Through data analysis, the researchers found that people who took long naps had higher body mass indexes and were more likely to have metabolic syndrome than those who did not take naps.
Lifestyles mediating associations between naps, obesity and metabolic health Summary Aim The objective of this study was to determine the association between naps/no naps and obesity, considering the duration of the nap (long: >30 minutes, short: ≤30 minutes), and to test whether the characteristics of the nap and/or the factors Lifestyle factors mediate the association of napping with obesity and metabolic syndrome (MetS). Methods This was a cross-sectional study of 3,275 adults from a Mediterranean population (the Obesity, Nutrigenetics, TIming, and MEditerranean [ONTIME] study) who had the opportunity to take naps because it is culturally ingrained. Results 35% of the participants used to take naps (16% long naps). Compared with the no-nap group , long naps were associated with higher values of BMI, waist circumference, fasting glucose, systolic blood pressure, and diastolic blood pressure, as well as with a higher prevalence of MetS (41%; p = 0.015). On the other hand, the probability of having high SBP was lower in the short nap group (21%; p = 0.044) than in the no nap group. Smoking a greater number of cigarettes per day mediated the association of long naps with higher BMI (by 12%, percentage of association mediated by smoking; p < 0.05). Similarly, delays in nighttime sleep and feeding schedules and higher energy intake at lunch (the meal preceding the nap) mediated the association between higher BMI and longer naps by 8%, 4 % and 5% (all p < 0.05). Napping in bed (vs. couch/chair) showed a trend to mediate the association between long naps and higher SBP (by 6%; p = 0.055). Conclusions Nap duration is relevant in obesity/MetS. Timing of sleeping and eating during the night, energy intake at lunch, smoking, and nap location mediated this association. |
Importance of the study
What is already known?
The midday nap is a common practice in many countries to recover from the harmful effects of insufficient sleep. However, the relationship between naps and metabolic health is still not well understood.
What does this study add?
This study, in a Mediterranean population, shows that those who napped a lot had a higher BMI and were more likely to have metabolic syndrome than those who did not nap. In contrast, people who took short naps were less likely to have elevated systolic blood pressure.
We identified possible lifestyle mediators in the association between long naps and metabolic alterations. Those mediating factors are nighttime sleep schedule, meal schedule, energy intake at lunch, smoking, and nap location (bed vs. couch).
How might these results change the direction of research or the focus of clinical practice?
Nap duration may be relevant in clinical practice for the treatment of obesity and metabolic syndrome.
The results call for studies to investigate whether short naps are advisable over long naps, especially in individuals with behaviors that mediate the association between long naps and obesity, such as delayed meal and sleep schedules, or in those who smoke. Additionally, studies are needed to evaluate whether lower caloric intake at lunch decreases the deleterious effects of prolonged naps on obesity and systolic blood pressure.
Comments
It is a common custom in some countries for people to take a nap at noon. Sleeping during the middle of the day has the potential to affect sleep quality, cognitive function, and metabolic processes. However, the relationship between naps and metabolic health is not well understood. A new study led by researchers at Brigham and Women’s Hospital, a founding member of the Mass General Brigham health system, evaluated more than 3,000 adults in a Mediterranean population, examining the relationship of naps and nap duration with obesity. and metabolic syndrome.
Researchers found that those who napped 30 minutes or longer (long naps) were more likely to have a higher body mass index, higher blood pressure, and a host of other conditions associated with heart disease and diabetes (metabolic syndrome). compared to those who do not nap. However, for those who had short naps, also known as "power naps," this increased risk of obesity and metabolic disturbances was not present. naps The team’s results are published in Obesity .
“Not all naps are the same. "Length of time, sleep position, and other specific factors can affect the health outcomes of a nap," said lead author Marta Garaulet, PhD, visiting professor in the Division of Circadian and Sleep Disorders at Brigham and Women’s. s Hospital. “A previous study we conducted in a large study population in the United Kingdom found that napping was associated with an increased risk of obesity. “We wanted to determine whether this would be true in a country where naps are more culturally ingrained, in this case Spain, as well as how nap duration relates to metabolic health.”
Obesity is a growing health problem that affects more than one billion people worldwide. The accumulation of fat in the body is related to the way food is digested during metabolic processes. Understanding how lifestyle choices, such as napping, affect these metabolic mechanisms could help researchers learn how habits influence health.
The researchers examined data from 3,275 adults in a Mediterranean population, specifically people from the Spanish region of Murcia. Participants’ baseline metabolic characteristics were measured at the University of Murcia and a napping survey collected additional details about their naps and other lifestyle factors. This resulted in the categories of no naps, less than 30 minutes, and more than 30 minutes.
The research team found that people who took long naps had a higher body mass index and were more likely to have metabolic syndrome (MetS) than those who did not nap. Furthermore, compared with the no-nap group, the long-nap group had higher values of waist circumference, fasting glucose levels, systolic blood pressure (SBP), and diastolic blood pressure. The researchers found that long naps were associated with later sleeping and eating times, with greater energy intake at lunch and cigarette smoking, and with the location of naps (a bed in front of a couch), which may explain the higher risks associated with longer nap durations.
