Sex can actually directly impact your immune
system, both for good and for bad sense. Sex, it turns out, is really good
for you. But, it does have its risks too.
Whilst exposure to things like sexually
transmitted diseases (STDs) is an obvious one, as we see, there are some other
more subtle changes that can take place. From priming a woman's immune system
for getting pregnant, to actually increase your likelihood of getting HIV,
sexual activity has been shown to directly affect the immune system.
Does
sexual behavior affect the immune system?
It has long been known that sex can
affect your immune system. Researchers have explained that sex can be both
beneficial and detrimental to one's immune system. The immune system boosts
from sex also has a positive impact on your sex drive and general mood. People who also
have regular sex tend to take less sick days. Researchers were able to show
that college students who had sex once or twice a week had higher levels of a
certain antibody compared to students who had sex less often. Having sex also
has many other benefits to you and your well-being.
It can:
- Lower
your blood pressure; Improve bladder control in women;
- Boost
your libido (obviously);
- Improve
your physical fitness (it is a form of exercise after all);
- Lower
your risk of heart attacks (believe it or not);
- Block
pain, or lessen pain;
- Has
been shown to reduce the likelihood of developing prostate cancer;
- Improves
your sleeping patterns; and,
- Help
reduce stress.
Can sexual behavior
affect the immune system?
One study appears to show a link between sexual activity and the
subject's ability to combat pathogens. Researchers in 2001 found that males who
had more sexual partners showed a marked reduction in the ability to fight off
a bacterial infection. Their results suggest immunosuppression
is an important cost of reproduction and that immune function and levels of
disease susceptibility will be influenced by sexual selection.
But, it is important to note that the study was concerned with male
flies of the Drosophila melanogaster (common
fruit fly) species, not human beings. But, of course, flies are not humans. This species of
fly's sexual life is very different too. In D. melanogaster there is no
paternal care, and male reproductive effort is composed entirely of investment
in successfully mating. In nature, an evolutionary increase in mating effort
will be favored by increased sexual selection.
But it's not all bad.
There are many other studies that show
sex is also beneficial to you and your immune system. It may even increase a
woman's chance of getting pregnant (if you're trying for a baby of course). The
study, by researchers showed a clear link between sexual activity and physical
changes (including the immune system) that increased the chance of conception,
even outside of the window of ovulation. It's a common recommendation that
partners trying to have a baby should engage in regular intercourse to increase
the woman's chances of getting pregnant even during so called 'non-fertile'
periods although it's unclear how this works
This research is the first to show that
the sexual activity may cause the body to promote types of immunity that
support conception. But, of course, this should come as no surprise. The more
you have unprotected sex, the higher the chance you will become pregnant (as a
woman). But what is interesting is that the human
body appears to show physical changes that appear to increase the likelihood of
conception.
Can sexual
behavior affect your gut microbiome?
Your sexual behavior can, it appears,
alter your gut microbiome. Some recent studies have shown a connection between
your sexual preference and susceptibility to infectious diseases. For clarity,
the microbiome is the community of microbes that live inside our gut. A healthy
microbiome is vital for many things including the efficiency and function of
your immune system.
One study, in particular, found that men who have sex with men
(MSM) have a distinct gut ecology compared to men who have sex with women
(MSW). Results were also not dependent on the subjects HIV-status. Their
method included taking 35 stool samples of healthy men. The donors were a
mixture of men who have sex with men and men who have sex with women. The
stool samples were then transplanted into lab mice. They found that the
stool samples from MSM showed a marked increase in the activation of CD4+ T cells within
the mice. This, it turns out, would put those mice at a higher risk of being
susceptible to HIV (if they were human). CD4+T cells "recognize peptides presented on MHC class II molecules, which are found on antigen-presenting cells (APCs). As a whole, they play a major role in
instigating and shaping adaptive immune responses.
These results provide evidence
for a direct link between microbiome composition and immune activation in
HIV-negative and HIV-positive MSM, and a rationale for investigating the gut
microbiome as a risk factor for HIV transmission. There is a unique microbiome
associated with men who have sex with men that drives immune activation in the
gut that may also drive higher levels of HIV infection. But we still don’t know
exactly why this is
Whilst the study is interesting, further investigation is
still needed to understand why the microbiome is important. If it is
responsible for weakening immune systems, especially with regards to HIV, it
may yield some fertile ground for combating the disease.
