Copious amounts of research on the damaging health effects of sleep deprivation exist, but not much is discussed regarding the opposite: sleeping too much. Now, a new study finds that both sleep deprivation and too much sleep increases low-grade inflammation, an immune system response that can contribute to obesity, chronic pain, depression, and diabetes — in addition to blood copper levels.

The researchers examined serum micronutrient concentrations, particularly copper, in the blood of people who slept too long (over 10 hours a night). They found that high copper serum concentration was linked to lengthy sleep duration. In the past, out-of-sorts serum micronutrient concentrations have been associated with a decline in physical function and health in older people, as well as other health issues.

Copper levels in the blood can tell us many things about our health. For one, adults have about 50-80 milligrams of copper in their body, located in the muscle and liver. Copper helps the body make melanin, bone, and connective tissue. Lifestyle choices like diet and exercise all influence copper levels, as well as other micronutrient concentrations, in the body. Too much copper is toxic to organs, killing liver cells and harming the nervous system — and it can also create an imbalance in zinc and iron in your body.

High concentrations of serum copper has been linked to cardiovascular disease and pro-oxidative stress; so the researchers had to take this into account. Even still, they discovered that heart disease didn’t necessarily have much to do with it.

“Nevertheless, when the study participants’ cardiovascular diseases were taken account for, our results remained unchanged,” Maria Luojus, an author of the study, said in the press release. “The association between serum copper concentration and sleep duration persisted independently of cardiovascular diseases.”

More research will need to be done to further examine the link between sleeping too much, copper levels, and inflammation. But past research has already proven that sleep in general is extremely important to our health; depriving yourself of the correct amount of sleep (seven to eight hours) can increase inflammation in women with heart disease, break down the immune system, impair your memory, and contribute to anxiety and depression.

Like eating food or even exercising, everyone is different — but there is often a happy medium when it comes to sleep. According to the National Sleep Foundation, teenagers should be getting eight to 10 hours of sleep a night, while adults should be getting seven to nine hours. Older adults over the age of 65 generally need less sleep, from seven to eight hours. Aiming to maintain sleep hygiene and get the full eight hours every night will make a big difference in not only your energy level, but also long-term effects on your body.

Source: Luojus M, Lehto S, Tolmunen T, Elomaa A, Kauhanen J. Serum copper, zinc and high-sensitivity C-reactive protein in short and long sleep duration in ageing men. Journal of Trace Elements in Medicine and Biology. 2015.