Shift work and health: the Cliff notes.

I’ve worked in a wide variety of jobs in my life. Like many people, I spent the latter part of my high school and university years cleaning toilets, clearing tables, washing dishes, delivering pizza and making sandwiches when there was only one sandwich maker in town. Subway, George St. Aaah….the memories. Somehow I was always put on the graveyard shifts of Thursday night 8pm-4am and Saturday 10pm-6am. Though it totally went against my natural tendency to be early to bed, early to rise, they were the most fun shifts to work. As one of the few places open 24 hours over the weekend, we got queues out the door of students either rolling in from the Cook or stumbling home from KCs, with the busiest period being from 2.30am to around 4am. I still remember the excitement at serving both a glazed eyed Marc Ellis and Rachel’s brother Jonathan from Shortland Street – before seeing Shorty stars was as ho-hum as …. seeing Shorty stars. Anyway. I’d get home either 4.30 or 6.30 and sleep 5ish hours before getting up and try to get back into a daytime routine. I always felt rubbish through lack of sleep and so thankful that I wasn’t pursuing a career that required me to do shift work.

Now, though, amongst the industries that have always needed to be available 24/7, the global society we live in now necessitates other occupations to put in hours that extend beyond the 9-5. The prevalence of employees working shifts in the media, healthcare industry, on the front line and in the corporate world is estimated to be around 20% and the available data in New Zealand is in line with this. This is a large subsection of the working population, and why it’s of note is that there are well established links between shift work and poorer health outcomes – both short and long term. The constant sleep deprivation that results from shift work is a major underlying issue.

The most important things we can do to help mitigate the effects of chronic sleep deprivation that occurs due to shift work (aside from actually sleeping!) are the very things that go out the window. A regular exercise routine is more difficult to maintain, due to tiredness from lack of sleep or the inability to structure if you are on a shift cycle that changes from day to night. Eating healthily is more difficult as having motivation to plan and prepare is more challenging, and often the pull to higher sugar, poorer nutrient foods is governed by cravings and accessibility. In addition, perhaps overlooked, maintaining relationships can be more difficult as the non-sociable hours of shift work impact on our availability to spend time with friends and family. Hanging out with John on the 5th floor is not the same.

It’s also well established that the affects on circadian rhythm put shift workers at a higher risk of many chronic diseases. Up until 150 years ago we were constrained by the natural sunrise and sunset and life on earth had evolved according to this. When artificial light was invented there were suddenly more hours in the day that could be spent being awake, and the shift in our wake and sleep cycle impacts on metabolism, hormones, digestion, cardiovascular system; in fact all of our cells in our body is affected by this. Sleep deprivation in the short term increases insulin resistance – it takes just a single nights’ sleep for this to occur. There is an increase in the risk of injuries on the job, and a link between both acute and chronic gastrointestinal problemsMood disorders are also associated with circadian rhythm disruption, and both observational and experimental data point to an increased risk of obesity in shift workers due to these circadian rhythm changes.  Over the long term, there is an increased prevalence of risk factors associated with the metabolic syndrome, type 2 diabetes, cardiovascular disease and cancer are all seen in shift workers compared to those who keep a more normal work schedule.

While you might think people who are early risers would be more negatively affected by shift work, this hasn’t been found to be the case.  Research shows that those who are late risers have lower levels of melatonin (a hormone that mediates the sleep-wake cycle); the suppression of which is one proposed mechanism for the increased health risks associated with working hours that disrupt circadian rhythm.

So what to do? Obviously, being able to opt out of shift work is not realistic for the 20% of the population who live and work in this 24 hour society. This report details the interventions in the research setting that have been found to be most beneficial. These include scheduling shifts to be ‘forward’ shifts rather than backward shifts (i.e. moving from a morning, to an afternoon, to an evening shift), avoiding stimulants such as coffee (in excess) and wearing light blocking eyeglasses on the way home from night shift. Sleeping in a dark room and wearing an eye mask will also help.

