It’s not uncommon in this day and age to witness a sort of “fear mongering” approach to medical advice. News headlines about health risks often sound as bombastic as celebrity scandal coverage, with warnings about various ingredients in our food that can give us cancer or other catastrophic health conditions. The issue with interpreting these warnings is that there is often an underlying political agenda, usually against a specific food manufacturer or similar organization. However, some serious health risks and implications are largely ignored by the general public. This is one such case.
Many studies have shown that short sleepers (people who get less than 7 hours of sleep each night) and long sleepers (people who sleep for more than 8 hours per night) face an increased risk of early death. If you look at the mortality rate chart shown in many of these studies, you will notice a repeating U-shaped pattern that spells it all out for you. In this article, we will look into these studies and examine the risk factors that can contribute to this early death statistic. This information will be able to help you plan your sleep schedule and general lifestyle to improve long-term health.
Note: Don’t be scared into thinking that short and long sleeping put you in guaranteed danger. Your medical history and individual physiological quirks, as well as your environment, are much more important factors to consider over whether you should be asleep for 7 or 8 hours. If you’re concerned, speak to your primary care physician.
The Concept of Relative Risk
Relative risk or risk ratio (both are abbreviated as RR, thankfully) is an epidemiological term used to describe probability. Epidemiology is the term for scientific analysis of studies and data, specifically related to the distribution and determinants of diseases and other health conditions in various populations. Epidemiologists try to narrow down specific risky behaviors that increase the chances of disease and other issues. The way the resulting information is presented may look convoluted and unintuitive at first, but it’s quite sensible. Let’s look at an example unrelated to sleeping:
You take two groups of people at a dinner event. One group is composed of vegetarians who avoid the steak portion of the buffet. The other group freely indulges in this steak dish. Thirty people eat steak, and 15 of those experience illness and nausea. Twenty people eat only the vegetable portion of the meal, and only 3 of them get ill. The relative risk ratio for the steak lovers is 0.5, while the vegetarians are facing a relative risk of 0.15. It means that people who ate steak were more than three times more likely to experience nausea compared to vegetarians. It points to the assumption that steak was the main cause of illness at the dinner event, although it cannot be considered irrefutable proof.
Separate potential factors can become “confounding factors,” meaning that they influence both the suspected cause and the outcome, which can muddy the research results and cause inaccuracies. Confounding factors and determinants are isolated and controlled through methods like stratification – sampling various subpopulations within the target population to find only the most relevant common factors.
In the context of sleep disorders or today’s specific topic (early death as a result of long or short sleeping), there is a list of common determinants to work with. If you’ve been reading any articles about sleep disorders, you can probably name a good handful of factors – stress, alcohol consumption, dietary habits, medical history, levels of exercise, etc. In this article, we’re looking at short and long sleeping as a possible factor that contributes to early death.
The association between sleep duration and overall mortality has been shown in over 20 studies to this day. They all present the familiar U-shape pattern centered around the 7h sleep duration mark. While the mortality risk of regular sleepers is 1, short sleepers bump it up to 1.1, and long sleepers have a mortality risk of 1.23. However, it isn’t enough information to base a conclusion on, and the direct causes of those deaths should be examined. Sleep disorders are not considered a cause of death, but the weakened immune system you get can cause dangerous and potentially lethal health problems.
Let’s look at cancer and cardiovascular disease; two very common causes of death in the United States. Short sleepers have a relative risk of 0.99 when it comes to dying of cancer, meaning they’re only a tiny bit less likely to meet that end than normal sleepers. However, their relative risk of dying of cardiovascular disease is 1.06, a noticeable notch above average. Long sleepers have it the worst when it comes to these two conditions – their risk ratio for death by cancer is 1.21, and they have a relative risk of 1.38 for cardiovascular disease-related death.
