are broader and more
potent than those of adrenaline and noradrenaline.

10. 10
HOW STRESS CAUSES ILLNESS?

11. 11
HOW STRESS AFFECTS THE BODY?

12. 12
THE EFFECTS ON THE ORGAN SYSTEMS:
CENTRAL NERVOUS AND ENDOCRINE SYSTEMS
Your central nervous system (CNS) is in charge of your “fight or flight” response. In your
brain, the hypothalamus gets the ball rolling, telling your adrenal glands to release the stress
hormones adrenaline and cortisol. These hormones rev up your heartbeat and send blood
rushing to the areas that need it most in an emergency, such as your muscles, heart, and other
important organs.
When the perceived fear is gone, the hypothalamus should tell all systems to go back to
normal. If the CNS fails to return to normal, or if the stressor doesn’t go away, the response
will continue.
Chronic stress is also a factor in behaviours such as overeating or not eating enough, alcohol
or drug abuse, and social withdrawal.
RESPIRATORY AND CARDIOVASCULAR SYSTEMS
Stress hormones affect your respiratory and cardiovascular systems. During the stress
response, you breathe faster in an effort to quickly distribute oxygen-rich blood to your
body. If you already have a breathing problem like asthma or emphysema, stress can make it
even harder to breathe.
Under stress, your heart also pumps faster. Stress hormones cause your blood vessels to
constrict and divert more oxygen to your muscles so you’ll have more strength to take
action. But this also raises your blood pressure.
As a result, frequent or chronic stress will make your heart work too hard for too long. When
your blood pressure rises, so do your risks for having a stroke or heart attack.
DIGESTIVE SYSTEM
Under stress, your liver produces extra blood sugar (glucose) to give you a boost of energy.
If you’re under chronic stress, your body may not be able to keep up with this extra glucose
surge. Chronic stress may increase your risk of developing type 2 diabetes.
The rush of hormones, rapid breathing, and increased heart rate can also upset your digestive
system. You’re more likely to have heartburn or acid reflux thanks to an increase in stomach
acid. Stress doesn’t cause ulcers (a bacterium called H. pylori often does), but it can increase
your risk for them and cause existing ulcers to act up.
Stress can also affect the way food moves through your body, leading to diarrhea or
constipation. You might also experience nausea, vomiting, or a stomach ache.

13. 13
MUSCULAR SYSTEM
Your muscles tense up to protect themselves from injury when you’re stressed. They tend to
release again once you relax, but if you’re constantly under stress, your muscles may not get
the chance to relax. Tight muscles cause headaches, back and shoulder pain, and body aches.
Over time, this can set off an unhealthy cycle as you stop exercising and turn to pain
medication for relief.
SEXUALITY AND REPRODUCTIVE SYSTEM
If stress continues for a long time, a man’s testosterone levels can begin to drop. This can
interfere with sperm production and cause erectile dysfunction or impotence. Chronic stress
may also increase risk of infection for male reproductive organs like the prostate and testes.
For women, stress can affect the menstrual cycle. It can lead to irregular, heavier, or more
painful periods. Chronic stress can also magnify the physical symptoms of menopause.
IMMUNE SYSTEM
Stress stimulates the immune system, which can be a plus for immediate situations. This
stimulation can help you avoid infections and heal wounds. But over time, stress hormones
will weaken your immune system and reduce your body’s response to foreign invaders.
People under chronic stress are more susceptible to viral illnesses like the flu and the
common cold, as well as other infections. Stress can also increase the time it takes you to
recover from an illness or injury.
STRESS AND YOUR BODY:
Your body reacts to stress by releasing hormones. These hormones make your
brain more alert, cause your muscles to tense, and increase your pulse. In the
short term, these reactions are good because they can help you handle the
situation causing stress. This is your body's way of protecting itself.
When you have chronic stress, your body stays alert, even though there is no
danger. Over time, this puts you at risk for health problems, including:
High blood pressure
Heart disease
Diabetes
Obesity
Depression or anxiety
Skin problems, such as acne or eczema
Menstrual problems

