Researchers say people who take naps longer than 30 minutes during the day appear to be at higher risk for obesity and high blood pressure.
They note that people who take shorter naps are less likely to have high blood pressure. Experts say longer naps may be a factor in these conditions because they can disrupt nighttime eating habits as well as sleep patterns. Midday naps longer than 30 minutes may be linked to higher body mass index, higher blood pressure, and conditions associated with heart disease and diabetes, researchers say.
In contrast, people who take what many call “quick naps,” meaning sleeping 30 minutes or less in the middle of the day, were less likely to have high blood pressure.
In a new study published in the journal Obesity, researchers at Brigham and Women’s Hospital in Boston assessed more than 3,000 adults from a Mediterranean population, where midday naps are common. The researchers examined the relationship between naps and their duration, on the one hand, and obesity and metabolic syndrome, on the other.
Researchers found that people who took naps of 30 minutes or more were more likely to have higher body mass index, higher blood pressure and other conditions associated with heart disease and diabetes than people who didn’t take a nap. Also, people who took short naps were less likely to have high systolic blood pressure than those who didn’t take naps. Sleep duration, position, and other specific factors can affect the health effects of a nap.
Naps and obesity
An earlier study in the UK already showed that naps were associated with an increased risk of obesity. The next step was to study naps in a country where midday naps are an integral part of the culture. In this case, it was Spain, and studying the link between nap duration and metabolic health.
The research team points out that obesity is a growing health problem that affects more than a billion people worldwide. Fat accumulation in the body is related to how people digest food during metabolic processes. According to the researchers, studying how lifestyle choices, such as naps, affect these metabolic mechanisms could help researchers understand how habits influence health.
Napping Study Results
The team looked at data from 3,275 adults from the Spanish region of Murcia. They measured baseline metabolic characteristics of participants at the University of Murcia and gathered information about their naps and other lifestyle factors. They divided the subjects into categories: no nap, nap under 30 minutes, and nap over 30 minutes. Subjects who took longer naps had a higher body mass index and were more likely to suffer from metabolic syndrome than those who did not take naps. Compared to the group that did not take a nap, the group that took a long nap had higher values for waist circumference, fasting blood glucose, systolic blood pressure (SBP), and diastolic blood pressure.
Longer naps were associated with later nighttime sleep and eating, higher energy intake at lunch, and smoking.
Obesity and sleep
This article provides knowledge about sleep and health risks in a cultural context where napping is encouraged in healthy people, throughout life, while considering other potentially related factors, such as nap length and eating habits. It’s possible that longer naps are a consequence of health issues, not the other way around.
This is a cross-sectional study, which therefore does not make it possible to determine the meaning of these relationships. It is possible that people with obesity sleep less well at night and therefore need to take naps more.
Previous studies have shown that weight loss interventions improve sleep quality. It might be of interest to examine whether sleep interventions, including managing the length of naps (and) improving nighttime sleep, improve weight.
More research on napping is needed
The authors of the study acknowledge that it is possible that certain factors are a consequence of obesity and not of naps as such, given that a previous study of data collected in the UK Biobank showed a causal relationship between naps and obesity, particularly abdominal obesity, which the authors call the most detrimental form.
The authors said they found a variety of statistically significant lifestyle factors that influence the association between naps and health measures. They call for future research to determine whether a short nap is more beneficial than a long nap, especially for people with habits such as delayed meals and sleep schedules, or for those who smoke.
This study shows the importance of considering nap duration and raises the question of whether short naps may offer unique benefits. Many institutions are realizing the benefits of short naps, primarily for productivity at work, but also increasingly for overall health.