Studies that deal with this sort of topic often function as a long-term monitoring process with questionnaires that get filled in by the subjects (often pairs of twins for convenience) each year or every couple of years. Because a lot of contributing factors for early death may exist in their lives, extra questions are included about their daily or weekly habits – things such as alcohol consumption, diets, levels of exercise, tobacco smoking, the presence of sleeping medication or any other significant drug that can influence the findings. Most studies tend to focus on cancer and cardiovascular disease.
The Allostatic Load Theory
The idea of the allostatic load has not exactly been widely accepted by the academic and medical circles thus far. However, it could be a key factor in explaining why abnormal sleep leads to increased mortality. The way it works is easy to understand on a basic level – allostasis is the process of achieving homeostasis. Homeostasis is a stable state of internal chemical distribution, and it is necessary for our body to function properly. A simple example is body temperature, where your body stops functioning properly if you go even slightly higher than the regular value.
The allostatic load is essentially the combined “wear and tear” your body experiences as it is exposed to chronic or repeated stress. Your nervous system responds to this stress in an intensified or fluctuating way, which has negative physiological consequences. Individual systems within the body respond to the overall state of the body, and the brain anticipates your needs and regulates the release of hormones and the processing of stimuli in advance to compensate. However, if the issue remains unresolved, the brain will continue pumping an increased amount of hormones, which isn’t healthy. One of these issues is sleep deprivation, and this idea goes a long way towards explaining why short sleepers have an increased mortality risk. Allostatic load is considered a key factor in many diseases and problems that a majority of seniors face. The longer a person is alive, the more wear and tear their body experiences, leading to health issues.
You’ll notice that most of this applies primarily to short sleepers. There is a different potential explanation for the increased mortality risk of long sleepers. The idea is that long sleep is most likely caused by one of a large number of potential underlying conditions. The fatigue that various illnesses cause can increase the amount of time a person spends asleep, and while the long sleep itself won’t be the cause of death, it is a warning sign that something much more dangerous (and likely undiagnosed) is happening under the surface. If the long sleep is diagnosed as hypersomnia, then the other conditions are considered co-morbid – meaning that they coexist with this sleeping disorder.
Changing Your Sleep Patterns
The idea of early death and mortality risks could cause some people reading this to get worried. After all, if someone is health-conscious and avoids harmful foods, then it is only natural that they would try to change their sleep schedule. However, it can be complicated to suddenly move your entire sleeping window to another part of the day, or force yourself to sleep more or less than what you’re used to. That’s why we recommend a series of steps you can take to fix your schedule without disrupting your normal daily routine and performance:
- Before attempting to make any sort of big changes to your lifestyle, keep a sleep journal for a couple of weeks. Sleep tracking is an excellent way to become more aware of how much sleep you’re getting, and get other relevant information. Try to keep this journal for a while even after you make alterations to your sleeping schedule, since the information may be useful later on.
- Consult your doctor about your plan. This step seems like a no-brainer, but so many people try things recklessly and get ill as a consequence. If your journal makes you suspect you have a sleeping disorder that’s causing you to sleep for more or less time than is ideal (which is 7-8 hours in this case), give them the journal, so they know what you’re dealing with. If they suggest a polysomnography session or other similar diagnostic tests, agree to them, since it’s crucial to know how you normally sleep and whether you’re dealing with a condition. Follow their diet advice or exercise recommendations, as these routines will help you live healthy even if they don’t directly affect sleep.
- Use an alarm or similar device to wake up exactly when you need to. Even if you’re unemployed or otherwise free to wake up at any time you want, investing in a smart alarm or a special lamp is a good idea. These alarms and lamps wake you up without instantly shocking you out of deeper sleep, usually through sleep stage detection or by slowly increasing the light in your room to emulate sunrise. Your circadian rhythm is governed by an internal biological clock that responds to light levels around you, so these lamps can help you feel refreshed when you get up.
- Avoid daytime naps. Short sleepers are sometimes tempted to take quick daytime naps to “freshen up,” but this can disrupt their sleep schedule and do more harm than good. It’s good to be very tired before you hit the sack, as it can help you sleep for longer.
Co-founder of Counting Sheep and Sleepaholic