BMJ: How to get a better sleep if you work night shifts

From Optimising sleep for night shifts by Helen McKenna and Matt Wilkes 3rd March 2018

Night shift work happens when your body would rather be asleep. Alertness, cognitive function, psychomotor co-ordination and mood all reach their lowest point between 3am and 5am.

After a night shift is over, the worker has to try to sleep when the body would prefer to be awake. This shift away from the circadian phase compounds the fatigue and can lead to chronic  sleep disturbance. There is  more likelihood of occupational accidents, obesity, type 2 diabetes, heart disease and breast, prostate and colorectal cancers. Psychological and physical well being is affected and accidents or near misses when travelling home are much more likely to occur.

Performance on the night shift gets worse as people get older and it takes longer to recover from a night on.

On average most people sleep about 8 hours a night.  Some people cope with sleep deprivation better than others. Performance will be impaired after two hours of sleep deprivation and gets worse as sleep debt accumulates. Therefore before starting a set of night shifts it is wise to sleep in the morning before, avoid caffeine that day,  and if you can take a nap in the afternoon between 2pm and 6pm.  For a nap to be most effective you need 60-90 minutes asleep.

When you start the shift, try to fit in a nap of about 30 minutes if this is the sort of job that allows this, but have a coffee immediately before the nap, and don’t have any more caffeine after the nap.  Sleeping longer than 30 minutes can make you feel groggy as you move into deep sleep and are the roused from it. Caffeine can help performance but you also want to try to sleep the next morning. Avoid it for the 3-6 hours before you plan to go to sleep in the morning. If you are doing critical tasks especially between 3-5am it is wise to build in more checks to your work.

Working in bright light can perk you up on the night shift.

When it comes to eating you are probably best to eat your main meal immediately before the night shift then eat just enough to feel comfortable as the shift goes on.

Jet lag improves at the rate of one day for every hour you are out of phase.  Circadian adaptation is therefore impossible during short term rotating shift work. Therefore you have to do your best to optimise your sleep between the shifts so as to keep the sleep debt minimal.

If you can possibly arrange lifts home or travelling home on public transport after a night shift, do so.

You can try to improve the situation by wearing sunglasses in daylight on the way home, avoiding electronic device screens, using blackout blinds, ear plugs and eye masks or even white noise generators.  A warm bath and then sleeping in a not cold but cool room and wearing woollen nightwear may help. Melatonin taken in the morning after a night shift has been shown to improve sleep duration by up to 24 minutes. Avoid alcohol and caffeine as these won’t help. Drugs such as Zopiclone can improve sleep if taken during the day but it can be addictive and needs a prescription.

After a run of night shift work you may get into the swing of your regular routine by having a 90 or 180 minute sleep, as this is one or two sleep cycles,  or sleeping in to noon and then getting up and getting outside for some exercise in bright light. Do your best to include meals at the usual times and socialise a little.  You will also need to pay attention to paying back your sleep debt by going to bed earlier than usual and sleeping in later than usual for a few days. It is best to avoid day time naps during the recovery from shift phase.

The path to sleep optimisation is an individual thing. Feel free to experiment.

Retirees are happier when they are active

An Australian study has shown that getting a good sleep at night and being active during the day was the most effective way to boost mood in retirees.

105 people took part in the Life After Work study. They were followed for six month before retirement to 12 months afterwards. They carefully logged their activities and their mood was measured.

The time spent on chores, physical activity, quiet time, screen time, self care, sleep, transport and work, all changed over this period of time. The most favourable substitution was replacing work time with physical activity and sleep.  Replacing work with screen time and social activity showed less effect on mood enhancement.

After retirement, depression, anxiety and stress all reduced.

Olds T et al One day you will wake up and won’t have to go to work: The impact of changes in time use on mental health following retirement. PLoS ONE.2018;13(6);e0199605.doi:101371/journal.pone.0199605. PMID:29953472

Thinking clearly: What is mindfulness all about?

Do you ever just wish you could get someone who knows virtually everything that’s known about the brain and quiz them about mindfulness? Well, I do – a lot – and I just got my wish!

It is my pleasure to present this interview with John McBurney MD. A practicing physician with of over 35 years’ experience, he is board certified in Neurology, Clinical Neurophysiology and Sleep Medicine. Dr. McBurney maintains a daily mindfulness meditation practice as well as home yoga practice.

Could you describe the neurological response to mindfulness practice?

Mindfulness practice ultimately comes down to the concept of neuroplasticity.

In mindfulness, in cultivating awareness of the breath and voluntary moment by moment awareness of the brain, we are training the brain – just like when you are learning to play the violin or any other complex skill – we are training to break out of those self-referential ruminative recursive mental states and to achieve an orientation toward the outer world and in the present moment rather than anticipating the future or reliving the past.

contemplative neuroscience mechanisms behind mindfulness

 Could we be losing something by focusing more on the external realities rather than the self?

Occasionally, we do hear of adverse experiences arising from mindfulness. With any robust intervention there are always potential risks.

How long does it take for mindfulness to have a noticeable effect?

The results can happen almost immediately, however, they are also cumulative. We are still figuring out what the minimum effective dose is. 

