A warning is in order here. I became intensely engrossed in researching this blog. Sleep is fascinating! My two dogs actually got into the trash and demolished some tissues all over the floor — right in front of me — without my noticing because I was reading all these absorbing articles on sleep and sleep deprivation.
This post is a little longer than most because of all the incredible knowledge I was inhaling. But read on through. If you want to know more, both Healthy Sleep and WebMD are wonderful sources of information.
And if you just want to know how it ends, sleep is vital to your health and well-being. Not getting enough rest? See the companion blog on Essential Oils and a Good Night’s Sleep.
* * *
Do you get enough sleep? Do you feel refreshed in the morning? Or do you have to drag yourself out of bed after two or three cycles of the snooze alarm?
I usually but not always get enough sleep. But I never really gave it much thought: sometimes I sleep well; sometimes I don’t. It never occurred to me that that could be much of a problem.
But it is.
The Harvard Women’s Health Watch, as reported in Harvard Health Publications, cites six reasons that underscore the importance of restful sleep for overall health and well-being. Their six reasons are as follows:
1) Learning and memory: Sleep helps the brain commit new information to memory.
2) Metabolism and weight: Chronic sleep deprivation may cause weight gain by affecting the way our bodies process and store carbohydrates, and by altering levels of hormones that affect our appetite.
3) Safety: Sleep deficit contributes to a greater tendency to fall asleep during the daytime, which can lead to accidents.
4) Mood: Sleep loss may result in irritability, impatience, inability to concentrate, and moodiness.
5) Cardiovascular health: Serious sleep disorders have been linked to hypertension, increased stress hormone levels, and irregular heartbeat.
6) Disease: Sleep deprivation alters immune function, including the activity of the body’s killer cells. Keeping up with sleep may help fight cancer.
Let’s delve a little more deeply into these items.
Learning and Memory
Another study from Harvard, this one from Healthy Sleep, goes into more detail on the relationship between sleep and learning/memory. Sleep, learning, and memory are complex phenomena that are not entirely understood, but studies do suggest that the quantity and quality of sleep have a profound impact on learning and memory. It’s theorized that there are two effects in play.
First, a sleep-deprived person cannot concentrate optimally and therefore cannot learn efficiently. Second, sleep itself has a role in the consolidation of memory, which is essential for learning and storing new information.
Consolidation (distinct from acquisition, which is the introduction of new knowledge, and recall, which is the ability to access information) represents the processes by which a memory becomes stable.
Acquisition and recall occur only during wakefulness, but research suggests that memory consolidation takes place during sleep through the strengthening of the neural connections that form our memories. Although there is no consensus about how sleep makes this process possible, many researchers think that specific characteristics of brainwaves during different stages of sleep are associated with the formation of particular types of memory.
Metabolism and Weight
As WebMD explains, there are two aspects to the metabolism and weight management problem. First, behaviorally, lack of adequate rest could prevent us from exercising or from cooking a healthy dinner because we’re just too tired and lacking in energy.
Second, there’s a physiological issue. Leptin is a hormone that plays an important role in making us feel full. Lack of sleep causes leptin levels to drop, thus making us feel hungrier than we do when we have adequate sleep.
To make matters worse, ghrelin, the hormone that tells us to eat, increases with lack of sleep. More ghrelin plus less leptin equals weight gain.
Furthermore, the foods we crave when we’re tired are high-fat, high-calorie offerings in particular. It starts out innocently enough. We’re tired during the day; we need to stay awake; we reach for something from the candy machine to get us through the afternoon. That doesn’t really do the job, so we grab some more comfort food. Anything to give us a little energy. Thus we make unfortunate food choices when we’re tired.
The safety issue is perhaps the least surprising negative aspects of lack of sleep. If we’re tired during the day, we’re more apt to fall asleep, if only for a second, than otherwise. In this age of rapid activity, we can’t afford these lapses.
What if our work involves heavy equipment? What if we nod off while driving? There are so many situations in which it’s dangerous to be overtired.
Note how this circumstance interacts with the weight issue. We reach for high-calorie foods when we’re sleepy but need to stay awake. How often do we snack in the car to keep ourselves going?
WebMD tells us that “drowsiness can slow reaction time as much as driving drunk. The National Highway Traffic Safety Administration estimates that fatigue is a cause in 100,000 auto crashes and 1,550 crash-related deaths a year in the U.S.” These facts are dismaying — all these preventable accidents.
We’re all aware of the relationship between sleep and mood. We’re “grumpy” when we’re tired. But the sleep deprivation problem can be much more serious than simply being out of sorts.
Sleep problems, according to Harvard’s Healthy Sleep may actually contribute to psychological problems. Chronic insomnia, for example, may increase the risk for developing feelings of sadness and of anxiousness.
Lack of sleep may also interfere with our ability to cope with stress. This problem is significant considering the amount of stress in contemporary Western society.
How can sleep affect cardiovascular health, one might ask. Well, although the mechanisms are not understood, poor sleep has been linked to high blood pressure, atherosclerosis, heart failure, and heart attack.
As reported by the Society for Cardiovascular Angiography and Interventions (http://www.scai.org/SecondsCount/Treatment/HealthyLiving/SleepandCardiovascularDisease.aspx ), “Poor sleep appears to increase substances in your body, such as c-reactive protein, that indicate inflammation is a problem. So, inflammation, which is how the body responds to injury, infection or disease, may be part of the reason poor sleep affects your cardiovascular system. Poor sleep also causes the body to produce more stress hormones, which may contribute to cardiovascular disease.”
In addition, as WebMD (http://www.webmd.com/sleep-disorders/features/how-sleep-affects-your-heart) notes, our heart rate and blood pressure decrease while we’re asleep. This phenomenon decreases the work of the heart, thus giving it a “rest” from its hard-working routine.
Lack of sleep interferes with the working of the body’s immune system in fairly complex and not-fully-understood ways. Cytokines, a type of protein, are the principle messengers of the immune system. During sleep, your immune system releases cytokines (some of which in turn help promote sleep).
According to the Mayo Clinic, “Certain cytokines need to increase when you have an infection or inflammation, or when you’re under stress. Sleep deprivation may decrease production of these protective cytokines. In addition, infection-fighting antibodies and cells are reduced during periods when you don’t get enough sleep.”
* * *
Need more rest? Check out my blog on the topic of getting to sleep. And let me know your own experiences. I’d love to hear from you!