# RKS: ADRENALINE DRIVE - Influence Of Aging

  

# RKS: ADRENALINE DRIVE 

INFLUENCE OF AGING

RKS / 2024-2025 / Ser 6 / Blog 1

1st October 2024

ALL ABOUT ADRENALINE

ADRENALINE RUSH vs DRIVE

Dear Reader,

Adrenaline, also referred in American textbooks as epinephrine, is a hormone which is secreted by two adrenal glands. These glands are also referred to as suprarenal glands since they reside above each of the two kidneys. Exciting, dangerous and stressful situations lead to secretion of adrenaline.

Fig: Adrenal glands location.

The adrenaline drive is all about risk-taking and thrill-seeking behaviour of an individual. Aging leads to a decline in the manufacturing of adrenaline. It would therefore be interesting to understand how adrenaline dictates one's personality and personifies an individual's behaviour and attitude especially when it pertains risk-taking ability and decisions.

SYMPATHOADRENAL SYSTEM

The 3 parts of the nervous system are:

1. Brain protected by skull
2. Spinal cord covered within the backbone
3. Nerves present all over the body

Given these operational organs and extensions, the nervous system is functionally divisible as:

• Higher functions: Thinking, memory, learning, emotions, analyzing & decision-making as well as visuo-spatial processing [interpreting messages relayed as light waves & sound waves, sensations (from nose, tongue & skin)] - all these are labelled as cognitive functions of brain.
• Messages relaying to and from brain: Nerves are the information transmitting connections in the body.
• Special senses: Eyes for seeing, ears for hearing, nose for smelling, tongue for tasting and skin for experiencing various sensations such as touch, pain, etc.

There are accordingly 3 nervous systems operational in the body:

1. Central Nervous System (CNS): The brain and spinal cord constitute the CNS. All the higher functions are the function of the brain. The special senses present in head - including the skin of the face, are all controlled by nerves – called cranial nerves (total of 10 present) directly connected to the brain (only).
2. Peripheral Nervous System (PNS): All the sensations from the neck below regions are directly relayed to nerves connected to the spinal cord. In addition, the PNS also sends command to all voluntary muscles in the upper (upper arm, forearm, hands) and lower (thigh, leg, foot) limbs to either contract or relax.
3. Autonomic Nervous System (ANS): This is a separate system which has autonomous functioning and controls all the organs within the chest cavity (thorax) as well as in tummy (abdomen). There are 5 systems present in these hollow parts of the body namely, respiratory, cardiovascular, digestive, urinary and genital organs.

The ANS controls the involuntary muscles of the mentioned five systems and is further subdivided into 2 parts:

1. SYMPATHETIC NERVOUS SYSTEM: Operates similar as a car gas pedal.
2. PARASYMPATHETIC NERVOUS SYSTEM: Works akin to a car brake.

The rate of heart beating, breaths per minute, frequency of passing motions and urine are all increased by sympathetic nervous system (like pressing the vehicle accelerator) whilst parasympathetic nerves originating from brain slow down (just like braking system) each of these activities of the body organs. The dual control of respiratory, cardiovascular, digestive and urinary organs ensure a balanced normal beating of heart at the rate of 75 per minute (average), 16-18 breathes per minute, etc.

Controlling muscles and relaying of messages within brain and spinal cord can only be possible via special chemicals called neurotransmitters which provide the interface between two nerves or between the nerve and the nerve cell (neurone).

 

NEUROTRANSMITTERS

The messages in nerves traverse as electrical current. However, between two nerves, and between a nerve a neurone there are gaps (referred to as synapse). As no electricity can be passed from any wire to another end of a wire when the same is cut the same is applicable for electrical messaging via synapses. Thus, there are neurotransmitters present in the gaps in-between nerves to facilitate the electrically-communicated message to be conveyed further.

Fig: Synapse.

The neurotransmitters for the nervous systems are:

• BRAIN: There are over 60 neurotransmitters in brain but the most important ones include noradrenaline (NA) [also called norepinephrine (NE)], serotonin (5-HT) and dopamine.
• PNS: The main neurotransmitter is acetylcholine (Ach).
• ANS: the neurotransmitter for the sympathetic nervous system is NA whilst for the parasympathetic it is Ach. 

The NA, 5-HT and dopamine (in brain) have distinct roles to play and the following diagram also depicts the combined action of any 2 or even all three of these neurotransmitters.

Diagram: Actions of individual transmitter and combined - since various permutations exist in different regions of brain.

The Ach has dual role to play:

• In PNS, Ach liberation results in contraction of muscles (voluntary muscles of limbs) and also facilitates more secretion by sweat glands. 
• In parasympathetic nervous system, Ach release causes contraction of involuntary muscles of heart, airways passages as well as digestive and urinary tracts - besides influencing secretion of glands present in these organs and systems.

