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Increasing Alertness on the Night Shift with Exercise

Imagine sitting in a dimmed room, feeling your head nod and sleep waves rushing over you as you monitor a control screen. Should you get another cup of coffee, or should you wheel the exercise bike over and cycle for 20 minutes while monitoring the screen?

Unfortunately, most workers don’t have the option of the exercise bike and would fall back to getting another cup of coffee. But for those night shift workers that have either access to an exercise bike or are able to get in a brisk walk on the job, there are many alertness benefits to some low- to moderate-level exercise on the night shift. In this article, we’ll take a look at how exercise increase alertness on the night shift.

Even low-level exercise causes changes in the body. Movement of the muscles creates different demands on the rest of the body systems as it requires the use of energy sources, an increased oxygen supply, a system to get rid of waste products, and a method to get rid of the heat produced. In order to support the effort of exercising, the heart, blood vessels, nervous system, lungs, liver and skin respond. Exercise prompts the release of adrenaline into the bloodstream, which causes increased brain activity.

Exercise may increase alertness by raising the body temperature of the worker during the overnight period. The body temperature naturally drops by about two degrees Fahrenheit over the nighttime hours in order to induce and maintain restful sleep. By exercising, the body temperature is maintained and perceived sleepiness decreases (Matsumoto, 2002).

The type of exercise performed should be carefully considered, as humans tend to have reduced physical performance during the overnight hours. In particular, balance and hand-eye coordination are reduced, so employees should remember to pay special attention when working out. Exercise bikes or elliptical machines with hand-holds can be easier than treadmills for workers in the nighttime hours. Naturally, individual preferences will vary.

Low- to moderate-level exercise should be encouraged, as it is extremely unlikely that workers on duty have time to overexert themselves. Starting an exercise program slowly will help ease workers into the habit of working out, and supplying information about warming up, cooling down and stretching will promote safe exercise practices. Obviously, all workers should be encouraged to consult their physicians before starting significant exercise programs.

Not only does exercising on the shift create an immediate boost in alertness, improve sleep quality, and speed the transition to the block of night shifts, research has shown that workers who exercise are also more alert the following day after waking from sleep (Yoshida, 1998). This is probably due to the increased sleep quality they had following night-shift exercise. It’s a win-win for the workplace and the family if the health and happiness of the worker improves.

When to Exercise on the Night Shift

When exercising on the night shift, timing is everything. It should be late enough to provide a lasting burst of energy through the difficult early-morning hours, yet early enough that it won’t interfere with sleep later that morning.

In general, sometime after midnight and before the last two hours of the shift is the best time to exercise.  To be more specific, exercising sometime between 12:30 a.m. and 2 a.m. will most likely achieve the maximum effect on alertness while minimizing the worker’s ability to fall asleep that morning.

Company-Sponsored Exercise Programs

Providing exercise equipment at work, such as a stationary bike or treadmill, lets employees who aren’t in the habit of exercising discover its physical and mental benefits – both on and off the job.  These employees may then be more likely to seek out a gym or other exercise facility in their off time.  

Consequently many companies have had success implementing Company-Sponsored Exercise Programs.  For some companies, this means installing an entire exercise facilities, complete with weights and cardiovascular equipment, on site.  

If your company is small or an on-site gym is beyond your budget, you can still encourage exercise by subsidizing gym memberships (which is sometimes possible through one’s health insurance plan), or by allowing employees to take walks or perform other exercise on their breaks.  

Some companies sponsor fitness contests or walk-a-thons, providing rewards to employees who meet certain goals—for example, walking 50 miles in a month.  Others give out free pedometers (available cheaply, especially in large quantities) to encourage employees to walk or jog and track how many miles they’ve accomplished.  Sponsoring a company baseball team (or other sport) is another option to encourage participation in physical activity.

Cost-Effectiveness of Company-Sponsored Exercise Programs

While studies examining the cost and health benefits of company-sponsored exercise programs often group the data with other health and wellness programs, the overall findings are very positive. For example,

  • A 1998 review of work site health promotion (WHP) estimated a Return-Of-Investment (ROI) savings ranging from $1.40 to $3.14 per dollar spent (Goetzel, 2008).
  • A 2001 literature review of seven studies evaluating the financial impact of health-promotion programs reported an average ROI of $3.48 for every dollar spent (Goetzel, 2008).
  • A 2005 review of 56 qualifying financial impact studies conducted over a 20-year span, concluded that participants in work site health programs have 25% - 30% lower medical and absenteeism costs compared with nonparticipants (Goetzel, 2008).
  • Highmark Inc., one of the largest health insurers in the United States, found that for every dollar spent on wellness programs, employers saved $1.65 in health-care expenses (Gannon, 2008).

Some other considerations for company-sponsored exercise facilities or programs:

  • Running or jogging programs tend to be the most cost-effective because they require little equipment.
  • Indirect benefits (often not included in the cost/benefit calculation) can include improvements in absenteeism, productivity, stress, recruitment, retention, corporate image, satisfaction and morale. These are areas where extended hours operations often experience problems.
  • Lifestyle training may be more cost-effective than structured fitness programs.


Exercising on the night shift creates an immediate boost in alertness on the job, and also improves sleep quality at home. Furthermore, allowing exercise at work lets employees who aren’t in the habit of exercising discover its physical and mental benefits.  These employees may then be more inclined to exercise during their free time.  


Goetzel RZ and Ozminkowski RJ. “The Health and Cost Benefits of Worksite Health-Promotion Programs,” Annu. Rev. Public Health 2008. 29:303-23

Joyce Gannon. “Companies offer wellness programs to cut insurance costs,” Pittsburgh Post-Gazette, May 11, 2008.

Matsumoto Y, Mishima K, Satoh K, Shimizu T, Hishikawa Y. Neuroscience Letters 2002 Jun 28; 326(2):133-6. Physical activity increases the dissociation between subjective sleepiness and objective performance levels during extended wakefulness in human.

Yoshida H, Ishikawa T, Shiraishi F, Kobayashi T. Psychiatry and Clinical Neurosciences 1998 Apr; 52(2):139-40. Effects of the timing of exercise on the night sleep.

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