Shift Work & Health Series Overview

Written by Coach Randi Levendusky


Anyone else work 12 hour shifts multiple days in a row and have a tinge of dread the night before the first shift because you know that no cleaning or proper adulting will occur outside of work for the next few days (and your life can be best summed up as something similar to that of the aftermath of a tornado)? 

It me.

But there is science behind why we feel so burnt out after working irregular shifts that is quite interesting!

Statistics reveal the majority of the working society is working irregular shifts! Such as: rotating shifts, night shifts, weekends, or shifts longer than 8 hours. 

Shift work is meant to be a good thing. It leads to production/services being performed 24 hours a day, shift differential pay, and increased employment.

 However, shift work does come with a price – health.

If you look in the dictionary, the definition of health is to be without sickness. While this may be the written definition, we need to keep in mind that health has multiple dimensions- physical, social, emotional, and psychological. 

Shift work disrupts our sleep, our natural circadian rhythm, brings chaos to our hormone profile, and in turn has the ability to negatively affect each and every one of these dimensions.

Let’s take a closer look at the science behind shift work and health.  


Circadian Rhythms and Sleep Disorders:

You know that feeling after working crazy hours… 

The one were you think you might actually throw-up, sleep for the next three days AND still feel dead to the world.

Yeah, there is a name for this. It’s called Shift Work Sleep Disorder. It occurs when your circadian rhythm is interrupted. It’s characterized by excessive daytime sleepiness and insomnia. 

When I say Shift Work Sleep Disorder, I am not referring to the crappy feeling you get on your first nightshift, when you’ve been up all day and take a power nap before work to flip your schedule. 

Shift Work Sleep Disorder is an ongoing issue.

Symptoms of Shift work sleep disorder:
Excessive sleepiness and drowsiness
Insomnia and the inability to stay asleep 
Lack of energy
Mood swings, irritability, depression, and anxiety
Poor concentration


Gastrointestinal issues

It is unclear whether shift work can lead to persistent sleep disorders. However, The International Classification of Sleep Disorders has officially defined Shift Work Sleep Disorder as one that “consists of symptoms of insomnia or excessive sleepiness that occur as transient phenomena in relation to work schedules” (Costa, 2010). This disorder can be diagnosed based on an individual’s history, polysomnography, and the Multiple Sleep Latency Test.

Completely flipping, or even slightly manipulating, your sleep/wake cycle, carries over into changes in your rest/activity pattern, this is a HUGE stressor on your body and its ability to function appropriately. 

Staying awake at night, and sleeping during the day goes against our natural inner clock, also known as our circadian rhythm. It forces your body to adjust it’s psycho-physiological state because you are now completing activities at night that normally would be completed during the day, and vice versa. 

Our bodies are able to shift its functioning and rhythm by ONE HOUR per day. 

Yeah, you read that right- your body adjusts to shift change at the rate of ONE hour per day. You know those days you switch from a complete day person to a night person in less than 24 hours? Now you can understand why your body is completely exhausted, it was not meant to flip sleep/wake cycles that quickly! 

Now imagine if you’re not a permanent night shift worker, you work rotating shifts. Your body never has time to adjust to a new wake/sleep cycle because you are constantly having to flip your schedule back and forth. 

This manipulation of your circadian rhythm and daily body functions is responsible for the “jet-lag” like feeling you get. Symptoms include “feelings of fatigue, sleepiness, insomnia, digestive troubles, irritability, poorer mental agility, and reduced performance efficiency” (Costa, 2010).

When we operate against our biological “clocks” sleep quality and quantity suffer. Many night shift workers try to sleep right after work. This means the shift worker is trying to fall asleep and stay asleep while normal biological cues are telling the body to wake up! – making falling asleep and staying asleep a real challenge. This can cause 2-4 hours of lost sleep, resulting in poorer stage 2 and REM sleep, leading to less restorative sleep, aka you can sleep all day and still feel like a zombie when you wake up. This sleep deficit causes increased drowsiness in the last half of the night shift, and increases the risk of work errors.


Psychological and Mental Health:

Not only does shift work disrupts our sleep, but this sleep disruption has a significant impact on our mental health and mood. 

Chronic disruption in circadian rhythms and sleep deficits lead to fatigue, mood disorders, and elevated anxiety and depression. Shift work schedules are the opposite of the body’s normal hormone fluctuations, causing shift workers to commonly complain of irritability and nervousness related to stressful work conditions. This leads to increased work absences. Often times, shift workers are prescribed anti-anxiety/anti-depressant medications to aid with the mental health struggles caused by shift work. 


Gastrointestinal Disorders:

Sleep disturbance is the number one complaint of shift workers, but gastrointestinal disorders take a close second. Nearly 75% of shift workers experience a change in their gastrointestinal health. 

These gastrointestinal disturbances are related to the irregularity of mealtimes and normal circadian phases of gastrointestinal functions which include the excretion of gastric, bile and pancreatic secretions, enzyme activity, intestinal motility, rate of absorption of nutrients, and hunger and satiety hormones. 