While this is an observational study and it is possible that some factors may be a consequence of obesity and not napping per se, a previous study of data collected in the UK Biobank pointed to a causal relationship between napping and obesity , particularly with abdominal obesity. , the most harmful way. In the current study, the authors found a variety of statistically significant lifestyle factors that mediate the association between napping and health measures. The study results call for future research to investigate whether a short nap is advantageous over a long one, particularly for people with habits such as delaying meal and sleep schedules, or for those who smoke.
“This study shows the importance of considering nap length and raises the question of whether short naps may offer unique benefits. Many institutions are realizing the benefits of short naps, primarily for work productivity, but increasingly also for overall health. If future studies further corroborate the benefits of shorter naps, I think that could be the driving force behind the discovery of optimal nap lengths and a cultural shift in recognizing the long-term effects on health and productivity increases that can result from this lifestyle behavior,” said co-author Frank Scheer, PhD, senior neuroscientist and professor in the Medical Chronobiology Program in the Brigham Division of Sleep and Surgery.
Another study presented at the European Congress of Preventive Cardiology analyzes the link between nap duration and the risk of atrial fibrillation.
Excessive daytime naps linked to atrial fibrillation risk
Daytime naps of 30 minutes or more are associated with a higher likelihood of developing atrial fibrillation, according to research presented at ESC Preventive Cardiology 2023, a scientific conference of the European Society of Cardiology (ESC).
“Our study indicates that daytime naps should be limited to less than 30 minutes,” said study author Dr. Jesús Díaz-Gutiérrez, of the Juan Ramón Jiménez University Hospital, Huelva, Spain. “People with disturbed nighttime sleep should avoid relying on naps to make up for the deficit.”
Atrial fibrillation is the most common heart rhythm disorder, affecting more than 40 million people worldwide. 2 People with this arrhythmia have five times the risk of stroke than their peers. Dr. Díaz-Gutiérrez said: “Previous studies have suggested that sleep patterns may play a role in the development of atrial fibrillation, but to our knowledge, this was the first study to look at the relationship between daytime naps and sleep. risk of arrhythmia.”
The study used data from the University of Navarra (SUN) Monitoring Project, a prospective cohort of Spanish university graduates. A total of 20,348 participants free of atrial fibrillation at baseline completed a questionnaire every two years. Information was obtained on sociodemographic data (age, sex, work schedule), medical conditions (high cholesterol, high blood pressure, diabetes, sleep apnea, cardiovascular diseases, including atrial fibrillation), lifestyle (naps, smoking, exercise , coffee consumption, excessive alcohol consumption, adherence to the Mediterranean diet, watching television), height and weight.
Participants were divided into three groups based on the average daily nap duration at the start of the study: none, less than 30 minutes, and 30 minutes or more. Short-day nappers were defined as those who slept less than 30 minutes.
New diagnoses of atrial fibrillation were initially self-reported and subsequently confirmed by an expert committee of cardiologists, who used a predefined protocol that included review of medical records. The risk of atrial fibrillation was analyzed according to the duration of the daytime nap after adjusting for the information collected in the questionnaire.
The average age of participants at the start of the study was 38 years and 61% were women. During a median follow-up of 13.8 years, 131 participants developed atrial fibrillation. Compared with those who napped for a short day, those who napped for 30 minutes or more a day had almost twice the risk of developing atrial fibrillation (hazard ratio [HR] 1.90; confidence interval [CI] 95 % 1.26–2.86). Meanwhile, compared with short naps, the risk was not elevated in those who avoided napping (HR 1.26, 95% CI 0.82–1.93).
The researchers conducted a second analysis to identify the nap duration associated with the lowest risk of atrial fibrillation. This analysis included those who reported taking regular naps and excluded participants who did not nap. Participants were divided into three categories based on the average daily nap duration at the start of the study: less than 15 minutes, 15 to 30 minutes, and more than 30 minutes.
Compared with those who napped more than 30 minutes a day, those who slept less than 15 minutes had a 42% lower risk of developing atrial fibrillation (HR 0.58; 95% CI 0.35–0.95), while those who napped for 15 to 30 minutes had a 56% reduced risk (HR 0.44, 95% CI 0.27–0.72).
Dr. Díaz-Gutiérrez said: “The results suggest that the optimal nap duration is 15 to 30 minutes. Larger studies are needed to determine whether a short nap is preferable to no sleep at all. There are numerous potential explanations for the associations between napping and health. For example, long daytime naps can disrupt the body’s internal clock (circadian rhythm), leading to shorter nighttime sleep, more nighttime awakenings, and reduced physical activity. "In contrast, short daytime naps can improve circadian rhythm, lower blood pressure levels, and reduce stress."
