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How interrupted sleep affects our mood and overall health

“Sometimes I wake up Grumpy. Other times I let them sleep in.”

Nocturnal awakenings are very common. But how much do they interfere with our mood and health?

Whether it’s the neighbour’s dog barking at shadows, your youngest crying with earache, you worrying about tomorrow’s presentation, your partner’s snoring, a menopausal flush or a prostatic nocturnal pee, an interrupted night’s sleep will feel worse than getting too little sleep because of the negative impact it has on sleep architecture.

With 60% of the adult Australian population reporting some form of sleep difficulty three or more times a week and nearly 15% dealing with chronic insomnia, prioritising ways to overcome this would appear an imperative to preserve cognitive function as we age.

Below, you’ll discover just a small snippet of the research around how interrupted sleep affects our mood, cognition, memory, and immunity.

How sleep interruptions affect focus and mood

The bidirectional relationship between sleep and mental health is well documented. The advent of smart technologies enabling individual sleep monitoring led to a large UK study which examined sleep quality in 89,205 participants who agreed to wear an accelerometer 24 hours a day for a week. This allowed the researchers to compare ten different metrics of sleep between participants who had previously been diagnosed with a mental illness and those that hadn’t. Their findings support the idea that understanding a person’s quality of sleep is just as important as measuring the quantity when concerned with their mental health.

We know addressing sleep disturbance first in cases of anxiety and depression have been shown to help alleviate symptoms. This strategy can also be helpful for those with PTSD, who may be hindered by sleep disturbances and nightmares. Successfully getting the patient to increase quality sleep has been shown to support positive mood changes and reduce the risk of future relapse.

As far as mood, too little rapid eye movement (REM) sleep means you’re missing out on the fine tuning required for emotional regulation and cognition. That groggy start to your morning means you’re less focussed and more easily distracted. Your reaction time is slowed, putting you at higher risk of having an accident on the way to work, for example. It also means that all those items you carefully attempted to memorise yesterday have disappeared faster than Harry Potter can say “Quidditch.”

A small study conducted by researchers from Johns Hopkins showed frequent forced awakenings over 3 consecutive nights lowered positive mood by 31%. In contrast, those who were deliberately sleep-deprived with no forced awakenings had a 12% reduction in positive mood. Lack of time in deep sleep, due to disruption to the normal sleep cycle, leads to feeling unrefreshed, lack of energy, and poor mood. Those especially at risk of interrupted sleep include healthcare workers, first responders, and new parents. Additionally, regular interrupted sleep over a 6-year period, has been linked to a x1.5 increased risk for developing Alzheimer’s disease.

How sleep interruptions affect cognition

Research tells us there is a “sweet spot” when it comes to how much quality sleep we should be getting. It comes back to the need for homeostasis. Too little sleep (<7 hours) raises amyloid-beta and tau levels, while too much sleep (>9hrs) has been associated with decreased memory and episodic learning.

While Yaffe and others have shown sleep disturbance is a risk factor for cognitive decline and Alzheimer’s Disease in adults, so does sleep loss associated with hypoxia (as in obstructed sleep apnoea (OSA)). Poor sleep and inadequate oxygen supply associated with OSA appears to have a link to an increased risk of autoimmune conditions such as lupus and rheumatoid arthritis, believed to be mediated by cytokines.

In addition, in a random prospective study from the US, it was discovered that middle-aged adults who reported insomnia symptoms, or chronic insomnia, and slept for less than six hours, were twice as likely to have cognitive impairment compared to good sleepers. This association was also found to be stronger in those with co-existing cardiometabolic conditions.

How sleep interruptions affect immunity

Getting sufficient good quality sleep supports a well-functioning immune system, which is why repeated disturbed nights increases your susceptibility to going down with the latest lurgy that’s doing the rounds.

Mouse studies have found that microglia, the immune cells involved in maintaining synaptic health, function and pruning and primarily active during sleep.

Sleep is an active physiological process vital to optimal health. But in our increasingly sleep deprived and sleep interrupted society, we have self-sabotaged our health by creating  a chronic inflammatory state that raises the potential risk not only for neurodegenerative disease such as Alzheimer’s and Parkinson’s Disease, but also infectious, cardiometabolic, autoimmune and neoplastic disease.

In summary

Sleep. It’s essential to life and optimal function. While there is still much to learn, as Lifestyle Medicine practitioners, we can use this information to better understand how to positively impact our patients’ and clients’ lives. As more information is discovered, we continue to learn ourselves the strength of the relationship between our brain, the process of sleep, and good cognitive, emotional, physical, and mental health. Lifestyle Medicine practitioners can support patients by building their knowledge around the importance of quality sleep and how it affects us mentally and physically.


This article has been written for the Australasian Society of Lifestyle Medicine (ASLM) by the documented original author. The views and opinions expressed in this article are solely those of the original author and do not necessarily represent the views and opinions of the ASLM or its Board.

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