Having poor sleep may seem like an issue that impacts you only the next day. Unfortunately, there is a lot of research connecting insufficient sleep with health issues, mainly cardiovascular disease.
“Only 65% of adults in the U.S. regularly sleep the recommended 7 hours per night, and there’s a lot of evidence suggesting that this lack of sleep is associated with cardiovascular disease in the long term,” said Anne-Marie Chang, co-author of the study.
Sleeping 5 hours during the week and 10 on the weekend
The researchers recruited 15 healthy men (20-35 years old) to participate in their sleep study. The study lasted for 10 nights and was set up to simulate a work week with short sleep followed by a weekend with longer sleep. Here is how they did it:
- For 3 nights, the participants were allowed to sleep up to 10 hours per night to get to their baseline sleep level.
- For 5 nights, the participants were restricted to 5 hours of sleep per night.
- For 2 nights, the participants were again allowed to sleep up to 10 hours per night.
The researchers measured the resting heart rates and blood pressure of participants every 2 hours during the day to evaluate the effects of this sleep regime on cardiovascular health. They intentionally measured so many times during the day because both heart rate and blood pressure fluctuate during the day. So, the multiple measurements allowed them to account for these natural daily changes.
Heart rate and blood pressure increased with each bad sleep
The study found that heart rate increased by nearly 1 beat per minute (BPM) with each day of the study. The average heart rate at the beginning of the study was 69 BPM, while the average heart rate at the end of the study was nearly 78 BPM.
It’s a similar story when it comes to blood pressure. Systolic blood pressure increased by about 0,5 mmHg per day. The average blood pressure in the beginning was 116 mmHg and it reached nearly 119,5 mmHg by the end of the study.
For both blood pressure and heart rate, this increase was measured after those two days of long sleep. So, this study speaks clearly, catching up on the weekend doesn’t undo the negative effects of poor sleep during the week.
“Both heart rate and systolic blood pressure increased with each successive day and did not return to baseline levels by the end of the recovery period. So, despite having the additional opportunity to rest, by the end of the weekend of the study, their cardiovascular systems still had not recovered,” said lead author David Reichenberger.
Make sleep a priority throughout the whole week
The researchers noted that if you miss multiple nights of good sleep, you are likely to need much longer than a weekend to fully recover. They also urge people to focus on improving sleep.
“Sleep is a biological process but it’s also a behavioural one and one that we often have a lot of control over. Not only does sleep affect our cardiovascular health but it also affects our weight, our mental health, our ability to focus and our ability to maintain healthy relationships with others, among many other things. As we learn more and more about the importance of sleep, and how it impacts everything in our lives, my hope is that it will become more of a focus for improving one’s health.”