What is the relevance of the changes in functional connectivity in the brain in someone who has devoted  a monumental amount of time to meditation, such as Tibetan monks, who may put in more than 10,000 hours in to their practice, compared to the likes of you and me?

A very neat study was published by David Cresswell in Biological Psychiatry in 2016. They invited individuals with high level of stress, unemployed adults, to a weekend retreat experience. They were randomised to in 2 groups:

  • a 3 day mindfulness retreat (the treatment group) and
  • a 3 day relaxation retreat where they read stories, told jokes and had a good time (the control group).

The study was conducted in one centre over one weekend, so it is well controlled. Initially, both groups rated the interventions as being equally helpful to them, subjectively.

The researchers looked at the functional connectivity between the dorsolateral prefrontal cortex and the cingulate gyrus. They also looked at Interleukin-6, a known marker of inflammation, that has been previously shown to be elevated in stressed out unemployed people.

Even with this brief weekend mindfulness intervention, the treatment group developed increased connectivity between the dorsolateral prefrontal cortex and the cyngulate gyrus. There was a neuroplastic response even after a 3 day mindfulness retreat. This was also associated with a decrease in the marker IL-6. Even after 4 months, IL-6 was decreased in the treatment group, but in the control group, IL-6 levels continued to rise, independent of whether they managed to get a job or not.

This is also relevant to doctors, who are at high risk for burnout. Because of their work commitments, the mindfulness retreat for doctors was condensed from the standard 8 week model developed by John Kabat-Zinn to a weekend intervention. The question was: does the weekend model work? The research at the University of Wisconsin where this was developed was reassuring: the residents are less stressed out, more effective and have a greater level of satisfaction.

We still don’t know the absolute minimum dose, but it seems that a weekend of mindfulness can be life-changing for the brain.

Another paper published in PLOS ONE from the Benson-Henry Institute for Mind Body Medicine in Harvard looked at the practices such as meditation, prayer, mindful yoga, Tai-Chi, Qi Gong, etc, i.e. ones that elicit a relaxation response (as opposed the stress response).

This study showed that in both novice and experienced practitioners of relaxation response modalities, there were changes in the epigenetic transcription of the genome. There was upregulation of pathways associated with mitochondrial integrity, downregulation of inflammatory pathways, improved insulin-related metabolism and improved nitric oxide signalling.

Long term potentiation, the standard mechanism for memory formation, strengthens existing neural connections. This happens immediately, as you read this. Over time, long term potentiation leads to formation of new connections,through synaptogenesis, dendritic arborisation and neurogenesis i.e. brain structure changes. In turn, this affects the most neuroplastic neurons located in the hippocampus.

mindfulness minimum effective dose response neurology

In reference to this fascinating recent study of the fight or flight response, it seems plausible that breathing regulates our stress levels much more than conscious thought. Could you explain the significance of this in terms of mindfulness?

The ancients believed that emotions reside in the body. This comes up a lot in serious yoga classes.

This highly innovative study shows that the control of the adrenal medulla – the main effector of the stress response – is not from the conscious ruminating thinking centres, but by the motor and sensory cortex.

This explains why breathing, as well as yoga and Tai-Chi, are an important part of meditative practice. In my experience, these kind of interventions do affect the stress response in a beneficial way.

Mindful exercise exists in many form. For example, weightlifters need to be very mindful to maintain perfect form. Cycling is another example: it is vital to concentrate on every pedal stroke and maintain an even cadence. Once you start to day dream, you notice straight away that your output is way worse. This overlaps with the concept of flow. It is about getting in the zone. There is a very inspiring TED talk by Judson Brewer MD, Ph.D. that explains the physiology behind flow and how it is augmented by mindfulness. Mindfulness is work, and it does require discipline. There is a paradox here of non-striving and non-doing while also being disciplined.

You are a sleep medicine expert. Could you comment on the relationship between mindfulness and sleep?

Insomnia is a complex problem with many causes. However, for most people with idiopathic insomnia, the cause is these self-referential recursive ruminations. They aren’t able to “turn their brain off”. Through mindfulness practice, they are generally able to tame the default mode network that’s responsible for ruminating and daydreaming. A simple strategy would be to lie in bed and concentrate on the breath. This would ease the transition between wakefulness and sleep.

mindfulness default mode network neurological basis for the self

Mindfulness is a mainstay treatment for many mental health disorders. What about use of mindfulness in the treatment for organic pathology of the brain usually treated by neurologists?

There is some preliminary data that mindfulness training has a beneficial effect of seizure frequency in patients with epilepsy. It is a medical condition associated with tremendous anxiety and stress, so mindfulness could have a significant benefit in more than one way. It may even have a benefit it terms of remembering to take medication on time, etc.

Some robust studies show that the frequency of relapse in multiple sclerosis decreases with mindfulness intervention. The effect from mindfulness is similar in magnitude to the effect from beta-interferon. 

John Kabat-Zinn used to take the patients who suffered from chronic pain or had diseases for which we had no answer, and those patients got better. Even beyond neurology, there is some evidence that mindfulness can have benefits in psoriasis. We are probably only at the bottom of this mountain.

Dr McBurney has given me so much to think about. I will follow up with part 2 of our discussion that focuses more on the philosophical and life experience aspects of mindfulness once I wrap my head around it.

neurological path mindfulness default mode network adrenal medulla