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What are the normal phases of Sexual Response ?

The sexual response cycle refers to the events of physical and emotional changes that occur as a person becomes sexually aroused and participates in sexually stimulating activities and either intercourse or and masturbation. (The steps are simplified for understanding)

Sexual Response Cycle Simplified:

The sexual response cycle has four phases:

  • Excitement
  • Plateau
  • Orgasm and
  • Resolution

Both men and women experience these phases, although the timing usually is different. Normally both partners will reach orgasm at the same time. In addition, the intensity of the response and the time spent in each phase varies from person to person. Understanding these differences may help partners better understand one another's bodies and responses, and enhance the sexual experience.

Phase 1: Excitement

General characteristics of the excitement phase, which can last from a few minutes to several hours, include the following:

  • Muscle tension increases.
  • Heart rate quickens and breathing is accelerated.
  • Skin may become flushed (blotches of redness appear on the chest and back).
  • Nipples become hardened or erect.
  • Blood flow to the genitals increases, resulting in swelling of the woman's clitoris and labia minora (inner lips), and erection of the man's penis.
  • Vaginal lubrication begins.
  • The woman's breasts become fuller and the vaginal walls begin to swell.
  • The man's testicles swell, his scrotum tightens, and he begins secreting a lubricating liquid.

Phase 2: Plateau

General characteristics of the plateau phase, which extends to the brink of orgasm, include the following:

  • The changes begun in phase 1 are intensified.
  • The vagina continues to swell from increased blood flow, and the vaginal walls turn a dark purple.
  • The woman's clitoris becomes highly sensitive (may even be painful to touch) and retracts under the clitoral hood to avoid direct stimulation from the penis.
  • The man's testicles are withdrawn up into the scrotum.
  • Breathing, heart rate, and blood pressure continue to increase.
  • Muscle spasms may begin in the feet, face, and hands.
  • Muscle tension increases.

Phase 3: Orgasm

The orgasm is the climax of the sexual response cycle. It is the shortest of the phases and generally lasts only a few seconds. General characteristics of this phase include the following:

  • Involuntary muscle contractions begin.
  • Blood pressure, heart rate, and breathing are at their highest rates, with a rapid intake of oxygen.
  • Muscles in the feet spasm.
  • There is a sudden, forceful release of sexual tension.
  • In women, the muscles of the vagina contract. The uterus also undergoes rhythmic contractions.
  • In men, rhythmic contractions of the muscles at the base of the penis result in the ejaculation of semen.
  • A rash, or "sex flush" may appear over the entire body.

Phase 4: Resolution

During Resolution, The Body Slowly Returns To Its Normal Level Of Functioning, And Swelled And Erect Body Parts Return To Their Previous Size And Color. This Phase Is Marked By A General Sense Of Well-Being, Enhanced Intimacy And, Often, Fatigue.

  • Some Women Are Capable Of A Rapid Return To The Orgasm Phase With Further Sexual Stimulation And May Experience Multiple Orgasms.
  • Men Need Recovery Time After Orgasm, Called A Refractory Period, During Which They Cannot Reach Orgasm Again.
  • The Duration Of The Refractory Period Varies Among Men And Usually Lengthens With Advancing Age.

The normal male sexual response cycle can be functionally divided into five interrelated events that occur in a defined sequence:

Libido -Libido Is Defined As The Biological Need For Sexual Activity (The Sex Drive) And Frequently is Expressed As Sex-Seeking Behavior. Its Intensity Is Variable Between Individuals As Well As Within An Individual Over A Given Time.

Erection - Erection Is The Ultimate Response To Multiple Psychogenic And Sensory Stimuli From Imaginative, Visual, Auditory (Sound), Olfactory (Smell), Gustatory (Taste), Tactile (Touch) Leading To Penile Tumescence (Filling Of Blood) And Rigidity Sufficient For Vaginal Penetration.

Further, Erection Is Associated With Significant Psychological And Physical Changes, Including Heightened Sexual Arousal

Ejaculation - This Is An Important Part Of The Sexual Response Whicg Is Under The Control Of The Nervous System And Has Two Phases-

  • Emission Where The Seminal Fluid Along With Sperm Is Deposited In The Urethra And
  • Ejaculation - In This Phase The Semen Fluid Is Ejected Out With Force

Orgasm - Heightened Sexual Excitement Feeling Again Under The Control Of The Nervous Sytem, Where An Individual Experience Ultimate Pleasure

Detumescence - During This Phase, The Penis Which Is Erect And Rigid Filled With Blood, Becomes Soft Or Flaccid As The Blood Flows Out Form The Penis And Circulation Returns To Normal.

