A man's ability to produce sperm may depend on his ability
to handle stress, according to a new study from Italy. Researchers found that
men with higher levels of both short- and long-term stress and anxiety
ejaculated less semen and had lower sperm concentration and counts.
Men with the highest anxiety levels were also more likely to
have sperm that were deformed or less mobile. But one fertility researcher not
involved in the new work said it's hard to know how the results apply to the
general population because the research included men who were already seeking
treatment at a fertility clinic.
"Do you become stressed from becoming infertile or is
stress causing infertility?" asked Tina Jensen from Rigshospitalet in
Copenhagen, who has studied the effects of environmental factors on sperm
What previous studies
Previous research has found that men going through fertility
treatment or evaluation have higher stress levels than the average person, and
some studies have also shown links between stress and sperm quality, according
to the Italian researchers, led by Elisa Vellani of the European Hospital in
But no one had looked at whether short increases in a man's
stress and long-term anxiety had differing effects, Vellani and her colleagues
write in the journal Fertility and Sterility.
For the new study, the team recruited 94 men who were
visiting the hospital's fertility clinic for the first time, and 85 other men
who were not seeking fertility treatments as a comparison group.
Each man provided a semen sample for analysis. The men then
answered two surveys that measured their current stress and long-term anxiety
on scales ranging from 20 to 80 points, with higher scores indicating greater
stress or anxiety.
How the study was
On average, men in both groups scored between 37 and 40 on
the tests, which is not considered "pathological," the researchers
note. When Vellani's group compared the 28 men with the lowest stress and
anxiety levels to the 40 men with the highest levels, however, they found the
stressed men were more likely to have lower sperm concentration and counts.
The most stressed men's sperm we also more likely to be
immobile and slightly more prone to DNA breaks."Taken together, our
observations strongly suggest that (stress and anxiety) may represent a
significant factor involved in male fertility," wrote the researchers, who
did not respond to requests for comment.
They note in their report, however, that the association
between stress and sperm quality was weaker in men who were not seeking
fertility treatment, and who also seemed to have better sperm quality anyway.
For example, men seeking fertility treatment produced about
29 million sperm per milliliter of semen, compared to approximately 52 million
sperm per milliliter produced by the men in the comparison group.
15 million sperm per milliliter is considered normal.
By the World Health Organisation's standards, anything above
15 million sperm per milliliter is considered normal. Vellani and colleagues
conclude that "social and psychological factors" should be considered
when assessing possible causes of infertility and addressed as part of
Jensen said that it's hard to tell how different the most
and least stressed men were based on the study report, but agreed that the
results are probably most relevant to men who are going through fertility
treatment, which she said is itself very stressful."Generally, for normal
men it's not important," Jensen said.