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UCLA Study Finds Cycling Might Affect Male Reproductive Health

LOS ANGELES (CBS) — A new study says male cyclists may experience hormonal imbalances that could affect their reproductive health.

A study from the UCLA School of Nursing found that serious male cyclists had elevated levels of estradiol, which is associated with conditions like loss of male pubic hair and enlarged breast tissue.

Researchers studied 107 healthy male athletes ages 18 to 60 and separated them into three groups: 16 triathletes, 46 cyclists and 45 recreational athletes. After they participated in different levels of activity and inactivity, researchers collected blood samples from each man to measure their hormone levels.

"Plasma estradiol and testosterone levels were significantly elevated in serious leisure male cyclists, a finding not previously reported in any type of male athlete," the study's senior author, Leah Fitzgerald, said in a statement.

Plasma estradiol concentrations were more than two times higher in cyclists than in the triathletes and recreational athletes, according to the study. The cyclists total testosterone levels were about 50 percent higher in cyclists than recreational athletes.

The increase of hormones could be due to the cyclists' use of chamois cream. Some cyclists apply chamois cream to their perineum area to help prevent chafing and bacterial infections related to saddle sores.

The study found an association between an increase in estrogen levels and increasing years of chamois cream use, especially for more than four years, but researchers say there's no direct cause and effect just yet.

The UCLA study, "Reproductive Hormones and Interleukin-6 in Serious Leisure Male Athletes," was published in the European Journal of Applied Physiology.

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