The document discusses stress, aging, and the autonomic nervous system. It notes that chronic stress can be associated with depression and health issues. As people age, the autonomic nervous system declines progressively due to loss of neurons and neurotransmitters. Testing of autonomic functions includes evaluating blood pressure and heart rate in response to posture changes, breathing, and tasks like handgrips. A study found age-related declines in sympathetic and parasympathetic responses. Regular exercise and meditation may help delay some effects of aging on the autonomic nervous system.

1. Stress, Ageing and Autonomic
Nervous System
Satish Kalra

2. Stress and Autonomic Nervous
System
• Stress is the state of threatened homeostasis that emerges on
exposure to adverse forces.
• Acute Stress: It is the stress that persists for minutes or hours.
• Chronic Stress: It is the stress that persists for days, weeks, or
months
• Stress is associated with depression which in association with
disruption of the immune system is associated with ailments like
heart disease, type 2 diabetes, autoimmune diseases and cancer.
• Major depressive disorder (MDD) is a chronic illness characterized
by frequent relapses, incomplete recovery and residual symptoms.
It is projected to become the leading cause of disease burden
worldwide by 2030.
• Stressors activate the hypothalamic-pituitary-adrenal axis (HPA)
which is pacemaker of the autonomic nervous system (ANS) and
CNS ageing.

3. Ageing and Autonomic Nervous
System
• Progressive age-related decline in the autonomic nervous system. is
attributed to
• Loss of brain neurons and dendrites
• Decrease in number of axons in brain and spinal cord
• Decreased myelination of axons
• Increase in pigment in selected brain regions
• Decline in many neurotransmitters; there is 40% loss of receptors from
age 60 to 90
• decrease in neuronal RNA
• Additional changes in peripheral compartments of ANS are as under:
• Alterations and/or loss of sensory receptors as well as of motor effectors
in target organs
• Loss of neurons in mesenteric ganglia and various plexuses
• Decreased rate of blood flow to visceral organs owing to a decline in
cardiovascular and skeleto-muscular changes

4. Introduction to Nervous System
The nervous system is the master controller of the human body and
helps coordinate body activities and ensures homeostasis; it
communicates though neurons.
Its general functions are as under:
• Detects changes through sensory receptors: Sensory receptors
detect a range of stimuli like temperature, light, sound, chemicals in
food and air, pressure, pain, blood pH, bladder distension etc;
human body transforms stimuli into electric signals to enable
nervous system to process them.
• Transmits electrical signals to the central nervous system along
axons.
• Transmits the information to specific areas of the brain
• Sends commands to the target tissues like muscles and glands to
produce the response

5. Divisions of the Nervous System

6. Place of Autonomic Nervous System
(ANS) in the Nervous System (NS)
Central Nervous System (CNS) serves as the main control centers for all body
activities. It consists of the brain and the spinal cord.
Peripheral Nervous System (PNS) consists of nerves that link the body with CNS; 12
pairs of nerves emerge from brain and 31 pairs from spinal cord.
PNS has two subdivisions
Sensory nerves are the input nerves and send nerve impulse from the body to CNS
Motor nerves are the output nerves
Motor nerves consists of two systems
Somatic nervous system regulates the voluntary contraction of the skeletal muscles
Autonomic nervous system (ANS) regulates the involuntary control of smooth and cardiac
muscles, and glands; it is also called the visceral nervous system
ANS is also called the visceral nervous system because it controls smooth muscle,
cardiac muscle, and glands, that make up the viscera of the body; it too has two
branches - sympathetic nervous system (SNS) and parasympathetic nervous system
(PNS)

7. Place of ANS in NS
Pictorial Representation

8. Characteristics of ANS
• It works through two neuron chain; preganglionic neurons originate in CNS;
postganglionic neurons originate in the ganglion located outside the CNS; ganglia
are located within a few cm of CNS, along the vertebral column
• SNS nerves Its nerves originate from the thoracic and lumbar region of the spinal
cord
• PNS nerves originate from the CNS (brain stem) and sacral region of spinal cord
• Sympathetic Nervous System (flight– or– fight)
• Activated in emergencies, and enables the body to flee quickly flee or "take a
stand“
• Stimulates activities of the organs except digestive organs
• Parasympathetic Nervous System
• Inhibits activities of the organs except digestive organs
• Pregarglionic fibers arise from the CNS (brain stem) and sacral region of spinal cord
• Postganglionic fibers are confined to the head and viscera of chest, abdomen and
pelvis