Ach additionally stimulates the inner medulla part of adrenal glands to facilitate liberation of two important hormones - adrenaline and NA, which are collectively referred to as catecholamines. 

Fig: Parts of adrenal glands.

The difference between the two catecholamines is that NA is secreted by nerve endings of sympathetic nerves regulating the 4 systems present in chest and abdominal cavities, whilst adrenaline circulates in blood. NA is continuously secreted but adrenaline is released only during a fight-flight response (also called the fight, flight, or freeze response) to combat stress. 

STRESS & RESPONSES

Any physical or psychological stimuli that disrupt homeostasis result in a stress response. The stimuli are called stressors, and physiological and behavioral changes in response to exposure to stressors constitute the stress response.

Stress generally affects all body systems, including cardiovascular, respiratory, endocrine, gastrointestinal, nervous, muscular and reproductive systems.

TYPES & NATURE OF STRESSES

Stresses can be:

1. Distress - when stress causes adverse effects on mind and body.
2. Eustress - when the stress is enjoyable, stimulating and inspiring.

Types of stress are:

1. Acute stress: This is a short-term stress that typically results from immediate stressors or challenging situations.
2. Chronic stress: This occurs when the stressor persists over an extended period and can precipitate cardiovascular disease, anxiety and depression.
3. Episodic acute stress: The stress occurs when individuals experience frequent episodes of acute stress. This pattern may be characteristic of individuals who lead chaotic or disorganized lifestyles, constantly facing deadlines, commitments, or interpersonal conflicts.

Stress can be categorized depending on the cause:

• Traumatic stress: This type results from exposure to traumatic events, such as natural disasters, accidents or violent acts. It may lead to symptoms of posttraumatic stress disorder (PTSD), including intrusive memories, avoidance behaviors and hyperarousal.
• Environmental stress: This type arises from adverse or challenging conditions in one's surroundings, including noise, pollution, overcrowding, or unsafe living conditions.
• Psychological stress: The stress stems from cognitive or emotional factors, such as perceived threats, worries or negative thoughts. Typical stressors include work-related pressures, academic expectations, social comparisons or self-imposed demands.
• Physiological stress: Illnesses, injury, sleep deprivation or nutritional deficiencies activate physiological stress pathways and compromise health and well-being.

CONSEQUENCES OF STRESS

General adaptation syndrome (GAS) describes the physiologic changes your body goes through as it responds to stress. These changes occur in stages:

1. An alarm reaction – fight-or-flight response.
2. A resistance phase – during which the body recovers and manifestations of fight-or-flight response reverse back to normalcy in terms of heart rate and breathing intensity.
3. A period of exhaustion.

The endocrine system increases the production of steroid hormones, including cortisol, to activate the body's stress response. In the nervous system, stress triggers the sympathetic nervous system, prompting the adrenal glands to release catecholamines – fight-or-flight response. Once the acute stress-induced crisis subsides, the parasympathetic nervous system aids in the body's recovery – resistance phase.

With regards to period of exhaustion, enduring stressors without relief drains the physical, emotional and mental resources of body to the point where one is no longer able to cope with stress. The same is manifested as fatigue, burnout or mere decreased stress tolerance.

FIGHT-OR-FLIGHT RESPONSE

The fight-or-flight state is a physiological reaction that prepares our bodies to stay and fight or to flee. The whole process is actually segregated as:

1. Fight
2. Flight
3. Freeze
4. Fawn

The fight-or-flight response originated in the ancestors who when confronted by wild animals in a jungle classically exhibited either of the reaction. Freeze and fawn are responses that do not involve decisive actions and are typical of those who can neither fight nor flee. The response of an individual - whether it is fight or flight or freeze or fawn is dependent on the catecholamines. 

FIGHT

When one's body feels that it is in danger and believes it can overpower the threat, the response will be fight mode. The signs of putting up a fight include:

• Tight jaw
• Grinding of teeth
• Urge to punch something or someone
• A feeling of intense anger 
• Need to stomp or kick
• Crying in anger
• A burning or knotted sensation in stomach
• Attacking the source of danger

All the above are consequences of signals released by brain to prepare for the fight.

FLIGHT

If the body believes that the danger cannot be overcome but it can avoided by running away, the response will be the flight mode. Signs of flight response include:

• Excessive exercising
• Feeling fidgety, tense, or trapped
• Constantly moving the legs, feet, and arms
• Restless body
• Feeling of numbness in arms and legs
• Dilated, darting eyes

The responses preceding the flight mode are also the result of action of catecholamines.

FREEZE

This stress response causes you to feel stuck in place and the signs of freeze include:

• Sense of dread
• Pale skin
• Feeling stiff, heavy, cold and numb
• Loud, pounding heart
• Decreasing heart rate

5-HT is the neurotransmitter in brain which inhibits the fight-or-flight response initiated by the amygdala (situated in the brain).

