How does one’s body knows when it’s time to sleep? There are two main factors that determine when you want to sleep and when you want to be awake. The first factor is a signal beamed out from your aproximately twenty-four-hour clock located deep within your brain. The clock creates a cycling, day-night rhythm that makes you feel tired or alert at regular times of night and day, respectively. The second factor is a chemical substance that builds up in your brain and creates a “sleep pressure.” The longer you’ve been awake, the more that chemical sleep pressure accumulates, and consequentially, the sleepier you feel. It is the balance between the two factors that dictates how alert and attentive you are during the day, when you will feel tired and ready for bed at night, and, in part, how well you will sleep.
Sleep vs health: Routinely sleeping less than six or seven hours a night demolishes your imune system, more than doubling your risk of cancer. Inadequate – even moderate reductions for just one week – disrupts blood sugar levels so profoundly that you would be classified as pre-diabetic. Short sleeping increases the likelyhood of your coronary arteries becoming blocked and brittle, setting you on a path toward cardiovascular disease, stroke, and congestive heart failure. Sleep disruption further contributes to all major psychiatric conditions, including depression, anxiety and suicidality.
Perhaps you have also noticed a desire to eat more when you are tired? This is no coincidence. Too little sleep swells concentrations of a hormone that makes you feel hungry while supressing a companion hormone that otherwise signals food satistaction. Despite being full, you still want to eat more. It’s a proven recipe for weight gain in sleep-deficiency adults and children alike. Worse, should you attempt to diet but don’t get enough sleep while doing so, it is futile, since most of the weight you loose will come from lean body mass, not fat. The less sleep you have had, or the more fragmented your sleep, the more sensitive you are to pain of all kinds. The most common place where people experience significant and sustained pain is often the very last place they can find sound sleep: a hospital.
Your twenty-four-hour tempo helps to determine when you want to be awake and when you want to be asleep. But it controls other rhythmic patterns, too. These include your timed preferences for eating and drinking, your moods and emotions, the amount of urine you produce, your core body temperature, your metabolic rate, and the release of numerous hormones.
Sleep vs caffeine: As sleep pressure mounts, a chemical called adenosine is building up in your brain. The longer you are awake, the more adenosine will accumulate. As a result an irresistible urge for slumber will take hold. It happens to most people after twelve to sixteen hours of being awake. You can however, artificially mute the sleep signal of adenosine by using a chemical that makes you feel more alert and awake: caffeine.
Caffeine is not a food supplement. Rather, caffeine is the most widely used (and abused) on the planet after oil. The consumption of caffeine represents one of the longest and largest unsupervised drug studies ever conducted on the human race, perhaps rivaled only by alcohol, and it continues to this day. Rather, caffeine blocks and effectively inactivates the receptors, acting as a masking agent. It’s the equivalent of sticking your fingers in your ears to shut out a sound. Levels of circulating caffeine peak approximately thirty minutes after oral administration. What is problematic though, is the persistence of caffeine in your system. In pharmacology the term “half-life” is used when discussing a drug’s efficacy. It refers to the length of time it takes for the body to remove 50% of a drug’s concentration. Caffeine has an average half-life of five to seven hours.
Caffeine – which is not only prevalent in coffee, certain teas, and many energy drinks, but also food such as dark chocolate and ice cream, as well as drugs such weight-loss pills and pain relievers. Also be aware that de-caffeinated does not mean non-caffeinated. One cup of decaf usually contains 15 to 30% of the dose of a regular cup of coffee.
Ageing also alters the speed of caffeine clearance; the older we are, the longer it takes our brain and body to remove caffeine, and the more sensitive we become in later life to caffeine’s sleep disrupting influence.