Is napping linked to high blood pressure?

Napping is a very common routine for some people, especially when they have finished their workday and need a break after lunch. However, a study published in the journal Hypertension has revealed a possible danger of this typical custom. As is often the case, the nuances of the study are an important factor to understanding the risk.

Can napping really increase risk of stroke?

According to this research published by the aforementioned journal associated with the American Heart Association, ‘the aim of this study was to investigate the association between daytime napping frequency and the incidence of essential hypertension or stroke as well as to validate causality in this relationship via Mendelian randomization (MR)’. It found that taking naps regularly is related to high blood pressure and an increased risk of cardiovascular incidents.

For the study, data was provided by 360,000 participants about their napping habits to UK Biobank, which is a large biomedical database and research resource in the United Kingdom, and analyzed.

Research results revealed that those who napped regularly were 12% more likely to develop high blood pressure over time, and 24% more likely to have a stroke than people who had never taken a nap. The clinical psychologist at Banner University Medical Center in Tucson, Arizona, Michael Grandner, explained the reason for this relationship.

“Although napping itself is not harmful, many people who nap may do so due to lack of sleep at night, which is associated with poorer health, and naps do not compensate.“ For her part, the director of the Northwestern Sleep and Circadian Medicine Center, Phyllis Zee, explained in statements collected by ‘CNN’ how this relationship occurs.

"The results show that napping increases the incidence of hypertension and stroke, after adjusting for many variables known to be associated with the risk of these diseases." In addition, for this study the participants had to submit blood, urine and saliva samples on a regular basis to the UK Biobank.

The results of this study contrast with those offered by other scientific research carried out recently, which endorse napping as a very healthy practice for people. According to the study ‘Biological Rhythms and Behavior,’ the nap is a natural consequence of the descent of blood from the nervous system to the digestive system that occurs after eating, that is, most of the body’s blood goes to the stomach to carry out healthy digestion.

Origin of the nap

According to the ‘BBC’, the origin of the siesta dates back to the Roman Empire. The word ‘siesta’ comes from the Latin ‘sexta’, which refers to the sixth hour of the day. The Romans divided the day into 12-hour light periods.

In the case of Spain, where the siesta is so famous, the sixth hour of the day corresponds to the time between 1 in the afternoon in winter and 3 in the afternoon in summer. It began there after the Spanish Civil War, a period when it was common for a worker to have more than one job to support his family and would come back at noon to eat and rest, and in this way be able to perform sufficiently at work in the afternoon, as explained by the CIESE University Center.