14. 14
WHAT ARE THE SIGNS OF TOO MUCH STRESS?
Stress can cause many types of physical and emotional symptoms.
Sometimes, you may not realize these symptoms are caused by stress.
Here are some signs that stress may be affecting you:
Diarrhea or
constipation
Forgetfulness
Frequent aches
and pains
Headaches
Lack of energy
or focus
Sexual problems
Stiff jaw or neck
Tiredness
Trouble sleeping
or sleeping too
much
Upset stomach
Use of alcohol or
drugs to relax
Weight loss or
gain

15. 15
HOW TO MANAGE STRESS?
1. Exercise
Working out regularly is one of the best ways to relax your body and mind.
Plus, exercise will improve your mood. But you have
to do it often for it to pay off.
2. Relax Your Muscles
When you’re stressed, your muscles get tense. You
can help loosen them up on your own and refresh
your body by Stretching, Enjoying a massage,
Taking a hot bath or shower and Getting a good
night’s sleep.
3. Deep Breathing
Stopping and taking a few deep breaths can take the pressure off you right away. You’ll
be surprised how much better you feel once you get good at it.
4. Eat Well
Eating a regular, well-balanced diet will help you feel better in general. It may also help
control your moods. Your meals should be full of vegetables, fruit, whole grains, and
lean protein for energy. And don’t skip any. It’s not good for you and can put you in a
bad mood, which can actually increase your stress
5. Take a Break
Restful things you can do include:
Meditation
Yoga
Prayer
Listening to your favourite music
Spending time in nature
6. Make Time for Hobbies
Relaxing hobbies include things like:
Reading
Knitting
Doing an art project
Playing golf
Watching a movie
Doing puzzles
Playing cards and board games

16. 16
IS THERE A STRESS MANAGEMENT DIET?
Healthy Food Choices
Important Nutrients for Stress-Reduction
Vitamin C: Consuming foods high in vitamin C, such as
oranges and other citrus fruits, can reduce stress and
boost the immune system. Intake of this vitamin can help
lower the levels of cortisol, a stress hormone, and blood
pressure during high-anxiety situations.
Complex Carbohydrates: Complex carbohydrates, such
as whole grains, fruits, and vegetables, can induce the
brain to increase serotonin production and stabilizing
blood pressure as a way to reduce stress.
Magnesium: Obtaining an adequate amount of
magnesium is essential for avoiding headaches
and fatigue. Oral magnesium can also
successfully relieve premenstrual mood changes.
Additionally, increased magnesium intake has
been found to improve sleep quality in older
adults. Healthy sources of magnesium include
spinach or other leafy greens, salmon, and
soybeans.
Omega-3 Fatty Acids: Fatty fish (such as salmon
and tuna) and nuts and seeds (such as
flaxseeds, pistachios, walnuts, and almonds) are
rich in omega-3 fatty acids, which have been
shown to reduce surges of stress hormones and
also confer protection against heart disease,
depression, and premenstrual syndrome.

17. 17
STATISTICS ON STRESS
WORLDWIDE

18. 18

19. 19
BIBLIOGRAPHY
https://humanstress.ca/stress/what-is-stress/biology-of-stress/
https://www.helpguide.org/articles/stress/stress-symptoms-signs-and-
causes.htm/
https://medlineplus.gov/ency/article/003211.htm
https://www.stress.org/
https://www.mayoclinic.org/healthy-lifestyle/stress-management/in-
depth/stress-symptoms/art-20050987
https://www.webmd.com/balance/stress-management/stress-symptoms-
effects_of-stress-on-the-body#1
https://www.anxietycentre.com/anxiety/stress-response.shtml
https://www.medicinenet.com/stress/article.htm
https://exploreim.ucla.edu/nutrition/eat-right-drink-well-stress-less-
stress-reducing-foods-herbal-supplements-and-teas/
https://www.apa.org/news/press/releases/stress/2011/impact
https://www.who.int/