Along with the above, ensuring good sleep hygiene practices through both diet and exercise are essential. Though it might be the last thing you feel like doing if you’re just getting into exercise, a routine that you stick to will go a long way to helping you mitigate these effects. Exercise is so important for everyday health and well being, that to ignore it would only further exacerbate some of the health issues mentioned above. Further, in the face of sleep deprivation and acute insulin resistance, strength training helps improve insulin sensitivity and may minimise the blood sugar disruptions experienced. As mentioned, coffee is likely one of the first things you go to when you feel like you need an energy hit, but instead of this, why not try green tea – it has L-threanine in it which helps keep you alert without the caffeine hit. Perhaps save coffee for your days off (and limit to just one); dare I say it – try a decaffeinated brand otherwise. Some companies like to supply food for their employees, and this tends to be cheap plain biscuits, white bread and jam, and other types of food to provide a quick hit of energy when time is of the essence and there is no time to stop for a real meal. These options, along with the vending machine, are the last foods you want to be eating. On your off days make it a habit to prepare two or three ‘dinner’ like meals that you can freeze and eat throughout the week. Trying to structure your whole food, minimally processed meals so they are ‘dinner’ like at dinner time (before you head into a night shift, perhaps), lunch like in the middle of your shift, and then a lighter meal before you hit the sack in the morning will maintain the regularity of meals regardless of whether you’re working or not. Being prepared with your good food options means you can avoid those that are available at work. In addition, a magnesium supplement (with an amino acid or citric acid chelate) before bed can help promote good sleep. Finally, if you are constantly waking up, practicing some deep breathing in bed can help calm you down and send you back to sleep. Diaphragmatic breathing will decrease your sympathetic nervous response – ‘fight or flight’ and the levels of stress hormones entering the bloodstream which are released because of this which could prevent you falling easily back to sleep.

Shift work is a necessity for many people, and some fare better than others. If you are a shift worker who fares fairly well despite the disruption in sleep and subsequent poor lifestyle habits you may not feel that these tips would apply to you. However maintaining your health is as important now to offset the long term effects of shift work.

Feeling SAD?

Damn. We Aucklanders are getting our share of terrible weather. That’s the problem with being smug and posting pictures of our awesome non-winter winter climate… eventually it comes back to bite us in the butt. Usually in spectacular fashion: this week has been almost torrential storm-like conditions, with power outages and garden furniture strewn across the driveway (or is that just me?) Naturally this dip in temperature to below 15 degrees comes with it a sense of gloom as the sun fails to make an appearance. Grey clouds are oppressive, huh? Does that make you feel a bit blue? It does me – once the temperature drops and I haven’t seen the sun in four days I feel utterly miserable, diagnose myself with mild depression, and more specifically Seasonal Affective Disorder – or SAD. It’s a particular type of depression that starts in the autumn and doesn’t let up until the daffodils are out. In reality, I don’t think I would be diagnosed with SAD, and population prevalence is in the realm of 1-12% depending on your location, a higher prevalence in areas with longer winter days and lack of sunlight hours (one reason why I couldn’t live in ‘middle England’; not only does it sound horribly dull (it’s up there with ‘original flavour’) but daylight hours are limited during winter. And I know it’s worse elsewhere). But I digress. However, I feel a bit blue all the same.

Interestingly, there are two types of seasonal affective disorders – some curious people feel more depressed in summer than they do in winter, therefore the reverse is true. That to me is like a fate worse than death, quite frankly. Up there with Man Flu. SAD is diagnosed by the presence of symptoms such as: 

  • Decreased energy levels
  • Difficulty concentrating
  • Fatigue
  • Increase in appetite
  • Increased desire to be alone
  • Increased need for sleep
  • Increased irritability
  • Increased anxiety
  • Weight gain

Scientists have pinpointed a few reasons why the lack of sunlight can disrupt our mood. This is largely due to our levels of melatonin – this is a hormone which plays a role in how our body regulates its sleep/wake cycle. The longer periods of darkness in the winter months may stimulate melotonin production and potentially people with SAD overproduce melatonin or are hypersensitive to melatonin in the winter months. While melatonin is recommended on an infrequent basis for people who struggle with sleep (for example, during periods of travel where jetlag can set it), too much melatonin can result in headaches, day time sleepiness, and depression.

Other evidence shows that decreased levels of neurotransmitters (chemicals that transmit signals between nerve cells) such as serotonin or dopamine may also play a role in triggering SAD. Low levels of serotonin in particular have been associated with carbohydrate cravings in people with SAD, and with sleep disorders and depression in the population at large. So not only does the reduced amount of serotonin trigger carbohydrate cravings (carbohydrate facilities the production of serotonin), this subsequent increase in food intake can lead to weight gain and further feelings of despair. Lose-lose, really. Even in those that don’t feel particularly blue during winter, the stodgy, starchy carbohydrates that can lead to weight gain and increased carbohydrate cravings are the warming foods we naturally gravitate towards.

