Better sleep = better life. 

Sleep deprivation, both acute (one night) and chronic (long-term), causes many bad outcomes that are strongly tied to obesity and poor muscle development.

Sleep deprivation encourages adverse weight gain, and is bad for body composition - your ratio of muscle to body fat.  A lack of sleep increases your risk of gaining up to 5kg by 35%, and increases your risk of obesity by 27% (compared to people with optimal sleep patterns).

Sleep deprivation can derail your body composition efforts in four different ways.

#1 - It messes with your hormones

Multiple studies have shown that people who sleep five hours or less per night have higher levels of ghrelin (the hormone that stimulates hunger), and lower levels of leptin (the hormone that suppresses appetite) compared with people who sleep eight hours a night.

#2 - It messes with your DNA

Sleep loss causes molecular changes deep inside our tissues, which predispose a person to negative body composition outcomes of increased fat storage and decreased muscle mass.

Sleep loss can have “double-whammy” effect on cell metabolism and the regulation of gene expression.

Sleep researchers see specific molecular signatures following sleep loss, indicating that fat tissue is attempting to increase its capacity to store fat. Meanwhile muscle tissue goes in the other direction – researchers see a breakdown of skeletal muscle proteins (known as catabolism).

#3 - It messes with your brain chemistry

Some of the mind-altering effects that I discussed in part one of this series can lead directly to body-altering outcomes.

Brain imaging studies have revealed up-regulated neural pathways for food rewards in the brain’s reward-processing areas, following sleep loss. Ghrelin (the appetite stimulating hormone) is also increased in sleep-deprived groups compared to the control groups who got sufficient sleep.

In simulated exercises of food and economic exchange, the sleep-deprived group was willing to spend more money on food items in the decision-making task. The subjects’ brain activity was recorded while they performed these task, and the researchers saw an upregulation of certain signals in the amygdala and hypothalamus which are specific to food rewards.

This shows that sleep deprivation increases our perception of food value, deep in the wiring of our brains.  And this was obvious after just one single night of sleep deprivation.

#4 - It messes with your gut microbiome

There is a strong link between sleep and your gut health, and it seems to be a two-way street:

The health and diversity of the bacteria living in your gut can affect the quality of your sleep, while your sleep and circadian rhythms appear to affect the microbiota in your gut.

Sleep loss has been shown to alter gut microbiota in ways that predispose you to obesity.

Sleep deprivation causes:

• A marked decrease in beneficial types of bacteria
• Changes to the composition of certain micro-organisms in the microbiome that are specifically linked to obesity and type 2 diabetes
• A significant decrease (read: worsening) in insulin sensitivity
  

On top of all that, if you try to diet to overcome these effects, you’ll derail your own efforts unless you’re getting enough sleep. Those changes in gene expression that I mentioned earlier will work against you, ensuring that up to 70% of any weight you lose comes from lean body mass (e.g. muscle), rather than body fat.  And that's definitely not what you're looking for.

Wait, there's more?

Sleep loss has even more tricks up its sleeve, contributing to these adverse effects:

• It worsens athletic performance
• It increases insulin resistance, glucose tolerance, and risk of Type 2 Diabetes
• Your immune function is compromised
• It causes inflammation
• It encourages osteoporosis
• It causes stomach ulcers
• It causes poor skin quality
  

Wrapping up

It's easy to see just how important sleep is for our physical well-being, as well as our mental performance. Lack of sleep can affect us in so many ways, and yet the vast majority of us simply aren't getting enough sleep.

Sleep is a skill just like any other. And just like any skill it can be learnt, practiced, and mastered.

Your virtual sleep coach,

Todd

Sleep deprivation has been linked to some of history’s most high-profile accidents:

• The grounding of the Exxon Valdez oil tanker. 11 million gallons of crude oil were spilled into Alaska’s once-pristine Prince William Sound, causing enormous ecological and economic damage.
• The accident at Three Mile Island, which remains the most significant accident in the history of the U.S commercial nuclear power plant industry.
• The Chernobyl nuclear power plant meltdown, which is considered the worst nuclear disaster in history.
• The explosion of the Space Shuttle Challenger due to a failed O-ring seal in one of its solid rocket boosters. That accident claimed the lives of seven astronauts, and set the US space program back several years.
  

Fatigue and inattention caused by sleep loss has been the cause of many workplace errors, reduced productivity, and serious accidents over many years – including in hospitals and onboard commercial aircraft.

Science has recognised the relationship between sleep and mental performance since the 1930’s. Concentration, reasoning, memory, and mathematical ability are all compromised by sleep deprivation.

So how does sleep affect your mind? Let’s take a look.

Learning and memory

Sleep, learning, and memory are all tightly intertwined. One hundred years’ worth of scientific study in both animals and humans has clearly demonstrated a strong link between the quantity and quality of our sleep, and our ability to learn and remember.

Sleep affects our ability to memorise and learn both before and after a new learning opportunity. 

