Shift Work: What Are the Health Risks?

As the song goes, “Workin’ 9 to 5, what a way to make a livin’,” but for many people, shift work is the better way to go. Shift work encompasses working hours outside the extended 7 am to 6 pm timeframe. 

Some people work rotating schedules, split shifts, or evening schedules. Gone are the days when 8-hour workdays are the norm. Required lunch breaks (up to an hour) can transform the workday to 9 hours. Add in commute time, and some people can easily claim 11 hours of their day associated with work (when commuting takes an hour each way).

Why is shift work necessary?

Not every job is a 9 to 5 requirement. Many professions function round the clock, requiring people to work outside the “normal” daytime schedule. 

The Bureau of Labor Statistics divides shift work schedules into Evening, Night, and Early Morning hours. We break down some of the positions that operate during these times and a general idea of workers in these categories:

  • Evening Shift: 6 pm to 10 pm
  • Retail workers, including sales and cashiers
  • Performers, including on-stage, on-air, and behind-the-scenes workers
  • Athletes and others affiliated with sporting events and facilities
  • Personal care workers, including hairdressers, massage therapists, personal trainers, and salon workers, 
  • Food industry staff, including servers, bartenders, cooks, and supporting workers
  • Telephone customer service support – many industries
  • Travel workers, including TSA and other airport employees
  • Health and veterinary personnel at clinics staying open late
  • Transportation workers, including taxi and ride-for-hire drivers, bus drivers, truck drivers, and train conductors
  • Cleaning crews
  • Night Shift: 11 pm to 3 am (also encompasses 11 pm to 7 am workers)
  • Medical personnel, including doctors, nurses, hospital employees, and paramedics
  • Veterinary personnel at all-night emergency care centers
  • Police, firefighters, security guards, and other protective fields
  • Transportation personnel, including all those listed during the evening shift
  • Assembly line workers in manufacturing and food preparation
  • Cleaning crews
  • Road repair crews
  • Early Morning Shift: 4 am to 8 am
  • Farm, forestry, and fishing workers
  • Construction fields, including architects, engineers, roofers, carpenters, electricians, plumbers, equipment operators, and other workers
  • Mechanics and repair personnel in many fields
  • Restaurant personnel
  • Medical personnel

Of course, these are only partial lists of people who work these hours. Many of the fields listed in one category easily carry over to others. 

In addition, there is also an afternoon shift which runs from around 3 pm to 12 am (or other such timeframes). Many fields, such as police and hospital workers, have round-the-clock eight, ten, or twelve-hour shifts. Rotating schedules can have a person working days one day, nights the next, or alternate weeks of days and nights. 

Some people who do shift work have set schedules, allowing them to plan their routines and days off accordingly. Split shifts are frequently seen in businesses such as restaurants, where employees are needed for busy periods, such as lunch and dinner. It is not unusual for these workers to take a break at midday before returning to work. 

Shift working makes it difficult for many people to get into a routine, which can lead to sleep and health disorders. It becomes essential for those who have rotating or on-call shifts to schedule their sleep accordingly.

How Many People Are Shift Working?

According to a 2020 report, approximately 26% of employed adults in the US were non-day shift workers. That number is staggering as those not working traditional daytime hours will likely get less sleep, increasing the risk of accidents and health issues. Interestingly, caffeine intake does not seem to increase with those who work night shifts over day shifts. 

While the numbers vary depending on the report, individuals working the “graveyard” or third shift make up around 3.2% of the US workforce. This category includes healthcare, public service, factory, and transportation workers. 

The US Bureau of Labor Statistics puts the number of people working shift schedules at approximately 16% of wage and salary employees, with 4% working nights and 6% working evenings. 

However you look at it, millions today work outside the typical 9 to 5 shift. The reasons vary, including:

  • Easier commute times when fewer people are on the road
  • Better for family life and childcare
  • Increased wages for shift work in some professions
  • The necessity of having days available for medical care or other responsibilities
  • Some people are night owls and prefer working at night
  • Others are early risers who work better before the sun comes up

There is a reverse side to shift work, as it can also limit family and socializing time, necessitate the need for the home to remain quiet during the day so the worker can sleep, and lead to more car accidents that occur between midnight and 6 am when people are often tired or driving under the influence. 

Can Shift Working Cause Health Risks?

Shift working can lead to health problems because the body requires between 7 and nine hours per night of quality sleep to repair and rejuvenate the body. Metabolism of the day’s food intake, cellular repair and replenishing, cognitive processing and storage of the day’s information, critical hormone production and usage, and immune strengthening occur during sleep. 

Not getting enough sleep can interfere with these areas, increasing the risk of certain health conditions. Fatigue can also affect work performance, mood, relationships, and quality of life. 

Some people adjust easily to shift work, while others do not. For those who do not, finding a better schedule that allows their bodies to function optimally is often recommended. 

While health concerns are a significant issue for shift workers, so are relationship and family problems, including divorce. The anti-social aspect of shift work can lead to more responsibilities falling on one partner, increasing stress in a relationship. 