Fig: Amygdala in brain.

The amygdala is a small, almond-shaped part present in the temporal lobe of the brain that plays a key role in processing emotions (especially FEAR), memory and social stimuli. 

Any stress which precipitates either the fight or flight response is the outcome of processing the same emotionally by the amygdala.

FAWN

This response is used after an unsuccessful fight, flight or freeze attempt. 

• Over-agreement
• Trying to be overly helpful
• Primary concern with making someone else happy
• Offering praise and admiration, even when criticized 
• Having little to no boundaries 
• Being easily controlled and manipulated

The fawn response occurs primarily in people who grew up in abusive families or situations. 

ROLE OF NEUROTRANSMITTERS IN FIGHT-OR-FLIGHT RESPONSE

The eyes and ears on sensing danger send the signals to the amygdala for processing. When the signal processed indicates danger, the amygdala then conveys the response to the hypothalamus which in turn activates the parasympathetic nerves to release Ach in adrenal glands and facilitate liberation of the two catecholamines – sympathetic-adreno-medullary (SAM) axis.

Afterwards, the hypothalamus communicates with the pituitary gland in brain and the latter liberates adrenocorticotrophic hormone (ACTH) which stimulates the adrenal glands to secrete cortisol (a corticosteroid hormone). This interlinking of hypothalamus - pituitary - adrenals is called as HPA axis. Thus, cortisol is released at the later stage in the fight-or-flight response.

FIGHT-OR-FLIGHT

In the fight-or-flight response the sympathetic drive increases the secretion of both adrenaline as well as NA. Usually NA is continuously produced in brain as well as by adrenals and keeps one ever-vigilant via its effect in brain as a neurotransmitter. Throughout the day the various exciting and heart-throbbing incidences and instances precipitate adrenaline release daily from the adrenal glands and this measures 150 mcg – this maintains a basal adrenaline blood level of 25-50 pq/mL. More adrenaline is released from the adrenal medulla than NA and this secretion of adrenaline is excessive whenever there is a looming danger.

It is adrenaline as well as NA that are responsible for making one angry, irritated and rageful in the fight mode, as well as worried, anxious and terrified in the flight mode. Besides, both these hormones also precipitate higher heart and breathing rates whilst relegating the digestive function as well as sexual arousal to the back burner.

FREEZE & FAWN

The parasympathetic system actually starts as a single nerve originating from the brain which is called as 'vagus' - cranial nerve No. X. Vagus is the longest cranial nerve since it goes all the way down to the chest and abdomen - supplying parasympathetic nerve fibres to control the 5 mentioned systems present sin these two cavities of the body.

The vagus nerve is functionally divided into 2 portions:

1. Ventral Vagal System: Constitutes the 'social engagement system' which is a hybrid state of activation and calming that plays a role in our ability to socially engage.
2. Dorsal Vagal System: Supports immobilisation behaviours, both "rest and digest" and defensive immobilisation or "shutdown".

The above separation is as per the proposed 'Polyvagal Theory' (PVT) of Stephen Porges (US) in 1994 - world-renowned researcher and Unyte Health's Chief Scientific Advisor. Whichever be the 'system' activated as per PVT, the neurotransmitter responsible will be Ach for both.

FREEZE

The freeze response is a hybrid between sympathetic mode and dorsal vagal activation. Hence, during the ‘freeze’, the body is activated by both sympathetic as well as by the dorsal vagal mode. While fear is still a driving emotion, the desire to run or fight is overshadowed by a sense of immobilization coming from dorsal vagal activation. It can be somewhat confusing when one notices someone in freeze mode because their lack of outward aggression or anxiety may lead any observer to believe that the concerned individual (in ‘freeze’ mode) is calm, when in fact, he / she is simply just numb.

FAWN

In fawn mode, the individual is immediately acting to try to avoid any conflict. When the fawn response is activated, the concerned person has exited sympathetic mode and entered complete dorsal vagal shutdown. The individual in fawn mode is no longer looking for ways to survive (fight or flight) and instead enters a state of physical and emotional collapse. 

ADRENALINE RUSH & DRIVE

The stresses in life can precipitate either an anxiety attack or an adrenaline rush.

1. ANXIETY ATTACK: An anxiety attack is a feeling of overwhelming apprehension, worry, distress or fear. For many people, an anxiety attack builds slowly. It may worsen as a stressful event approaches. Anxiety attacks can vary greatly and symptoms may differ amongst different individuals. The symptoms of an anxiety attack include dry mouth, sweating, hot flashes, palpitations, numbness and fear. 
2. ADRENALINE RUSH: When adrenaline is released in response to a stressful, exciting, dangerous or threatening situation it is called as ‘adrenaline rush’. 

