Night Shifts, Long Hours and Fatigue: What OSHA and NIOSH Say Workers and Employers Can Do

Night shifts, rotating schedules and long days keep hospitals, warehouses, restaurants and stores running around the clock. They also make it harder to sleep well. This guide explains what official U.S. sources say about night shift work, long hours and fatigue: what the numbers are, whether any law limits your hours, and what OSHA and NIOSH suggest for workers and employers. It is general information, not medical advice.

In this guide:

• 1. How many people work irregular shifts
• 2. What OSHA reports about shifts and risk
• 3. Is there a law that limits your hours?
• 4. What OSHA suggests employers do
• 5. Sleep tips OSHA gives workers
• 6. NIOSH training on shift work and long hours
• 7. Talking to your employer about your schedule
• 8. Keep a record of your rotation

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How many people work irregular shifts

According to the Occupational Safety and Health Administration (OSHA), almost 15 million people in the United States work full time on evening, night, rotating or other irregular shifts. OSHA describes an extended shift as one more than 8 hours long. So if you work three 12-hour shifts a week or alternate between days and nights, you are far from alone, and the risks of fatigue are a recognized workplace topic.

What OSHA reports about shifts and risk

OSHA's worker fatigue pages say that fatigue is "the body's signal that a rest period is needed" and that long hours may increase the risk of injuries and accidents and can contribute to poor health. The "hazards" page cites several figures from the studies it references:

Source: OSHA, "Long Work Hours, Extended or Irregular Shifts, and Worker Fatigue" (hazards page). These are figures from research cited by OSHA, not predictions for any one person or workplace.

The same page links fatigue to health problems such as heart disease, musculoskeletal disorders, depression and sleep disorders, and says it can worsen chronic conditions. It also cites a 2005 survey of 2,737 medical residents in which each extended shift scheduled in a month raised the monthly risk of a car crash on the commute home by 16.2%. If you are very tired after a shift, getting home safely is part of the picture, so think about a ride or a short rest before driving.

Is there a law that limits your hours?

For most private-sector workers, not at the federal level. The Department of Labor's Wage and Hour Division states that the Fair Labor Standards Act (FLSA) has no limit on the number of hours employees aged 16 and older may work in a workweek. The FLSA is a pay law: covered, non-exempt employees get overtime at one and one-half times the regular rate for hours over 40 in a workweek. (Details are in our guide to shift work and overtime pay in the U.S.)

OSHA's pages do not point to a specific standard on work hours or fatigue; they say that employers must take measures to monitor and limit worker exposures under the Occupational Safety and Health Act, and they present their fatigue material as guidance. Limits on how long you can be required to work, or on rest between shifts, usually come from somewhere else:

• State law, for example limits on mandatory overtime for health care workers in some states (see our guide to health care 12-hour shifts and mandatory overtime).
• Local law, such as the fair workweek rules that give some workers a right to rest between shifts (see clopening and rest between shifts).
• A union contract or employer policy.
• Industry-specific rules, which exist in some sectors. If you work in one of them, check your own agency or employer materials.

Whether any of these applies to you depends on your state, city, industry and employer.

What OSHA suggests employers do

OSHA's prevention page lists measures that employers can take. These are recommendations, not legal requirements:

• Review staffing. Look at workload, work hours, understaffing and scheduled and unscheduled absences, since they all contribute to fatigue.
• Plan schedules for rest. OSHA mentions arranging schedules "to allow frequent opportunities for rest breaks and nighttime sleep."
• Adjust the environment. Lighting, temperature and surroundings can affect alertness.
• Train workers. Topics include the hazards and symptoms of fatigue, sleep, diet, exercise and stress management.
• Consider a fatigue risk management plan, treating fatigue like other workplace risk factors.

Sleep tips OSHA gives workers

The same page lists sleep habits for workers. In short:

• Aim for 7 to 9 hours of sleep a day, without interruptions, at a consistent time.
• Avoid caffeine before bedtime.
• If you work evenings or nights, make sure you have slept within the 8 hours before your shift.
• If you nap before work, OSHA suggests keeping it under 45 minutes or over 2 hours so that you complete a full sleep cycle.
• Keep your sleeping area comfortable, cool, dark and quiet.
• If you have trouble sleeping, keep a sleep diary and talk to your doctor.

These are general suggestions from OSHA. For health concerns about your sleep or your schedule, talk to a health care professional.

NIOSH training on shift work and long hours

The National Institute for Occupational Safety and Health (NIOSH), part of the CDC, offers a free online training for nurses and their managers on shift work, long work hours and fatigue (NIOSH Publication No. 2015-115, revised October 2023). It has two parts: the first explains the risks and why they occur, including fatigue, sleep and circadian rhythms; the second covers personal behaviors and workplace systems that reduce those risks. It was written for nursing, but the ideas are useful for anyone on rotating or night schedules.

Talking to your employer about your schedule

• Be specific. "Two night shifts followed by an early start" is easier to act on than "my schedule is hard."
• Ask for patterns, not exceptions. Many workplaces can offer fixed rotations, forward-rotating shifts or a set number of nights in a row. Ask what is possible.
• Check your contract or handbook. Limits on consecutive shifts and rest periods are often there.
• Know where to ask. For pay questions, contact your state labor department or the DOL Wage and Hour Division. For safety concerns, OSHA or your state occupational safety program.

Keep a record of your rotation

Fatigue builds over a run of shifts, not just one. It helps to see how many nights are in a row, how long you have between shifts and how your days off fall. A record of your schedule is also useful if you need to discuss it with a manager or a union representative.

Shift2Cal keeps your schedule in one place. Take a photo, or upload a screenshot, PDF or CSV of your schedule; the AI reads the shifts, you check and correct them in a preview, and they sync to Apple Calendar, Google Calendar or Outlook. If your rotation repeats, save it as a recurring pattern and see your nights, days and rest days in your calendar at a glance. Shift2Cal does not calculate pay, give health advice or check whether a schedule is legal, and processing happens on your device.

Related: Paid Sick Leave for Shift Workers: Federal, California, Washington and New York State Rules.

Sources, all read on November 6, 2026:

• OSHA, Long Work Hours, Extended or Irregular Shifts, and Worker Fatigue (page shows no revision date).
• OSHA, Worker fatigue: hazards (no revision date shown).
• OSHA, Worker fatigue: prevention (no revision date shown).
• CDC Stacks, NIOSH Training for Nurses on Shift Work and Long Work Hours (NIOSH Publication No. 2015-115, revised October 2023).
• U.S. Department of Labor, Wage and Hour Division, Wages and the Fair Labor Standards Act (no revision date shown).

This article is general information, not legal or medical advice. Whether any limit on hours or rest applies to you depends on your state, city, industry, employer and any union contract, and rules change. For a specific situation, contact your state labor agency, the U.S. Department of Labor's Wage and Hour Division at 1-866-487-9243 (1-866-4USWAGE), OSHA, a union representative or an employment attorney. For health questions, consult a health care professional.