Many people enjoy taking a nap during the day. A short nap can help people feel refreshed, improve alertness, and provide extra energy.
However, new research suggests that long daytime naps may not always be harmless, especially for people living with type 2 diabetes.
Scientists have found that people with type 2 diabetes who nap for more than 30 minutes every day may have a higher risk of developing metabolic dysfunction-associated steatotic liver disease, or MASLD. The findings were presented at ENDO 2026, the annual meeting of the Endocrine Society in Chicago.
MASLD is a common chronic liver condition that occurs when too much fat builds up inside the liver. The disease was previously called nonalcoholic fatty liver disease, or NAFLD.
The name was changed recently to better reflect the fact that the condition is closely linked to problems with metabolism, including obesity, insulin resistance, high blood sugar, and type 2 diabetes.
The liver is one of the body’s most important organs. It helps process nutrients, stores energy, removes harmful substances from the blood, and produces proteins needed for many body functions. When excess fat accumulates in the liver, it can interfere with these processes.
In its early stages, MASLD often causes no symptoms. Many people do not know they have the disease until it is discovered during blood tests or imaging scans. Over time, however, the condition can become more serious.
In some people, liver inflammation develops, leading to scarring and permanent damage. In severe cases, the disease can progress to cirrhosis, liver failure, or liver cancer.
People with type 2 diabetes are already known to have a much higher risk of developing MASLD than the general population. Researchers are therefore interested in finding simple ways to identify which patients may be at the greatest risk.
Sleep habits have attracted attention because sleep affects many processes in the body, including blood sugar control, hormone production, appetite, and metabolism.
The new study was led by Dr. Xuejiang Gu, executive director of the Endocrinology Department at the First Affiliated Hospital of Wenzhou Medical University in China.
The research team collected information from 1,900 adults with type 2 diabetes between the ages of 18 and 85. The participants answered questionnaires about their sleeping habits between 2017 and 2024.
The researchers divided the participants into four groups. The first group had good sleep at night and took short naps during the day. The second group had good sleep at night but took long daytime naps. The third group had poor sleep at night and short naps. The fourth group had both poor sleep at night and long naps during the day.
The participants were followed for a little more than three years on average. During that time, 379 people developed MASLD.
When the researchers analyzed the data, they found a clear pattern. Compared with people who slept well at night and took short naps, all of the other groups had a higher risk of developing MASLD. Even people who slept well at night but took long naps had an increased risk.
The risk became especially high among people who combined poor nighttime sleep with long naps. According to Dr. Gu, this combination more than tripled the risk of developing MASLD.
The findings suggest that daytime napping may not simply make up for poor sleep at night. Instead, long naps may be linked to changes in metabolism that increase the chances of developing fatty liver disease.
The researchers believe the findings are important because sleep habits are daily behaviors that people can change. Unlike age or genetics, sleep patterns can potentially be improved through lifestyle adjustments and better sleep routines.
The study also highlights the importance of looking beyond traditional medical tests when assessing health risks. Simple questions about sleep duration and napping habits may help doctors identify people with type 2 diabetes who need closer monitoring for liver disease.
The study has several strengths. It included a large number of participants and followed them for several years. However, there are also limitations. Sleep habits were based on questionnaires, which depend on participants accurately remembering and reporting their behavior.
In addition, the study cannot prove that long naps directly cause fatty liver disease. It only shows that the two are linked.
Even so, the findings provide another reminder that sleep plays a major role in overall health. For people living with type 2 diabetes, paying attention to both nighttime sleep and daytime napping may be an important step in protecting liver health.
If you care about diabetes, please read studies about 5 vitamins that may prevent complication in diabetes, and how to manage high blood pressure and diabetes with healthy foods.
For more health information, please see recent studies about vitamin D and type2 diabetes, and to people with type 2 diabetes, some fruits are better than others.
Source: Wenzhou Medical University.