During the anxiety attack there is contribution by both adrenaline as well as cortisol (corticosteroid hormone) - also manufactured by adrenal glands. In the fight-or-flight response, there is initial liberation of adrenaline and this is subsequently followed by cortisol secretion from the adrenals. Whilst adrenaline is responsible for the manifestations of fight as well as flight reactions, cortisol role is assisting healing of tissues by making available glucose and other substances.

SYMPTOMS OF ADRENALINE RUSH

The symptoms of adrenaline rush are same as those manifested during the fight-or-flight response. 

• Heart rate: Faster heart rate
• Breathing: Faster or shallow breathing
• Blood pressure: Increased blood pressure
• Alertness: Increased alertness or heightened awareness
• Pupils: Dilated pupils
Sweating: Increased sweating
Pain: Reduced pain or decreased ability to feel pain
Strength: Increased strength and performance
Senses: Heightened senses
Digestion: Slowed digestion

These symptoms are manifested within minutes of the stress experienced and the body will calm down 20-30 minutes after the stressor is removed; however, the levels of adrenaline will take a longer time to become normal (0-900 pg/mL).

CAUSES OF ADRENALINE RUSH

• Dangerous sports
• Extreme sports
• Panic attacks
• Traffic accidents
• Frightening experiences
• Watching horror movies

ADRENALINE DRIVE & AGING

Adrenaline rush is the sudden release of this catecholamine during a stressful situation. However, adrenaline drive is a feeling of excitement and physical ability that occurs when the body releases a large amount of adrenaline in response to stress. How does aging impact the adrenaline drive?

Each of the adrenal gland weighing 5 gms has 2 parts:

1. Outer cortex: Constitutes 72% of the adrenal glands and manufactures cortisol, minerals balancing (mineralocorticoids) and sex hormones.
2. Inner medulla: Balance 28% from where the catecholamines are released.

The medulla has 80-90% adrenaline secreting cells and only 10-20% NA producing cells. In the elderly, the NA concentrations in synapses never decline because it is also produced in brain. However, the adrenaline production capacity declines by about 40%! Hence, in any challenging situation eliciting a fight-or-flight situation the reaction of the elderly is compromised. 

Thus, in dangerous sporting activities like rock climbing, free fall, edge walking, snowboarding, zip lining, B.A.S.E. jumping (falling off from an object with a parachute), bungee jumping, running of the bulls, cage of death, BMX (Bicycle Motocross – type of bicycle designed for off-roading and trick riding) racing, etc. the diminished adrenaline drive doesn't excite the elderly enough to accept the challenge by fighting the fear of a daunting task.

However, the rate at which adrenal senescence occurs varies between every individual and is influenced by ones environment, lifestyle and genes.

CONCLUSIONS

When one feels safe and calm, and there is no threat in sight, the ANS goes into parasympathetic mode. In parasympathetic mode, the heart rate slows down, breathing becomes deep and relaxed, digestion is engaged, and the sexual response is more active. This is a time to relax and enjoy what life has to offer. 

Stress is a risk factor that affects the physical, mental and social health of individuals through lifespan. Stress engages the sympathetic mode is engaged and one enters what is known as the "fight-or-flight” response.

Frailty is associated with an increased vulnerability to stressful stimuli, with a decreased ability to maintain a controlled, normal response to intrinsic and environmental stressors, and decreased ability to maintain both physiological and behavioral homeostasis. Almost 20–30% of the population over 75 years of age is associated with geriatric frailty, which increases notably with advancing age. The chief reason is the diminished adrenaline rush which impairs the adrenaline drive and an ability to manifest fight-or-flight response adequately. 

Old age, however, is not always synonymous with an inability to fight-or-flight or frailty. The rate at which adrenal senescence occurs varies between every individual and is influenced by ones environment, lifestyle and genes

For the diminished adrenaline drive is to be combated there are grounding techniques available to address the same. Grounding techniques are a set of practices that can help one feel more centered and balanced when feeling overwhelmed or anxious. Grounding techniques can help reconnect with the present moment and disconnect from upsetting memories or emotions.

Diagram: Grounding techniques.

Humans straight-up need adrenaline. It’s there for everyone in every stressful situation (yup – that includes skydiving!), driving one’s decision-making with the “fight-or-flight” response and preparing the body to act or react. It’s only through evolution and progress in how one lives that the power of adrenaline for fun as well as survival can be harnessed.

The brain and body benefits from the adrenaline-induced super powers and the adrenaline does matter and also dictates undertaking the recreational high.

For increasing the adrenaline drive one needs to enhance the adrenaline rush on a regular basis –

• Engage in moderate-to-high-intensity workouts.

• Try taking the stairs.

• Strike a power pose.

• Breathing low instead of deep.

• Watch horror movies.

• Performing exciting sex.

DR R K SANGHAVI

Prophesied Enabler

Experience & Expertise: Clinician & Healthcare Industry Adviser

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