Chill out: disturbed sleep plays havoc with your mood and mind

A poll by Lifeline released earlier this week shows almost two-thirds of Australians reported sleep loss because of stress relating to work or their finances. The findings went largely unremarked, even though a chronic lack of sleep has serious public health implications.

Sleep theory tells us that there are two key things that determine when we feel like going to sleep. One is simply how long we have been awake, and the other (as any shift worker knows) is the timing of our body clock (this clock controls all our natural rhythms, making us both alert and sleepy across a 24-hour period).

But we also know stress is another major factor affecting our ability to fall and stay asleep. Stress is a popular, loosely-defined word that may be used to cover the full spectrum from daily worries to clinically significant levels of anxiety and depression.

The perils of stress

When daily stressors intensify to the point of increasing central nervous system arousal and preventing good quality sleep, they can set off a downward spiral to poor mental health.

It starts with increased worries and emotional arousal, leading to distorted thinking, such as catastrophising (turning small mistakes into big failures, or believing that everything will go wrong).

You then start to have problems getting to sleep or wake up throughout the night, or both (sleep fragmentation). During the time you're awake, you think endlessly about your life and feel that your thoughts didn't stop when you did sleep.

This lack of good sleep leads to waking up feeling unrefreshed and feeling tired and sleepy the next day. Irritability, changeable emotions, a low mood and poor concentration and attention follow.

And this pattern, repeated over time, increases your risk of depression and anxiety.

As well as negative emotional consequences, other outcomes of chronic poor sleep are deteriorating workplace and community safety (including from dangerous driving) and reduced educational achievement.

A recent review of possible relationships between sleep, depression and anxiety concluded that there was strong evidence that ongoing sleep disturbances may lead to poor mental health.

And many studies now suggest that insomnia is a strong predictor of subsequent clinical depression. This relationship has been documented across multiple age groups, from adolescents to older adults.

Depression and anxiety

While there are several theories about how insomnia may be associated with depression and anxiety, recent evidence shows sleep loss undermines emotional regulation on the following day, altering neural processes that can increase a person's susceptibility to mental illness.

This idea is built on research showing that some emotional processing is dependent on sleep. We also now know that many of the neurotransmitters and brain structures affecting the sleep/wake cycle are also involved in anxiety and depression.

The next step for this line of research is to demonstrate that successful treatment of sleeping difficulties can actually prevent the onset of depression and anxiety.

But the key message for people who are not getting adequate sleep because of stress is that, for most people, improving sleep is not an impossible task.

Typically, it requires a few key changes in your behaviours before bed, getting to sleep and when awake during the night; more relaxation, such as a daily walk outside; and changing unhelpful patterns of thinking and worrying.

Sleep improvements from changes like these are much better sustained in the long term than a short-term fix with sleeping tablets.

Self-fulfilling insomniacs

Identifying the exact sources of your stress and anxiety is also important. While the Lifeline poll found people are losing sleep because of stress related to work and money, many sleep clinicians work with people suffering from insomnia whose key source of anxiety centres around their inability to get a good night's sleep.

They may associate their bedroom with the frustration of waking several times during the night and then being unable to fall asleep again, perhaps due to concerns about not being a good sleeper.

My sleep research team has just completed a study showing that about 85% of the community believe, quite unrealistically, that healthy sleep is unbroken by awakenings across the night.

That's not actually how sleep works; since scientists first began recording sleep in the first half of the 20th century, we have understood that it's a roller-coaster of deeper and lighter sleep. And that it is perfectly normal to have multiple short periods of waking up during the night.

If you are relaxed about your ability to sleep, you may not even realise you have awoken.

Changing community perceptions to understand that healthy sleep doesn't mean perfect sleep every night may help overcome such sources of stress.

One key to ensuring other stressors, such as those identified in the Lifeline poll, don't affect sleep is to create another, different worry time (earlier in the day or evening), well before bedtime. During that time, you should aim to worry constructively, such as by writing out your options.

Later, when you get into bed, take some relaxing breaths, forget about money and work and turn your thoughts to more pleasant things. Don't try too hard to sleep. Just relax and it will come.

Visit the Sleep Health Foundation website for more tips on improving your sleep.