Understanding Sleep
Sleep is a necessary part of health, longevity, and all around survival. I find that, in general, people understand that sleep is important. But this ‘understanding’ frequently is not put into practice (meaning, people are frequently short-changing their sleep) and I believe that may be due to the fact that the complexities of sleep (it IS complex) have not been well communicated.
In my medical clinic, I have seen individuals apply important and pertinent life changes in their metabolic health when they finally understand what is going on with their health, why their body is acting a certain way, and why the recommendations will help. With this knowledge, changes for improvement become prioritized and with that, improvement is inevitably achieved. Woot!
So my intention with the information below is to provide a brief summary of sleep and hope to pique interest and reconsideration as to why it is important not to sacrifice sleep. I’ll scratch the surface on the different stages, the purpose of each stage, how short changing it affects health, and lifestyle habits to improve sleep! If you want to understand more about how it links specifically to hormone health, make sure to check out my December 2023 blog detailing this!
Sleep Stages
Sleep is categorized as Rapid Eye Movement (REM) and Non-Rapid Eye Movement (NREM) sleep.
A sleep cycle consists of NREM and REM sleep. The amount of time NREM and REM take up in each sleep cycle, however, differs throughout the night. In general, a sleep cycle lasts about 90 minutes and there are several sleep cycles throughout one night of sleep.
In the early part of the night when one is asleep, the sleep cycle is mostly dominated by NREM sleep. During this type of sleep brain waves are slow and the brain is working hard to consolidate memories of the day and removing information from storage that is no longer necessary. In NREM sleep there are four further sub-stages: Stage 1, Stage 2, Stage 3, and Stage 4 sleep. The higher the number (stage 3 and 4), the deeper the sleep. It takes much more effort to awaken an individual from stage 3 and 4 sleep, compared to the earlier stages.
As sleep progresses later into the evening, REM sleep becomes more predominant. Brain waves during REM sleep actually look strikingly similar to brain waves of someone who is awake. During this type of sleep is where dreaming occurs and connections are made between past events, creativity flourishes, or even problem solving occurs!
Both REM and NREM sleep hold significant importance. By falling asleep too late, we sacrifice the opportunity for sufficient NREM sleep and if we awaken too early, we then sacrifice the opportunity for sufficient REM sleep. A consistent pattern of doing this will result in long-term effects on cognition, mental clarity, energy level, and health.
Ideal Length of Sleep
Several research studies have indicated that the ideal amount of sleep is between 7 to 9 hours each night. Occasionally sleeping more than 9 hours a night to make up for sleep debt (aka short sleep) accrued within the several days before is fine and normal. However, if someone routinely is sleeping greater than 9 hours a night, that could actually signal a medical problem and should be investigated further.
How someone gets in their 7-9 hours, depends on the individual. Some people prefer to go to bed early and wake up early and are referred to as ‘early birds’ (that’s me!). Whereas, other individuals prefer to stay up late and wake up later and are known as ‘night owls’. One is not better than the other. However, sometimes work schedules can infringe upon the natural circadian rhythm of people and so, for example, night owls who have to wake up early to get to work may have significantly more difficulty with tasks throughout the work day due to this sleep infringement. The opposite is true for early birds, who, if working shifts, may need to stay up late for a shift and may also experience the same difficulty with tasks later in the evening. Flexible start times with certain companies have become more available to address these differences in individual’s circadian rhythm tendencies with overall benefit to company productivity.
Metabolic Consequences of Sleep Deprivation
Why is it such a big deal to get enough sleep?
Many important hormones are made while we sleep and important cellular repair processes are underway during sleep. If we limit the time for these things to happen, over time, health is negatively impacted. For example, insulin resistance increases, leading to higher blood sugars and an increased risk of type 2 diabetes. Blood vessel stiffness rises, leading to higher blood pressure, a risk factor for heart disease. Hunger hormones increase and satiety hormones decrease, which leads to increased caloric intake and putting an individual at risk for obesity. Lower testosterone, abnormal menstrual cycles, and impacted libido are also potential consequences of poor sleep quality and quantity.
Healthy Sleep Habits
Many experts will state that the most important habit to establish in order to improve sleep is to set a sleep time- and STICK to it!
Here are some additional habits to consider:
Set a sleep time and go to bed at this time daily. Avoid making it a moving target at all costs.
Hydrate well throughout the day. Dehydration will result in elevated core temperature when sleeping and this will decrease sleep quality.
Avoid caffeine at least 9 hours prior to your sleep time. Caffeine competes with adenosine, the molecule that is instrumental in making one feel tired and assisting the body in entering a sleep state. If adenosine cannot adequately bind to the receptors, then sleep onset does not happen.
Avoid bright lights, especially blue lit screens (phones, computers, TVs, laptops, bright digital clocks, tablets, etc) at least one hour prior to bed. Bright light, especially the blue wavelength lights prevalent in our digital devices, are potent suppressors of melatonin, the hormone produced by the pineal gland and is the ‘go’ buzzer that signals to the brain, it is time to initiate sleep. If there is no buzzer being signaled by melatonin, then sleep initiation is delayed.
Journal thoughts down in the evening, for example, after dinner. Instead of storing emotions, to-do lists, questions, and trying to organize and continuously cram them into our brain space and memory stores with pressures to recall them the following day, writing them down in the evening can release that pressure and prevent middle-of-the night awakenings with racing thoughts.
Other quick habits or habit adjustments that can be helpful:
Taking a warm shower or bath in the evening - helps cool core body temperature!
Drinking hot herbal tea in the evening - helps cool core body temperature!
Prioritize exercise earlier in the day and not close to bedtime - some individuals can be especially sensitive to the adrenaline release of exercise that can interfere with sleep onset.
White noise - this can drown out ambient noise that may lead to middle of the night awakenings
Sleep mask - the gentle pressure and the complete blackout it provides ensures no interference with melatonin secretion and may also assist with a person staying asleep, once asleep
Sleep quality and quantity is a question I ask of all my patients, since something as ‘basic’ as not getting enough sleep can be the reason response to therapy is not as robust as expected. Notice that in the list above, sleep aids are not listed, and this intentional. Sleep aids are actually not helpful in assisting a person get quality sleep. While it can make someone sleepy, the frequently cause grogginess in the morning or lead to a dependency of use. The more we can prioritize and protect sleep, the more these habits will become second nature and help us lead healthier lives.
Want to read more about sleep? I highly recommend:
“Why We Sleep” by Matthew Walker, PhD