• Sleep is a key component of good mental and physical health

  • Neurobiologist Delia McCabe, author of Feed Your Brain, shares her tips for a good night's sleep

  • If you suffer from insomnia, we have specialists to support you here

Anyone who has had a sleepless night knows firsthand how hard it is to get through the next day feeling positive and happy. Researchers have found that experimental subjects limited to four-and-a-half hours sleep per night for one week reported negative mood states such as anger, sadness and feeling more stressed and mentally exhausted. Resuming normal hours of sleep resulted in them feeling dramatically better emotionally. 

Unfortunately, experiencing anxiety and depression can also influence sleep negatively, although researchers do believe that chronic sleep disturbances are often the cause of depression, with studies showing that 15–20% of people diagnosed with insomnia develop depression.

Studies using sleep-challenged rats have found that sleep loss over a period of weeks changes the serotonin neurotransmitter system in the animals’ brains. Serotonin is a critically important neurotransmitter that influences mood, emotion, sleep and appetite. So when its functioning is hampered, it leads to further sleep problems, making for a nasty vicious cycle. In addition, the hypothalamic-pituitary axis (HPA), which is a group of central nervous system (CNS) structures that regulate the stress response, is also altered by chronic sleep loss. 

Adding insult to injury, sleep loss also reduces the volume of the hippocampus, which is the brain's major learning and memory centre, also regulating emotion. And to top off the bad news, activity in the amygdala, which is involved with negative emotions like anger and frustration, increases when sleep loss occurs, leading to increases in these negative emotions along with the inability to regulate them optimally. Our CNS is very similar to that of rats so these deficits are very likely to be mirrored in humans. 

Another research study showed that sleep-deprived human subjects didn’t feel as happy after an achievement as those who were adequately rested. So you end up not enjoying the achievements you’ve been working towards when you are sleep-deprived, and you may be sleep-deprived because you’ve been working towards those achievements! These studies easily explain why it’s so much harder to stay positive and see things in perspective when you are sleep-deprived – your brain is battling to produce happy emotions.

Researchers are not yet precisely sure why sleep is so important, and have argued for decades about the role of sleep. However, new research offers a compelling insight: our brains ‘detoxify’ at night by flushing cerebrospinal fluid (CSF) through our neurons which conveniently ‘shrink’ in size while we are asleep. Accumulated toxins produced through energy production in the brain may be responsible for the negative mood states of sleep-deprived people. A growing group of researchers also believe that Alzheimer’s Disease is linked to chronic sleep deprivation.

Here are a few things to keep in mind while pursuing restorative sleep:

  • Warm milk before bedtime may be comforting but there is no research to support the myth that it promotes sleep. Although milk contains tryptophan (the amino acid that helps to make melatonin, a sleep hormone), it's a large amino acid and therefore loses the competition to get across the blood brain barrier (BBB) to induce sleep against smaller amino acids in milk. However, the psychological aspects of drinking milk, like memories of doing so when a child, can help with stimulating sleepy thoughts and feelings.
  • Herbal teas, such as camomile, may be soothing but are very mild in sleep-inducing action and could increase your nightly visits to the bathroom.
  • Eating well during the day to keep blood glucose levels stable also impacts sleep positively at night, as big blood glucose surges during the day can negatively impact sleep.
  • Do not eat too late as the digestive process can interfere with deep restorative sleep.
  • A high carbohydrate bedtime snack can be useful if you eat dinner very early. Focus on something small like a banana or an apple.
  • Sleep-enhancing herbs like passionflower, valerian root and hops have been shown to be effective but ensure you use a standardised form. A good naturopath would be able to make up a small mixture of these herbs for you to use to assess whether they are helpful.
  • Coffee has a half-life of between five and six hours, which means that the body will take between five and six hours to eliminate half of the caffeine that you consume. So a good rule is to stop drinking coffee at about 2 p.m. if you plan to sleep restfully from 10 p.m.
  • Calcium and magnesium are soothing minerals and can help you achieve a good night's sleep. Focus on calcium and magnesium-rich foods at dinnertime, or supplement with up to 400 mg of calcium and 300 mg of magnesium about an hour before bedtime. If you are very anxious, try 500 mg of magnesium.
  • Essential fatty acids (EFAs) are critical for the structure and functioning of all cell membranes especially in our fatty brains. They are also believed to be intricately involved in our sleep patterns, with animal studies indicating that the pineal gland contains a high percentage of docosahexaenoic acid (DHA) which is a long chain omega-3 EFA. Ensuring that you are getting optimum amounts of these special fatty acids may help you to get back into a good sleeping pattern.
  • Alcohol may put you to sleep, but your sleep pattern will be affected, and generally results in early morning wakefulness.
  • Yoga has been shown to be very useful for its ability to help people who are having sleep challenges.
  • Spend time outside among green trees and nature as much as possible when you have free time. Research has shown that this habit leads to a calmer state of mind and a better stress response.
  • Get outside in the early morning to stimulate your pineal gland to start functioning correctly as indoor unnatural and artificial light can hamper this gland's effectiveness in regulating our sleep/wake cycle. And as we get older our production of melatonin declines, which makes it even more important to get outside at the beginning of the day to keep that pineal gland stimulated, and in so doing, set up the process for going to sleep soundly at night.
  • Avoid stressful experiences as much as possible. For example, avoid reading or watching the news at night.
  • Your body enjoys a proper sleep routine, so go to sleep and get up at the same time every day to establish this sleep pattern. Ensure that your bedroom is uncluttered and peaceful. It should be a haven, not a stress-den.
  • Keep a notebook on your bedside table to record the thoughts that run around your head during the night. It is easier to keep your mind calm and relaxed when you know that you have jotted down your plans for the next day on paper.
  • Stop using all forms of technology (including your smartphone) at least two hours before bedtime as the light from these devices interferes with melatonin production.
  • Some people benefit from taking a supplement called 5-HTP (5–Hydroxytryptophan) about an hour before bedtime. 5-HTP is converted into serotonin and then into melatonin. If this doesn’t help after a few days a doctor can prescribe slow-release melatonin which may be helpful.
  • If general anxiety and stress are causing your sleeplessness, you may try a supplement called GABA (Gamma Amino Butyric Acid), which is a calming neurotransmitter. Supplement between 500 mg twice a day to relax you naturally. In some countries you can only buy the precursor to GABA, called taurine, which then gets converted into GABA. This should be taken in 500 mg doses twice daily after meals, but may need to be taken for a couple of days to result in deep sleep. [Note: 5-HTP and GABA should not be used at the same time as other pharmaceutical medications and should always be used under the direction of your medical practitioner.] 

Your brain evolved to spend a third of its life asleep and short-changing yourself to keep up with family and work commitments or social media will over time lead to feelings of negativity, irritation, frustration, anxiety and ultimately even depression. Deep restorative sleep is an integral part of a mood-management strategy and a great way to stay positive and happy in our busy and complex world. Make sleep a priority!

Delia McCabe is a neurobiologist and the author of Feed Your Brain

Further reading

How CBT can help you overcome insomnia

Can hypnotherapy improve your sleep?

Why do we need sleep in the first place?

10 simple ways to beat insomnia