What is the sexual response cycle?
The sexual response cycle refers to the sequence of physical and emotional changes that occur as a person becomes sexually aroused and participates in sexually stimulating activities, including intercourse and masturbation. Knowing how your body responds during each phase of the cycle can enhance your relationship and help you pinpoint the cause of sexual dysfunction. There are several different proposed models of a sexual response cycle. The one that is reviewed here is one of the more commonly quoted.
What are the phases of the sexual response cycle?
The sexual response cycle has been described as having four phases:
- Desire (libido).
- Arousal (excitement).
Both men and women can experience these phases, although the timing may be different. For example, it's highly unlikely that 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. Many women won't go through the sexual phases in this order.
Some of these stages may be absent during some sexual encounters, or out of sequence in others. A desire for intimacy may be a motivation for sexual activity in some individuals. Understanding these differences may help partners better understand one another’s bodies and responses, and enhance the sexual experience.
Several physiologic changes may occur during different stages of sexual activity. Individuals may experience some, all or none of these changes.
Phase 1: Desire
General characteristics of this phase, which can last from a few minutes to several hours, and may include any of the following:
- Muscle tension increases.
- Heart rate quickens and breathing gets faster.
- Skin may become flushed (blotches of redness may 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 may begin.
- 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.
It's important to note that everyone sexual experience is different. Some may not consistently experienced the above changes. Not only can this vary between individual persons, but can also vary in an individual between different sexual encounters. Sometimes the desire phase may come after arousal.
Phase 2: Arousal
General characteristics of this phase, which extends to the brink of orgasm, include the following:
- The changes begun in the first phase get more intense.
- The vagina continues to swell from increased blood flow, and the vaginal walls turn a darker color.
- The woman’s clitoris becomes highly sensitive (may even be painful to touch).
- 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.
- Tension in the muscles increases.
Phase 3: Orgasm
This phase is the climax of the sexual response cycle. It's 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 may also undergo 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 this phase, 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 in some by a general sense of well-being 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 typically need recovery time after orgasm, called a refractory period, during which they cannot reach orgasm again. The duration of the refractory period varies among individuals and changes with age.