Can I still sleep in the afternoon?

*For medical professional reading reference only

Sleep is very important to human health.

Essential hypertension is a leading cause of premature death, and stroke is a non-negligible cause of disability

Nap is really the happiest thing after a hard working morning (except for fishing), but the unresolved relationship between naps and high blood pressure and stroke makes lazy naps "dangerous"

Professor Wang E and his team screened the data of over 500,000 subjects in UKB according to the inclusion and exclusion criteria, and finally included a total of 358,451 subjects, including 50,507 patients with essential hypertension, with an average of 11.

Research Process

The researchers asked the subjects whether they had a nap habit through a questionnaire and asked the subjects to choose among standardized outcomes (never or rarely, sometimes, often, and unwilling to answer)

However, nap habits and frequency may change over time.

nap frequency stability

So is napping just a personal habit? Is there any difference between people with different napping habits, does this affect the relationship between napping and disease?

Analysis of the basic data of 358,451 subjects found that subjects who were elderly, male, with low levels of education and income had a higher average nap frequency during the week.
Conditions such as hypercholesterolemia or type 2 diabetes
.

At the same time, these subjects slept for a long time every day, and the quality of sleep at night was poor due to insomnia, snoring and sleeping late
.

Is the increased cardiovascular risk associated with frequent naps associated with insufficient or poor quality sleep at night? A 2019 European Heart Association study found [1] that naps increase the risk of cardiovascular events in people who sleep more than 6 hours a night, but not in people who sleep less than 6 hours at night
.

Based on this, they speculate that napping is a compensatory mechanism for people who do not get enough sleep at night, so it does not increase the risk of cardiovascular events
.

In this study, Wang E et al.
adjusted for factors such as age, gender, race, BMI, waist circumference, smoking and drinking history, education level, sleep duration, and whether or not to snore.
The risk of essential hypertension was increased by 7%, and the risk of stroke and ischemic stroke was increased by 12% and 9%, respectively.
12%, 24% and 20%
.

Excluding subjects with hypertension, night shifts, and sleep disturbances in the two years prior to follow-up, sensitivity analysis was performed using an adjusted model, and increased napping frequency was still significantly associated with an increased risk of hypertension
.

The above correlation and sensitivity analysis indicated that with the increase of nap frequency, the risk of essential hypertension, stroke and ischemic stroke was significantly increased (if you don't sleep, don't sleep, if you don't sleep tomorrow)
.

The relationship between nap frequency and essential hypertension, stroke and ischemic stroke

The correlation between nap frequency and the above diseases was further analyzed by Mendelian randomization (MR), and single-sample MR was performed using UKB data.
The risk of essential hypertension increased by as much as 40% (P<0.
001), while the correlation between nap frequency and ischemic stroke was not statistically significant (P=0.
60)
.

This result is inconsistent with the observational analysis above, possibly due to the low power of the one-sample MR test
.

Single-sample MR guarantees the homogeneity of research subjects, but cannot solve the problem of false positive rate
.

In order to increase the sample size and reduce the false-positive rate, two-sample MR (the FinnGEN database data was used for the outcome of essential hypertension, and the MEGASTROKE data for the outcome of stroke) was used.
and ischemic stroke (P=0.
023): each level of nap frequency increased the risk of essential hypertension by 43% (P=0.
018) and the risk of ischemic stroke by 29% (P=0.
023).

.

Mendelian randomization to analyze the relationship between nap frequency and hypertension, stroke and ischemic stroke

The results of this study are really "horrifying", is it really impossible to take a nap in the future? Are naps really the 'behind the scenes' for high blood pressure and stroke?

It is still unclear what role naps play in the process of hypertension and stroke, but the increase in inflammatory factors and peak blood pressure after naps may be involved and interfere with them
.

However, in order to clarify the intricate relationship between napping and hypertension and stroke, and to clarify the specific mechanism behind it, it is necessary to study the basic mechanism of napping and other sleep habits related to cardiovascular disease in the future
.

Friends who have purchased the course,

Go directly to the applet to listen to the snack~

references:

1.
Wang, C, Bangdiwala, SI, Rangarajan, S, et al.
Association of estimated sleep duration and naps with mortality and cardiovascular events: a study of 116 632 people from 21 countries.
EUR HEART J.
2019; 40 (20) : 1620-1629.
doi: 10.
1093/eurheartj/ehy695

2.
Yang, MJ, Zhang, Z, Wang, YJ, et al.
Association of Nap Frequency With Hypertension or Ischemic Stroke Supported by Prospective Cohort Data and Mendelian Randomization in Predominantly Middle-Aged European Subjects.
HYPERTENSION.
2022; 101161HYPERTENSIONAHA12219120.
doi: 10.
1161/HYPERTENSIONAHA.
122.
19120

3.
Zhao, H, Gui, W, Huang, H, et al.
Association of long-term sleep habits and hypertension: a cross-sectional study in Chinese adults.
J HUM HYPERTENS.
2019; 34 (5): 378-387 .
doi: 10.
1038/s41371-019-0225-8

4.
Fu, J, Zhang, X, Moore, JB, et al.
Midday Nap Duration and Hypertension among Middle-Aged and Older Chinese Adults: A Nationwide Retrospective Cohort Study.
Int J Environ Res Public Health.
2021; 18 Int J Environ Res Public Health.
doi: 10.
3390/ijerph18073680

Editor in chargeYing Yuyan