Male Sexual Function and Aging

Males Reach Peak Sexual Capacity In The Late Teens. With Advancement Of Age, A Gradual Decrease In Sexual Responsiveness Occurs, Characterized By A Prolongation Of The Time Required To Achieve Full Erection And Decrease In The Effectiveness Of Psychic 9thought) And Tactile (Touch) Stimuli

The Plateau Phase Is Also Prolonged, And The Maintenance Of Erection Requires Continuing Direct Genital Stimulation

Orgasm And The Feeling Of Ejaculatory Inevitability Frequently Become Less Intense. Penile Detumescence Occurs More Rapidly And The Refractory Period Is More Prolonged. The Ejaculatory Volume Also Decreases With Age.

Disorders of Ejaculation

There Exists A Spectrum Of Disorders Of Ejaculation Ranging From Mild Premature To Severely Retarded Or Absent Ejaculation. Normally, By Age 17 Or 18 Yr, 75% Of Men Are Able To Control Their Ejaculation. Premature Ejaculation Is The Most Common Male Sexual Dysfunction. Several Surveys Among Different Populations Estimate Its Prevalence At 29%.

Disorders of Orgasm

Male Orgasmic Disorder Is Defined As A Persistent Or Recurrent Delay In, Or Absence Of, Orgasm After A Normal Sexual Excitement Phase During Sexual Activity. The Disorder Is Relatively Rare, Occurring In 3–10% Of Patients Presenting With Sexual Dysfunction

Failure of Detumescence

Priapism Is A Prolonged (>4 H Duration) And Extremely Painful Erection Unaccompanied By Sexual Desire And Is Often Preceded By Usual Sexual Stimuli.

Disorders of Male Sexual Dysfunction

  • Sexual Function
  • Sexual Orientation And
  • Sexual Behavior

Sex disorders of the male are classified into disorders of.

The National Institutes of Health (NIH) Consensus Development Conference advocated that "Erectile Dysfunction" ED be used instead of "impotence" to describe disorders of male sexual function and defined the new terminology as the "inability to achieve an erect penis as part of the overall multi- process of male sexual function."

Disorders of Desire is defined Hypoactive (less) Sexual Desire (HSD) as persistently or recurrently deficient (or absent) sexual fantasy and desire for sexual activity leading to marked distress or interpersonal difficulty. It is generally estimated that more than 15% of adult men and 30% of adult women have HSD. The diagnosis or identification of primary desire loss in men can only be made after ruling out the presence of factors known to affect the sexual function, which include.

  • Major Psychological Disorders
  • Chronic Medical Conditions
  • Intake Of Medications Or Substance Abuse.
  • The Most Common Causes Of Secondary Disorders Of Sexual Desire Are Of Psychogenic Origin And Androgen(Male Hormone) Deficiency

Erectile Dysfunction

This is best defined as repeated failure to generate sufficient penile body pressure (firmness) to achieve vaginal penetration and/or the inability to maintain this degree of penile rigidity until ejaculation.

How common is erectile dysfunction?

ED is a very common condition, particularly in older men. It is estimated that half of all men between 40 and 70 years of age will experience ED at least once.

ED can have a range of causes, both physical and psychological. Possible physical causes include:

  • Heart Disease,
  • Diabetes,
  • High Blood Pressure (Hypertension), And
  • Hormonal Problems

Possible psychological causes of ED include:

  • Stress
  • Anxiety
  • Depression, And
  • Relationship Problems.

To understand more about the possible causes of erectile dysfunction (ED) it is useful to know how erections occur.

When you become sexually aroused, your brain sends signals to the nerves in your penis. The nerves increase the blood flow to your penis, causing the tissue to expand and harden.

Therefore, anything that interferes with your nervous system, or the circulation of your blood, can potentially lead to ED.

Psychological factors, such as stress, or depression, can also reduce your libido (your interest in sex) making it harder for your brain to trigger an erection. Changes in hormonal levels can also affect your libido.

Physical causes of erectile dysfunction

Health conditions

There are four main types of health condition that can cause ED. These are described below.

  • Vasculogenic - Health Conditions That Can Affect The Flow Of Blood To Your Penis.
  • Neurogenic - Health Conditions That Can Affect Your Nervous System.
  • Hormonal - Health Conditions That Can Affect Your Hormone Levels.
  • Anatomical - Health Conditions That Can Affect The Physical Structure Of Your Penis.

Vasculogenic conditions

Examples of vasuclogenic conditions include:

  • Heart Disease.
  • Arteriosclerosis - Hardening Of The Arteries
  • High Blood Pressure (Hypertension), And
  • Diabetes - Which Can Affect Both The Blood Supply And The Nerve Endings In Your Penis, So It Also A Neurogenic Condition.

Neurogenic conditions

Examples of neurogenic conditions include:

  • Multiple Sclerosis,
  • Parkinson’s Disease,
  • Spinal Injury, Or Disorder, And
  • Tumours.

