You may wish to understand a bit more about the science of sleep. In this blog, we’ll share a ‘sleep 101’ with you and over the next few weeks, continue to share more tips on pre sleep routines, natural sleep supplements, regulating your sleep with jet lag and more!
Why sleep is important
I encourage you to place priority on sleep quantity and quality. Sleep is critical for cognitive function, focus and self-control. When it is deficient or imbalanced, this is one of the top causes for inflammation, slow recovery, depression and poor sugar control which can lead to food cravings.
Sleep is the time during which the body is able to access a primary anabolic state where there is an increase in growth hormone and testosterone – 2 crucial muscle repairing hormones that have been shown in one study to affect your neural growth and the way you feel during a day. Your body needs sleep to repair from physical exercise– a lack of sleep can impact your body taking it 2 – 3 times longer to recover from exercise than if you had received good sleep. During sleep, the body also restores the adrenal glands and enters a process of detoxification by the liver which rebuilds the immune system protecting the body from opportunistic bacteria resulting in infection. Cumulative lack of sleep puts your body into a catabolic state of continuous hormonal depletion which speeds up the aging process.
Understanding the 101 of sleep
The basics of sleep science lie in our circadian rhythms which we touched on briefly in our nutritional science series. It is important to understand this 24 hour cycle in more detail as it is the clock against which all our cycles operate.
From 6am cortisol is activated and surges through our system to awaken our brain and body. At the same time, the hormone vasoactive intestinal polypeptide (knowing as VIP) is released and causes great wake up actions including:
- Increased contractility of the heart
- Vasodilation (blood vessels widening)
- Liver glycogenolysis (breakdown of liver’s glycogen to naturally raise your blood sugar)
- An increase in the hormone ghrelin (hunger hormone) to ensure you fuel up to provide your body with energy to start the day
VIP also has the unique function of relaxing the muscles in the trachea to improve oxygen inhalation for activity and it also relaxes the muscles of the stomach and gall bladder which in systems that are optimal, often explains how within 2 hours of waking, many people will have a thorough bowel movement.
Our friend the sun
Our circadian rhythms are kickstarted and normalised with decent exposure to morning sunlight. Sunlight maximises cortisol release in the morning which sets in place the routine for it to decline naturally later in the day. This is vital for sleep preparation. If you can’t get a minimum of 5 (up to 20 minutes is ideal) of sunlight exposure in the morning, you can maximise the release of cortisol with moderate amounts of coffee and green tea but nothing is quite as effective as natural sunlight.
At about 09h00/10h00 our body’s sex hormone secretion peaks. This is helpful information for those who struggle with low libido. At about 14h30, muscle coordination and reaction time peaks so this is a great time to engage in sports requiring sharp hand eye coordination and muscle responsiveness. At around 17h00, cardiovascular efficiency, body temperature, muscle repair and protein synthesis peak so this is an even better time of the day to exercise if your workout for the day is intense. Easier aerobic exercise can take place in the morning and harder weight or interval training should be done later in the day. It is however important to be sure that you allow at least 4 hours between completion of a workout and bedtime.
At sunset the body’s blood pressure peaks along with your body temperature. As we discuss in our blog on biohacking your deep sleep, this is why an evening shower or cold soak can help you sleep better as it lowers your core temperature. It is during sunset that leptin is released from the fat stores. When your circadian rhythm is optimal leptin is able to do its job and can shift your body into fatty-acid utilisation, suppress appetite, and control any late-night food cravings. Leptin release can be inhibited however if we expose our bodies to too much artificial light or consume large dinners so it is important to be mindful of this if you’re wanting to normalise your circadian rhythm.
If you need to use your devices or work on your computer after sunset, be sure to protect your eyes with BLUblocking glasses (Made To Thrive recommends BLUblox and clients of Made To Thrive receive 15% discount on purchases) or install Iris Software on our devices (Made To Thrive clients receive a 10% discount on Iris software purchases).
We want to limit artificial light exposure so that our bodies can start to produce the hormone melatonin which signals to the brain it is time to slow activity and start to recuperate. At around 22h00, a protein called agouti peaks. This can stimulate appetite in the same way that ghrelin does unless leptin is there to counter this. This explains late night snacking or the cravings we may have after a meal, for something sweet. It is important to close the door on agouti as this precipitates a vicious cycle of poor sleep, bad behaviour of snacking (which impacts blood glucose and high insulin levels) which can result in fat gain. In addition, gastrointestinal activity starts to decline at around 23h00 and so additional caloric intake is not digested optimally.
Melatonin is at its peak at about midnight. This is when leptin enters the hypothalamus area of the brain. This is critical for metabolism, weight control and fat loss because the letpin signals the release of fat reserves which tells the thyroid to upregulate its function. This is why obesity is often linked to lack of sleep.
Melotinin also plays a role in slowing down the neurons in the brain allowing the nervous system to heal and memory and learning to be cemented. This is the reason we feel alert and responsive after a good night’s rest. When melatonin peaks, the hormone prolactin is also released. A deficiency in proalactin (often found in postmenopausal women) can cause a decline in brain activity, a propensity to gain weight, and result in high levels of inflammatory cytokine molecules associated with lack of recovery and chronic pain. On the flipside, balanced prolactin levels increase the recycling of cells, the renewal of cells, and the creation of new cells. It also promotes the release of growth hormone.
My colleague Ben Greenfield notes that if not much prolactin is released while you sleep, you tend to produce less growth hormone, which can cause low levels of DHEA, another very important hormone. Low levels of these hormones result in reduced cardiac function and reduced skeletal muscle function. You can now understand that, if there is not sufficient melatonin or leptin doesn’t enter the hypothalamus, there will be some serious repercussions, especially for heart health, muscle repair, full-body recovery, and daily physical performance.
Between 02h00 and 06h00, the body’s core temperate falls to its lowest levels. It is during this time that optimal nervous system repair, neuron growth, up-regulation of immune system response and decrease in inflammation, takes place. But, in order for the core temperature to drop to its lowest, you need to have been asleep for 6 hours– another important reason to ensure that you are in bed early. This is the most natural way to control body temperature but as discussed in our blog on Biohack Your Deep Sleep, you can use a device such as the Chilipad to support this drop in body temperature.
The drop in body temperature signals to the body to begin producing cortisol which starts the entire cycle again from about 06h00. We then rise and so commences the important circadian cycle.