Individuals must also avoid alcohol, drug, or stimulant abuse. These substances can become habit-forming and hazardous to one’s health.

Health Risks Associated with Shift Work

Shift work interferes with the body’s natural circadian rhythm, affecting crucial functions, including digestion, metabolism, immunity, endocrine hormone balance, cognitive processing, and the cardiovascular system. Sleeping during the day and staying awake at night goes against the body’s natural physiological state, causing considerable stress on physical, emotional, and cognitive processes. Rotating shifts cause the most problems as the body does not have the opportunity to get used to one set schedule.

The following health disorders have been studied extensively in association with shift work and sleep disorders:

  • Weight gain and obesity

Metabolic syndrome is associated with high triglycerides, blood pressure, cholesterol, and fasting blood sugar levels. Most people with this condition are significantly overweight. Shift work often interferes with proper nutritional profiles, leading to weight gain and obesity. Sleep plays a crucial role in obesity, as that is when human growth hormone (HGH) and testosterone production stimulate the metabolism to convert food into fuel and process it for energy. Getting less than six hours of sleep often leads to weight gain. Type 2 diabetes risk also increases with shift work. 

  • Cardiovascular disease

Studies have shown shift workers to have a 40% increased risk of developing ischemic heart disease over day workers. Increasing those risks is a more likelihood of poor nutrition, smoking, obesity, high blood sugar, and lack of sleep. Shift workers tend to smoke more than day workers. 

  • Mood changes and mental diseases

Disruption of the circadian rhythm leads to sleep deprivation, anxiety, increased stress, nervousness, irritability, depression, neuroticism, and other mood disorders.

  • Gastrointestinal problems 

Two to three times the amount of shift workers complain about digestive problems than day workers. Normal circadian rhythm affects more than sleep as it also has regular phases in gastrointestinal functions. Digestion difficulties, pyrosis, flatulence, peptic ulcer, irritable bowel syndrome (IBS), and other gastrointestinal troubles increase in shift workers. 

  • Cancer

Circadian disruption has also been shown to be possibly carcinogenic to humans, according to the International Agency on Research on Cancer (IARC). Breast cancer in women was one of the most problematic areas noted. Because endocrine changes occur on multiple levels in shift workers, including melatonin suppression and sleep deprivation, immune suppression may occur, allowing for the development and growth of malignant cells. 

  • Women’s concerns

Disruption in a woman’s menstrual cycle may occur with shift work, altering the cycle, increasing premenstrual syndrome and pain. Women may be at a higher risk of miscarriage, impaired fetal development, low birth weight, and post-term birth. 

Not everyone can tolerate shift work, and people over fifty, those with chronic respiratory disease, type 2 diabetes, heart trouble, neurological issues, high blood pressure, and individuals using pharmacological therapy that is time and food-restricted are among those who may not be ideal candidates for night work. 

General Advice on How to Get the Required Rest

If you live with others, everyone must understand your need for sleep. Posting your work schedule for everyone to see helps to eliminate scheduling dilemmas. Do not sacrifice your well-being to make others happy. It is essential that you get the rest you need to protect yourself from other problems down the road. 

Here are some steps to take:

  • Get enough sleep

Make sure you get between 7 and 9 hours of sleep each night. Get blackout curtains or blinds to darken your room, use a sleep mask if necessary, and lower the temperature to 65 degrees for optimum sleep. Do not fall asleep anywhere other than your bed. Use a white noise machine to block out sounds during the day. Try to get on a sleep cycle where you go to sleep and wake at the same time each day. 

  • Turn off your phone and other electronics

Give yourself at least half an hour of electronic-free time before bed. 

  • Unwind with movies, painting, music, or reading 

These activities allow our mind to relieve anxiety and separate from the day’s (or night’s) stressors. Letting your brain relax helps increase general energy levels. Discover other ways to increase energy levels and overcome fatigue.

  • Have a warm bath or shower

A warm bath (especially with Epsom salts) or a shower can help calm your body and prepare it for sleep. 

  • Avoid bright lights

Daylight blocks melatonin release, so avoid spending time in sunlight before going to sleep. Wear dark sunglasses while driving or outdoors.

  • Exercise

Regular exercise can help you avoid weight gain and promotes hormone release that can lower stress levels and aid with sleep. 

  • Avoid alcohol, caffeine, sugar, and fried or heavy foods

These items interfere with allowing the body to drift off into restful sleep. If you are hungry, try having a banana with nut butter or some turkey before sleeping. 

  • Schedule your activity beforehand 

Let people know when you are available and preplan so that you can ensure you get adequate rest. Most importantly, schedule time for yourself. Communication with others is crucial.


Shift work is a necessity in many fields. It can benefit families with young children to allow one parent to be home when needed during the day. However, it can also strain a relationship and one’s health.

Taking steps to ensure you get proper sleep and nutrition to protect your health is vital. If you have trouble sleeping, contact your doctor for help. However, avoid using sleeping aids as that can cause long-term problems.