Unexpected impact of plastics in everyday items on sleep revealed

Plastics found in everyday items can disrupt sleep as much as caffeine, a new study has found. The study is the first to show that chemicals in plastics throw off the body's internal clock by 17 minutes.

Chemicals found in common plastics may disrupt the body's natural 24-hour sleep-wake cycle and circadian rhythm like coffee, increasing the risk of sleep disorders, diabetes, immune problems and cancer, new research suggests.

The study, The Guardian reports, looked at chemicals released from a PVC medical feeding tube and a polyurethane hydration pack used by long-distance runners. PVC and polyurethanes are also used in everything from children's toys to food packaging and furniture. The findings show for the first time how chemicals from plastics are likely to disrupt cellular signals that regulate the body's internal clock, throwing it off by 17 minutes.

The internal clock is “incredibly important for physiology and overall health,” although more research is needed to determine the exact effects of exposure, said Martin Wagner, co-author of the study and a plastics chemistry researcher at the Norwegian Institute of Science and Technology.

“This study adds to a growing body of evidence that plastics contain compounds that cause a wide range of toxic effects,” the authors wrote in a peer-reviewed study published in Environmental International. “A fundamental shift in the design and production of plastics is needed to ensure their safety.”

The circadian rhythm is the molecular clock that regulates activity and fatigue depending on the time of day and night, explains The Guardian. Altered rhythms have been linked to increased risk of obesity, dementia and cardiovascular disease, among other things.

Research into the toxicity of plastic chemicals has most often focused on how chemicals like phthalates and bisphenol A interfere with the endocrine system, with hormone-related effects that can last for years. The new paper looked at another biological pathway: on cells. It tested for adverse effects on the adenosine receptor, a key component of cellular control of the internal clock and involved in signaling that regulates circadian rhythm.

The biological process by which the chemicals in plastic act on the body is similar to the way caffeine acts on the circadian rhythm and the adenosine receptor. Caffeine deactivates the adenosine receptor, thereby increasing the circadian rhythm and keeping us awake. The chemicals in plastic activate the adenosine receptor, but also have a similar effect of keeping us awake.

This receptor is located in the brain and “sends signals to the body that say, ‘The sun is coming up – let’s start the day,’” says Martin Wagner. But when chemicals activate the adenosine receptor, it may not transmit the signal, delaying the body’s natural physiological processes.

While the chemicals aren't as potent as caffeine, their effects on cellular processes happen much faster than plastics' effects on hormones, Wagner says.

What that means for the body is unclear, but it's probably not good, Wagner notes.

“We don’t know how significant it is, and you could say, ‘Oh, it’s only 15 minutes, so it’s no big deal,’ but it’s such a tightly controlled clock that it’s a significant shift,” he added.

The study was done in vitro, meaning on human cells in the lab, and Wagner said the next step is to study how the chemicals affect zebrafish, which have some physiological processes going on in their brains that are similar to humans.

Future research will also look at which chemicals in plastic and PVC affect the sleep-wake cycle. PVC can contain any of 8,000 chemicals, some of which are not intentionally added but are by-products of the manufacturing process, making it an incredibly complex material to work with.

The results of each new study will be used to pressure lawmakers to pass regulations and to try to persuade industry to remove chemicals from plastics, Wagner said.