Previous studies have also found a relation between reduced sleep and low-grade inflammation. Low-grade inflammation is also more common among people who are overweight, depressed and have diabetes. A new study has suggested that middle-aged men who sleep less than six hours or more than 10 hours suffer from low-grade inflammation more often than men sleeping seven-eight hours per night.
This is the first study to analyze the association between sleep duration and serum micronutrient concentrations. It found a link between high serum copper concentration and longer sleep duration. Serum micronutrient concentrations are affected by several factors, including an individual's general health and diet.
Maria Luojus, one of the study researchers from University of Eastern Finland, said, "Based on this study, however, it is impossible to say whether sleeping long results in high serum copper concentrations or vice versa."
High serum copper concentration has been associated with pro-oxidative stress. Pro-oxidative stress is commonly found in many chronic diseases, such as coronary artery disease.
Luojus said, "Nevertheless, when the participants' cardiovascular diseases were taken account for, our results remained unchanged. The association between serum copper concentration and sleep duration persisted independently of cardiovascular diseases."