After insufficient sleep, a sleep-deprived person has more difficulty focusing their attention, which prevents efficient learning and memorisation.

The quality and quality of sleep gained after a learning session has an even greater effect. Sleep has an important role in memory consolidation, which is a major component of learning. Studies have demonstrated that getting a good night’s sleep immediately after learning and memorising a list of verbal facts, resulted in a 20-40% improvement in recall the next day compared to those who had not slept afterwards.

Clear thinking and decision-making

Along with learning and memory, sleep is important for clarity of thought and decision-making.

Studies have shown that as little as one night of sleep loss can impair innovative thinking and flexible decision-making. The harm caused by lack of sleep is particular evident in tasks that require the updating of previous plans to take account of new information.

Studies show that sleep deprivation negatively impacts our ability to make sound decisions in a (contrived) gambling context. Lack of sleep causes people to both over-estimate their expectation of gains, and downplay their losses following risky decisions.

In a simulated exercise of food and economic exchange, a sleep-deprived group was willing to spend more money on food items in the decision-making task than well-rested people were. Scientists recorded their subjects in a functional MRI while they performed the task, noting an upregulation of certain signals in the amygdala and hypothalamus that are specific to food rewards.

This deficit caused by lack of sleep will have a strong effect on body composition, which is covered in more detail in part 2 of this series.

Creativity

People often report feeling more creative in the morning after a good night’s sleep. This is supported by many studies which demonstrate that sleep promotes creative problem-solving, flexible reasoning, and insights.

Researchers think the reason for this is REM sleep, which is typically the last and longest sleep stage that a person experiences just before waking.

Acetylcholine is a brain chemical which surges during sleep, causing the neocortex and hippocampus to interact and form new connections. This can explain why we sometimes wake up in the morning having solved a problem we’ve been thinking about, or gained some new insight into something that’s been ticking away in the back of our minds. This process may be assisted by a relationship between REM and non-REM sleep, working together to create new links between existing knowledge and new solutions.

Reaction time

'Reaction time' is the amount of time taken to respond to an external stimulus. A typical person’s reaction time is somewhere between 160 and 190 milliseconds, which is less than two tenths of a second.

Reaction times increase significantly as a person accumulates sleep debt. Even low levels of fatigue can impair reaction times to the point where they become just as bad as somebody who is legally drunk.

A single night of missed sleep (an “all-nighter”) can triple your reaction time, and the recovery from this via adequate sleep can take several days.

Neurological problems

Lack of sleep can affect your mental health. Sleep is implicated in many and various mental and psychological conditions such as depression and anxiety, seasonal affective disorder, bipolar disorder, ADHD, Alzheimer's and other dementias, schizophrenia, autism, PTSD, and even suicide.

Insomnia and other sleep disorders have long been thought of as merely symptoms of psychiatric disorders. But studies now suggest that the link is bi-directional: sleep problems are a significant risk factor for - if not a direct cause of – psychiatric problems.

During deep sleep, neurons switch off and on in synchronised waves. This in turn causes blood and cerebrospinal fluid to flow back and forth like a tide, in time with these slow waves. The outflow of cerebrospinal fluid carries away toxins such as tau and beta amyloid, which naturally accumulates in the brain and can lead to Alzheimer’s and other diseases if left unchecked.

Wrapping up

It's easy to see just how important sleep is for our mental well-being. Lack of sleep can affect us in so many ways, and yet the vast majority of us simply aren't getting enough sleep.

Sleep is a skill just like any other. And just like any skill it can be learnt, practiced, and mastered.

Your virtual sleep coach,

Todd

Sources: National Sleep Foundation @ https://www.sleepfoundation.org/, and https://pubmed.ncbi.nlm.nih.gov/29073412/

Assuming you're a healthy individual in the 18-to-64 age range with no evidence of a sleep disorder, you should ensure that you're allowing yourself at least eight hours per night.

Start there as your initial goal or starting point, then after a couple of weeks ask yourself these questions:

• Have you been trying to get the full eight hours, but failing?
• Do you need more sleep to get going and feel productive, healthy and happy?
• Do you have health issues such as being overweight? Are you at risk for any disease?
• Are you experiencing any sleep problems?
• Do you need caffeine to get you through the day? 
• Do you ever feel sleepy when driving?
  
• Is your line of work or daily activity level particulalry energy-intensive?
  
• If you're unconstrained by work or your alarm clock, do you sleep for significantly longer than usual?
  

If you answer ‘yes’ to any of these, consider aiming for more sleep.

Track and adjust

Your own perfect sleep amount will be determined by many factors, including your overall health and activity levels. The best way to land on your optimal amount is to track and adjust as necessary.

Most of the damage that under-sleeping can wreak on your mind, body, and spirit becomes evident at around six hours per night or less. So begin by aiming for eight hours, but it’s probably OK if you work your way back towards seven hours.

However you should also be open to moving the other direction, out to nine hours or even more per night, if that’s what your body is telling you it needs.