New study finds the benefits of exercise are nullified by mercury exposure

Thursday, September 29, 2016 by: Vicki Batts
Tags: mercury exposure, exercise, health benefits

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(NaturalNews) A new study has revealed that while aerobic exercise has enormous brain benefits, mercury exposure may preclude some people from experiencing them. The research, funded by the National Institute of Environmental Health Sciences (NIEHS), part of the National Institutes of Health, suggests that people who are exposed to mercury before birth do not get the same brain benefits from exercise. The study is the first of its kind to explore what the effects of prenatal mercury exposure may have even into adulthood.

Most prenatal exposure to methylmercury comes from a mother's consumption of fish that is contaminated with mercury. The study found that adults who had high levels of mercury exposure prior to birth did not gain the faster cognitive processing and better short term memory benefits of aerobic exercise. These benefits were seen in individuals with low prenatal mercury exposure, however.

The negative effects of mercury exposure have long been a subject of concern. Even small amounts of mercury can produce lasting damage. The EPA estimates that at least 75,000 babies born each year have an increased risk of having a learning disability, thanks to mercury.

Mercury accrues in the environment by way of industrial pollution. First it enters the air, and then it falls to the ground where it ends up in the water. After entering the water, it becomes methylmercury and is absorbed by fish. Methylmercury is known to have negative effects on developing minds and nervous systems. The study's lead scientists, who are from the Harvard T.H. Chan School of Public Health, suspect that the ill effects of mercury exposure may be more far-reaching than that. They posit that exposure to mercury in the womb may, "limit the ability of nervous system tissues to grow and develop in response to increased aerobic fitness."

Gwen Collman, Ph.D., and director of the NIEHS Division of Extramural Research and Training, said, "We know that neurodevelopment is a delicate process that is especially sensitive to methylmercury and other environmental toxins, but we are still discovering the lifelong ripple effects of these exposures." She added that this research has highlighted adult cognitive function as an additional concern.

For the study, 197 participants were recruited from the Faroe Islands, which lie 200 miles north of England. There, fish is a dietary staple. The researchers have been following their health since the late 1980s, when all of them were still in the womb. At age 22, the subjects participated in an exam that measured their VO2 max, or the rate at which they can use oxygen, which is an indicator of aerobic fitness. The young adults also took part in tests that measured short-term memory, long-term storage and retrieval, verbal comprehension, psychomotor speed, visual processing and cognitive processing speed.

Unsurprisingly, the researchers found that higher VO2 max scores correlated with better neurocognitive function. This was expected, given the results of prior studies. What was particularly interesting though, was what the researchers discovered when the subjects were divided into groups based on prenatal mercury exposure.

The scientists discovered that these benefits were only seen in the group with a low amount of mercury exposure. Study subjects with prenatal methylmercury levels of less than 35 micrograms per liter in umbilical cord blood demonstrated better cognitive efficiency with higher VO2 max. However, participants who were exposed to higher amounts of methylmercury did not exhibit any cognitive benefits as VO2 max increased.

Collman stated, "We know that aerobic exercise is an important part of a healthy lifestyle, but these findings suggest that early-life exposure to pollutants may reduce the potential benefits. We need to pay special attention to the environment we create for pregnant moms and babies."

Of course, a great way to do that would be to reduce the amount of industrial waste we create – but that probably won't be happening anytime soon.

Sources:

MedicalNewsToday.com

NRDC.org

Science.NaturalNews.com