Many have heard of the "rule of 9" to calculate sexual frequency by age, which involves multiplying the tens digit of one's age by 9. For example, for age 20, it's 2 x 9 = 18, interpreted as 8 times a week; for age 30, it's 3 x 9 = 27, meaning 7 times every two weeks; and for age 40, it's 4 x 9 = 36, or 6 times every three weeks. This calculation is catchy, easy to remember, and often passed around as a "standard of performance" for men.

However, according to Dr. Tra Anh Duy, a specialist at the Men's Health Center, considering this a medical standard is inaccurate. While age does influence sex life, it is not the only determining factor. Sexual frequency often decreases with age due to hormonal changes, cardiovascular health, sleep quality, underlying health conditions, current medications, stress levels, and relationship quality.

"It's not true that younger individuals always have high libidos, and older individuals always have significantly reduced ones," the doctor stated. He offered an example: a 35-year-old man who frequently stays up late, experiences work pressure, and drinks a lot of alcohol might have less desire than a 50-year-old who gets adequate sleep, exercises regularly, and maintains a stable mental state.

Research by Twenge and colleagues, published in Archives of Sexual Behavior, indicates that sexual frequency among American adults tends to decrease with age. After peaking around age 25, the average number of sexual encounters declines by about 3.2% annually. However, this finding only reflects a general trend and cannot be applied as a fixed formula for every individual.

According to Dr. Duy, the "rule of 9" should only be viewed as a fun reference. This formula fails to account for numerous factors that directly impact male physiology, such as testosterone levels, erectile dysfunction, diabetes, hypertension, depression, medication side effects, fatigue levels, or a partner's satisfaction.

"The human body doesn't operate on a multiplication table," the doctor emphasized. "It's not a requirement for a 30-year-old to achieve 7 times every two weeks or a 50-year-old to achieve 5 times every four weeks. Sex life should not become a scheduling problem or the pressure to meet targets or bedroom KPIs."

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So, what constitutes a reasonable frequency? According to andrology experts, there is no universal number for all couples. The crucial aspect is that both partners feel comfortable, willing, free from pain, not overly exhausted, and that it does not negatively impact their health or work.

Some individuals maintain sexual activity several times a week and find it suitable, while others engage less frequently but remain satisfied. The quality of the relationship, emotional connection, and intimacy are often more important than counting the number of times.

Another study by Ueda and colleagues, published in 2020 in JAMA Network Open, noted that the percentage of American men aged 18-24 who reported no sexual activity in the preceding year increased from 18.9% to 30.9% between 2000 and 2018. This suggests that sexual frequency is also influenced by lifestyle, occupation, relationship status, and social context, not solely age.

Dr. Duy advises men to seek medical consultation if they experience prolonged low libido, difficulty achieving or maintaining an erection, abnormal ejaculation, pain during intercourse, persistent fatigue, loss of morning erections, or if a couple hoping to conceive has not become pregnant after 6-12 months. In such cases, a doctor can assess hormone levels, cardiovascular health, metabolism, psychological factors, and sperm quality to identify the underlying cause.

Le Phuong