Alarm Clocks and Heart Attacks: Tell Me Why I Don't Like Mondays
Voldemort, the Joker, the Decepticons. We've had some decent villains in our time. But no villain is as persistent and reviled as the one that sits right next to our beds: the alarm clock. Oh, that wicked little instrument of cruel and unusual torture. There is no escaping it. No matter how hard or how often we slam that snooze button, the dreaded sound is back again the following morning. And then the morning after that. And the one after that.
Photo by Alan Cleaver.
And this is precisely why Gear4's Renew SleepClock looks so interesting. The $200 clock monitors your breathing and movements and uses these data to measure your sleep patterns -- allowing you to access them on their iPhone app. You don't set up a time to wake up, but rather a window of time, and -- using both the compiled data and your breathing to determine whether you're in light or deep sleep -- the clock decides when it will be the least jarring to rouse you, which it will do by putting on the radio or playing something from your music library.
Curious about whether this would work, I hit up Bora Zivkovic, the editor of Scientific American blogs and a chronobiologist (which is someone who studies biological rhythms, such as sleeping).
"Do not know the details, but if an alarm clock can monitor your sleep cycle and wake you up during a safer phase, there would be fewer heart attacks -- as well as more pleasant mornings," Zivkovic told me over e-mail.
Heart attacks? Zivkovic referred me to a post he'd written in 2008. In it he describes human rhythms during the course of the day: cardiovascular activity peaks in the afternoon and slows at night while we sleep. He writes:
Around dawn, heart rate and blood pressure gradually rise. This is a direct result of the circadian clock driving the gradual rise in plasma epinephrine and cortisol. All four of those parameters (HR [heart rate], BP [blood pressure], Epinephrine and Cortisol) rise roughly simultaneously at dawn and reach a mini-peak in the morning, at the time when we spontaneously wake up.
This rise prepares the body for awakening. After waking up, the heart parameters level off somewhat and then very slowly rise throughout the day until reaching their peak in the late afternoon.
When we allow ourselves to rise spontaneously, we tend to do so at the time our cardiovascular parameters have reached the morning-time peak that enables optimal awakening. Unfortunately, few of us wake up spontaneously, using instead the dreaded alarm clock, that jarring device that jolts us awake long before our cardiovascular parameters are ready to release us into the day.
Of course, as Zivkovic points out, one could technically "entrain to the daily Zeitgeber -- the ring of the alarm-clock -- with a particular phase-relationship." Meaning, if we stuck to a pattern of going to bed at a certain time and waking at a certain time, we could train our bodies to be better prepared to wake.
The problem arises when we let our schedules fall out of sync on the weekends when we don't have to get up as early. As a result, come Monday, our sleep cycle is not quite far enough along when the buzz of the alarm jolts us awake, causing our stress hormones to jump and leading to an immediate spike in blood pressure and heart rate.
For the healthy adult, this is something we can recover from easily enough -- we do so every morning, after all, crankiness notwithstanding. But for anyone with heart trouble, this could spell disaster, says Zivkovic, pointing out that over 30 percent of heart attacks occur on Mondays between six and noon and that the most dangerous Monday of all is the one that first occurs after we set our clocks forward one hour in the spring.
The researchers of a 2008 study that confirmed these points noted:
It has been postulated that people in Western societies are chronically sleep deprived, since the average sleep duration decreased from 9.0 to 7.5 hours during the 20th century. Therefore, it is important to examine whether we can achieve beneficial effects with prolonged sleep. The finding that the possibility of additional sleep seems to be protective on the first workday after the autumn shift is intriguing.
Monday is the day of the week associated with the highest risk of acute myocardial infarction [heart attack], with the mental stress of starting a new workweek and the increase in activity suggested as an explanation. Our results raise the possibility that there is another, sleep-related component in the excess incidence of acute myocardial infarction on Monday. Sleep-diary studies suggest that bedtimes and wake-up times are usually later on weekend days than on weekdays; the earlier wake-up times on the first workday of the week and the consequent minor sleep deprivation can be hypothesized to have an adverse cardiovascular effect in some people.
This effect would be less pronounced with the transition out of daylight saving time, since it allows for additional sleep. Studies are warranted to examine the possibility that a more stable weekly pattern of waking up in the morning and going to sleep at night or a somewhat later wake-up time on Monday might prevent some acute myocardial infarctions.
If this new clock could find a way to gently rouse people when they are closer to the optimal place in their morning cardiovascular cycle, then it could be hugely beneficial. Lacking the clock for an informal trial (it has not yet been released), we'll have to hold off on an anecdotal verdict. But let this post serve as a warning to try and get more regular sleep.
And make sure you check out Zivkovic's article to learn the differences between acute and chronic sleep deprivation and what kids of hell subjecting your body to the latter can unleash on your life.