As serotonin is largely produced in the gut I went searching for studies that looked for a link between digestion and SAD, as without the nutrients required to produce serotonin – including tryptohan which is an amino acid and key in the process – levels will be lower. I didn’t come up with any though, but with the clear link between the gut and brain, it makes sense that there would be.

Lastly I also found interesting relationships between SAD and other conditions. It’s not just weight gain that could be a problem – A Finnish study found there was a significant association between seasonal changes in mood and behaviour and metabolic syndrome, with risk of metabolic syndrome increased by 56% in those with seasonal affective disorder. The researchers noted that the metabolic syndrome is related to changes in the circadian rhythm – and that circadian, sleep-wake and seasonal cycles may each be regarded to reflect an intrinsic metabolic cycle. Sleep onset is a switch for the metabolic and cell repair systems from daytime to night-time settings and if the right signals aren’t there, the circadian clockwork relies more on the metabolic cycles producing time-giving signals needed for adaptation – insulin plays a role in this and helps set the circadian rhythm.

So what treatments exist for helping improve melatonin and serotonin levels and hopefully offset the low level depression that many people experience?

Light therapy: helps with regulating melatonin production and can indirectly affect serotonin levels by blocking the mood-lowering affects of acute tryptophan depetion. exposure to intense light in the early morning has been found to be most effective, as this suppresses melatonin. The treatment involves sitting in front of fluroscent lights which are installed behind a diffusion screen, and carrying out normal activities for anywhere from 30 min to 2 hours depending on the intensity of lights. The critical factor is that the light matches that of either early morning or just before sunset. he dosage most often found to be effective is 5,000 lux per day, given as 2,500 lux for two hours or 10,000 lux for 30 minutes. This isn’t just sitting in front of a desk lamp.

I talk about sleep all the time… but in addition to adequate sleep, getting up and going to bed at around the same time most days can also help regulate levels of melatonin, particularly combined with the light therapy as above.

Get outside and exercise: it might be the last thing you feel like doing but honestly – nothing is as energising and invigorating as getting outdoors, particularly in cold, windy, inclement weather. This helps boost serotonin levels by increasing availability of tryptophan to the brain. This is particularly important as we tend to spend a lot of time inside. The added bonus here is getting natural light – this helps boost overall mood.

Fight against the desire to stay at home and make plans with friends or family. It’s all too easy to hibernate, inevitably making you feel worse.

Diet: while there are foods that are high in serotonin or tryptophan, few actually cross the blood brain barrier to enable their action in the body to improve mood. Typically high protein foods containing tryptophan were recommended, though this doesn’t actually increase serotonin levels in the brain when studied  , as amino acids compete for transportation in the body and most protein containing foods are relatively lower in tryptophan than other amino acids. Hence perhaps changing the ratio of tryptophan to other amino acids is useful, and research has shown that supplementing with a dietary protein alpha-lactalbumin (a constituent of milk) can increase serotonin through this strategy. While interesting, it’s not very practical for people in every day life. Insulin helps set the circadian rhythm and perhaps a diet that focuses on high protein for breakfast and lunch, with small amounts of carbohydrate at night can maximise insulin secretion at night and help appropriately reset circadian rhythm. Unsurprisingly, the importance of a whole food diet rich in nutrients to support digestion and absorption of nutrients cannot be overstated given the link between serotonin and mood.

Oh, and hopefully the increased protein, the exercise and the sleep helps you combat those carbohydrate cravings. In addition to this, find some equally warming winter substitutes. It’s not like you need to completely avoid carbohydrates at all (see above re insulin) – it’s about avoiding Richard Dreyfuss amounts of the white stuff. That’s not going to make you feel any better I promise.

  • Mash: cauliflower mashed with butter or olive oil, herbs and seasoning.
  • Fries: slice swede and boil until a little bit soft. Dry off and coat in coconut oil and some almond flour and roast. Or just roast from raw.
  • Pasta: zucchini noodles (or as my friend Helen likes to call them: courgetti) or use leeks (cook)
  • Rice; cauliflower rice

There are certainly people who are diagnosed with SAD, and equally there are people (like me) who wouldn’t meet the diagnostic criteria yet still feel a bit less awesome. All of the above tips then will help you keep feeling awesome over the winter months. And we are almost half way through! That’s enough to make me feel happier :-).