Mealtime is another influencer for our biological functions. Shift workers typically do not alter their calorie intake, but rather the timing of when their calories are consumed. Shift workers also have a tendency to alter their macronutrient intake, including increasing their carb and fat intake, and decreasing protein intake. 

Common gastrointestinal changes noted by shift workers include constipation, difficulties in digestion, flatulence, peptic ulcers, and irritable bowel syndrome. A Japanese study found shift workers in comparison to their day shift counterparts are at twice the risk for developing peptic ulcers, TWICE THE RISK! 


Metabolic Disorders:

Common metabolic disorders seen in shift workers include abdominal obesity, increased triglycerides, reduced HDL-cholesterol (the good cholesterol), high blood pressure, and increased fasting glucose. 

Why are metabolic disorders such a concern? They can lead to type 2 diabetes and cardiovascular diseases. 

These changes in cholesterol levels, blood pressure, and fasting glucose are related to numerous factors such as the misalignment in circadian rhythm, poor sleep, digestive disturbances, changes in daily lifestyle -like meal timing and food composition, and elevated stress levels. 

Shift workers may also experience increased insulin resistance that naturally occurs at night- our bodies just were not designed to eat honey buns at 1am, meaning the body is not able to adjust to increased glucose levels due to carb consumption late at night, causing elevated blood sugars. This insulin resistance places shift workers at NEARLY TWICE THE RISK of developing type 2 diabetes.


Cardiovascular Disorders:

A review of 77 studies, found shift workers to be at a 40% INCREASED risk for ischemic heart disease compared to day shift workers. This increased risk is likely due to the alteration in circadian rhythm, which in turn causes disruption in the cardiac autonomic control patterns (aka our hearts natural functions). Partner this with reduced sleep, elevated stress, work/family conflicts and you have the perfect formula for heart disease.  

It has also been reported that major cardiovascular risk factors: smoking, obesity, and elevated cholesterol are more prevalent in shift workers. Studies have found smokers showed an increase in the number of cigarettes they smoke per day when working shift work hours, and non-smokers who switch to shift work find it easier to start smoking.


Women’s reproductive function: 

The female menstrual cycle is another hormonal rhythm that can be disrupted by shift work. 

Female shift workers have reported higher incidences of altered menstrual cycles, premenstrual syndromes, menstrual pains, miscarriage, and impaired fetal development including pre-term birth and low birth weight. Studies have found working rotating shifts that include night shift, to be a higher risk factor for miscarriage than other traditional physical factors such as lifting heavy objects. 


Social Problems:

Shift work may also result in psychological stress and psychosomatic disorders due to its interference of family and social life. 

Many family events and social gatherings are organized around day shift work schedules. For families with shift workers, attempting to coordinate the schedules within a family becomes difficult due to work schedules, children’s schedules, and personal needs/responsibilities.

Feeling the pressure of not having enough time in the day and work/family conflicts are a common issue for shift workers, especially those who have other commitments such as continuing education or children. These stressors can have a negative influence on marriages, parental roles, and lead to increased sleep problems, fatigue, and psychosomatic complaints. 


Now that I just dumped all the negatives of shift work on you, you’re probably wondering what you can do to counteract these health concerns!

DO NOT FRET! Here’s some key tips I’ve learned during my career as a night shift RN:

  1. Prioritize sleep: Don’t try to cram all of your errands in one morning after a night shift, stay up until noon, and then go back to work at 7pm! Instead, develop a night time routine and follow it. Repeating your night time routine signals to your body it is time to slow down and rest. This may be coming home, showering, eating a small snack, reading for ten minutes, and then sleeping. Whatever it is, do it every morning before bed. 
  2. Nutrition is key: We learned shift work can lead to nutritional imbalances, such as consuming more carbs and fat, and less protein. Start paying attention to what you eat, try writing it down for a week, and then analyze it. Are you eating whole foods or processed food? Are you eating protein – and no peanut butter is not a protein source. Struggling in this area? Consider a nutrition coach – work with us at RISING TIDE PERFORMANCE!
  3. Earn your training: Night shift is not the time to up your gym volume or intensity. Shift work is a significant stressor on its own. Adding higher intensity in the gym will propel your body deeper into the stress response and raise stress hormones like cortisol. Hit high intensity workouts once, maybe twice a week, and fill in the rest of the week with either aerobic work (running, biking, swimming) or traditional weight lifting (squats, bench press, deadlifts).
  4. Pay attention to what your body is telling you: Are you constantly exhausted? Are you missing periods? Are you irritable? These are all signs your body is stressed, and begging for help. 

Stay tuned! – Throughout this shift work series, I will be going more in-depth on how to manage the stressors of shift work, improve your sleep, and how to improve your gym performance all while working crazy hours! 


(2010). Shift work and health: current problems and preventive actions. Safety and health at work, 1(2), 112-23.



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