9. Anatomical Location of PNS and SNS

10. SNS and PNS do opposite things in the
body
While the SNS prepares the body for physical and mental
activity, the PNS is responsible for bodily functions at rest.
Sympathetic nervous system
• Makes heart beat faster and stronger
• Opens airways to ease breathing
• Inhibits digestion.
Parasympathetic nervous system
• Slows the heart an, dilates blood vessels
• Decreases pupil size
• Increases digestive juices, relaxes muscles in
the gastrointestinal tract and stimulates digestion
• Activates various metabolic processes and helps us to relax

11. SNS and PNS functions – Pictorial
representation

12. Ailments of ANS
• Achalasia: Caused by fibrosis of the esophagus; the
gastro-esophageal sphincter does not relax when
swallowing; vomiting may occur
• Atonic Bladder: Urinary bladder becomes flaccid and
overfills and allows urine to dribble out; results from
loss of autonomic innervations following a spinal cord
injury
• Horner’s Syndrome: Caused by the destruction of the
superior sympathetic trunk on one side of the body, it
causes drooping of upper eyelids (ptosis) , constriction
of the pupils and loss of sweating on affected side of
head

13. Ailments of ANS
• Hypertension: Result from an overactive sympathetic
NS promoted by high stress levels
• Mass Reflex Action: It is epilepsy of the spinal cord
caused by uncontrolled activation of autonomic and
somatic motor neurons. It occurs in cases of
quadriplegia and spinal cord injuries. There is a surge
of nerve output from larger regions of the spinal cord.
• Raynaud’s Disease: Skin of fingers becomes pale, then
cyanotic and painful. It can be provoked by exposure to
cold. It is often called an exaggerated vasoconstriction
effect.

14. Autonomic testing tools
• Adrenergic: Blood pressure response to
isometric hand grip test, immediate standing
& blood pressure response to valsalva
maneuvere)
• Sudomotor: Bedside clinical method i.e. spoon
test
• Cardio-vagal: heart response to standing, deep
breathing & Valsalva manoeuvre-

15. Cardio-vagal testing
• HR variation (HRV) with deep breathing: Subjects asked to breathe deeply and evenly at 6
breaths/min in supine position; ECG recorded during the procedure and the mean difference of the
maximum-minimum HR calculated.
• HR response to Valsalva manoeuvre: Subjects asked to strain for at least 15 s; ECG recorded during
the procedure and for the following 60s; Valsalva ratio during straining as the ratio between longest
mean RR intervals to the shortest mean RR interval.
• The 30:15 ratio of HR response to standing: Subjects made to stand up as immediately as possible
after lying down for 5-7 minutes; ECG was recorded immediately and continued over a period of 60
s; 30:15 ratios is the mean ratio between the RR interval of 30th beat and the l5th beat
• Blood pressure response to standing: Subjects made to stand from lying position after relaxation of
5 minutes; B.P was measured immediately after the patient stood up and at 1, 2 and 3 min intervals
thereafter; systolic & diastolic reading at rest and after standing measured.
• Isometric Handgrip Test (HGT): Subjects asked to perform isometric exercise by pressing the
handgrip dynamometer at 30% of maximum voluntary contraction for 2 minutes. Blood pressure
recorded simultaneously from non-exercising arm at 1st and 2nd minute and measured after
releasing of grip and recording was continued till 4th minute. Highest increase in diastolic blood
pressure taken as test response.

16. Sudomotor functions
• Assessed clinically by Bed side spoon Test at
normal room temperature and humidity
• Kitchen soup spoon placed on skin with its
curved portion and drawn slowly without
lifting up and measured its flow whether
interrupted, smooth or slightly un interrupted
that measures degree of moistness of skin.

17. Meerut Studies
• Study was conducted in 62 healthy volunteers in Department of
Physiology LLRM Medical College Meerut, India
• Volunteers divided into three groups as younger (15-45 years),
middle (45-60) and elder age (above 60)
• Mean pulse rate was higher in elderly
• Mean levels of blood pressure response in terms of HGT (Hand Grip
Test) and OHT (Orthostatic Hypotension Test) increases as age
advances; this change reflects decline in sympathetic response
• Mean levels of parasympathetic response in terms of DBT, Valsalva
and 30:15 ratio decreases as age advances
• Sudomotor function was slightly interrupted in more than one third
of elderly patients.

18. Meerut Studies conclusions
• Appearance of many geriatric complaints can be slowed down by
decline in sympathetic status
• Regular meditation and aerobic exercise may be a tool to arrest the
persistent decrease in sympathetic status with age.
• Peoples doing regular meditation like different types of yoga asana
or any other type of meditation show delayed appearance of
geriatric symptoms like orthostatic hypotension, constipation etc.
• In older humans, aerobic exercises lowers heart rate at rest and
improve left ventricular performance during peak exercise.
• Subjects having better autonomic control have decreased incidence
of cardiovascular chronic diseases like hypertension, angina etc. and
also emergencies like stroke, myocardial infarction etc.