Does sex have any "side effects"?

Having sex in addition to its health benefits can still have side effects such as sexually transmitted infections (STIs) or unwanted pregnancy. However these are preventable if you plan ahead and have all the controls in place.

Thanks to increased blood flow and heart rate with a boost of hormones and endorphins, sexual activity affects the body from head to toe. During the first sex, when the hymen is not broken, you will feel some pressure and may notice pain along with light bleeding.
In case you feel pain during sex, try using a lubricant and have sex more gently. If you've tried all of the above and it's still painful to have sex, talk to your doctor to find out the cause and he or she will find the right solutions for you. There are several factors that can cause pain during sex such as vaginismus, vaginal scarring, pelvic floor hypertonia, endometriosis, uterine fibroids, etc...
During With sexual activity, your heart rate and breathing will increase rapidly, and you may become fatigued from the exercise. The excitement of getting ready to engage in sexual activity can also cause the neck and breathing rate to increase faster. Therefore, it is normal for sexual activity to make you feel tired, but orgasm releases certain endorphins that can have a sedative effect.
When sexually active, the body can experience phenomena such as muscle tension and even lead to cramps in some parts such as hands, feet, hips and calves. Drinking enough water before sex can help reduce this risk. However, pain is sometimes also a manifestation of sex in many rough positions or without the use of lubricants.

Besides, when having sex, the body will secrete fluids such as semen to lubricate the vagina and if having anal sex, stool may appear during sex.

Emotions experienced during sexual activity depend on a range of factors, including stress levels, hydration, upbringing, culture, religion has taught you about sexual activity, pleasure, how emotionally attracted you are to your partner, what kind of intimacy are you seeking through this interaction, how secure do you feel with your partner, etc. ....
You can feel hyper connected, relaxed, satisfied or euphoric if you feel safe and respected by your partner. Conversely, you may also experience feelings of shame, guilt, or hurt if you are unknowingly under pressure from family or close friends.

After vaginal sex you may notice a change in your genital odor. Because the vagina is naturally super acidic and ejaculation changes the pH of the vagina and changes the smell for a day or two afterward. If the odor persists for more than 3 days, you should talk to your gynecologist as a change in odor could signal an infection such as bacterial vaginosis or a yeast infection. Muscles may be sore, specifically can be gluteal muscles, tendons, glutes, and arms.

Women are more susceptible to urinary tract infections (UTIs) than men because of the shorter urethral canal. To reduce the risk of UTIs, you should urinate after sex because urinating helps clear the tube of bacteria. Symptoms of a urinary tract infection include burning while urinating, a stinging or painful feeling when urinating, blood in the urine, and kidney pain.

Pregnancy is one of the possible risks when you have sex without using birth control or using birth control correctly. If you're on the Pill, be sure not to skip a pill, and if you're using another method of protection like condoms, choose one that's made of good material and is the right size.

STIs don't come on naturally, if your partner has an STI then that infection will likely be passed on to your genitals, mouth or anus depending on the type of sexual activity you engage in.
Most people with an STI don't know when they have it, because most people don't experience any symptoms. So an STI can still be transmitted even if you can't see it with the naked eye, and it can be difficult to tell if your partner and you are infected or not.
Oral, anal and vaginal sex can greatly reduce the risk of transmission. But some STIs are spread by skin-to-skin contact. The only way to know if you have an STI is to get tested. So, if your partner is STI positive or your partner doesn't know his or her current STI status, get tested 2 weeks after likely exposure.

Sex can bring you many emotions. Some of these include:
Feelings of satisfaction Feelings of jubilation Feelings of Appreciation Feelings of Power Feelings of Vulnerability Feelings of shame or embarrassment Feelings of guilt To reduce the risks that Sexual intercourse can bring, you and your partner can take some of the following measures:
Use condoms Apply birth control or preventive medicine before sex. Only have sex with a partner you feel safe with. Sexual activity is also great for the pelvic floor. Orgasms cause the pelvic floor to contract, which can help keep them healthy as you age. Sex also brings blood flow to the genitals, which helps to nourish the genital tissues. Plus, the more you engage in voluntary sexual activities, the more your body craves. So, not engaging in sexual activity can lead to a decrease in sex drive.

If you are experiencing any of the following physical changes after having sex, consult a healthcare professional:
Changes in the genitals, anus or out bleeding when you have not had a period or irregular bleeding and other symptoms such as soreness, pain or discomfort that last more than 3 days Suspect you may be pregnant Your partner has an STI or you do not know the status of the STI All of our sexual activities carry both positive and negative elements. However, you can completely control them to avoid affecting your health in the future.
Currently, Vinmec International General Hospital has developed a social disease screening package that is trusted and chosen by many people. Screening package for social diseases for all ages in both men and women. The examination helps customers to screen for social diseases in order to detect diseases early to have effective treatment and avoid complications.
The examination process is always performed by a team of qualified doctors with many years of experience. Therefore, customers can be assured of the quality of the examination as well as all personal information being absolutely confidential by the hospital.

Reference source: healthline.com