Anatomical conditions

Examples of anatomical conditions include:

  • Peyronie's Disease - A Condition That Affects The Tissue Of The Penis, And.
  • Hypospadias - A Congenital Condition That Causes The Urethra (The Urine Tube) To Develop Abnormally.

Medicinal causes of erectile dysfunction

In some men, a number of medicines can cause ED, including those that are listed below:

  • Diuretics - Medicines That Increase The Production Of Urine, And Are Often Used To Treat High Blood Pressure (Hypertension), Heart Failure, And Kidney Disease.
  • Antihypertensives - Medicines, Such As Beta-Blockers, That Are Used To Treat High Blood Pressure (Hypertension).
  • Fibrates - Medicines That Are Used To Lower Cholesterol Levels.
  • Antipsychotics
  • Antidepressants
  • Steroids
  • Immunosuppressants - Medicines That Are Used Suppress The Immune System.
  • H2-Antagonists - Medicines That Are Used To Treat Stomach Ulcers.
  • Anticonvulsants - Medicines That Are Used To Treat Epilepsy.
  • In some men, a number of medicines can cause ED, including those that are listed below: If you are concerned that a prescribed medication is causing ED, you should speak to your GP about it because an alternative medication may be available.

However, do not stop taking a prescribed medication without first consulting with your GP. Psychological causes of erectile dysfunction:

Possible psychological causes of ED include:

  • Depression
  • Anxiety
  • Stress, And
  • Unresolved Relationship Problems With Your Partner.

ED can often have both physical and psychological causes. For example, if you have diabetes, it may be difficult for you to get an erection, which may cause you to become anxious about the situation. The combination of diabetes and anxiety may lead to an episode of ED.

Other causes of erectile dysfunction

  • Obesity
  • Smoking
  • Alcohol
  • Tiredness, And
  • Using Illegal Drugs, Such As Cannabis, Or Cocaine.

Other possible causes of ED include: Sometimes, cycling can also be a cause of ED. People who spend more than three hours a week cycling may experience ED due to the saddle placing pressure on the nerves in their penis.


Before diagnosing erectile dysfunction (ED), your GP will ask you about your symptoms, your overall physical and mental health, your alcohol consumption, whether you take drugs, and whether you are currently taking any medication.

Your GP will also want to know whether your ED is permanent, or only occurs when you are attempting to have sex with your partner. The former suggests that there is an underlying physical cause, and the latter suggests an underlying psychological cause.

Your GP may carry out a physical examination of your penis to rule out any possible anatomical causes, such as Peyronie's disease.

Blood tests may also be used to check for possible underlying health conditions. For example, abnormal hormone levels could suggest a hormonal condition, such as an under-active thyroid (hypothyroidism), or high glucose levels could suggest diabetes.

A blood pressure test is usually carried out to check if you have high blood pressure (hypertension).

Further testing

Further testing for ED is usually only required if you are unusually young to be experiencing ED. This is because ED is relatively rare in men who are under 40 years of age.

Your GP may also recommend further testing if they think that you may have a more serious underlying health condition, such as heart disease, or arteriosclerosis. Some of these tests are outlined below.


An ultrasound scanner can be used to build up a more detailed picture of the blood vessels inside your penis.

Intracavernous injection test

An intracavernous injection test involves injecting a synthetic hormone into your penis in order to increase the blood flow to your penis. If the injection fails to produce an erection, it may indicate that there is a problem with the blood supply to your penis.


Cavernosometry involves injecting a special dye into the blood vessels of your penis. The dye is then studied on a scanner and can help show how the blood is moving through your penis, and whether there are any blockages, or abnormalities, in the blood vessels.

Nocturnal tumescence test

Most healthy men experience erections when they are sleeping, so a nocturnal tumescence test involves spending a night in hospital. During the test, a piece of perforated tape is tied to the base of your penis. If you have an erection during the night, the tape will break.

A nocturnal tumescence test is useful for determining whether ED is due to physical or psychological causes.


If you have erectile dysfunction (ED), the treatment that you will receive will depend on the underlying cause of the condition.

If ED is due to an underlying health condition, such as heart disease, or diabetes, that condition may need to be treated first before treatment for ED can begin. However, in some cases, treating the underlying cause will also resolve the problem of ED.


The symptoms of ED can often be improved by using some self-help techniques, and making associated life style changes. These include:

  • Losing Weight (If You Are Overweight)
  • Giving Up Smoking (If You Smoke)
  • Moderating Your Consumption Of Alcohol
  • Not Using Illegal Drugs, And
  • Taking Regular Exercise.

Hormone therapy

If a hormonal condition is causing ED, you may be referred to an endocrinologist. An endocrinologist is a health professional who specialises in the treatment of hormonal conditions. Many hormonal conditions can be treated using injections of synthetic hormones that help maintain normal hormone levels.