As a small animal emergency and critical care specialist, one of the least desirable parts of my chosen specialty is the requirement for shift work, which essentially means working any shift scheduled outside of “normal” working hours. As I become more stubbornly adhered to my early-to-bed and early-to-rise schedule, I find myself less able to stay awake during swing/evening or overnight shifts. It seems that I am not alone as there are several studies investigating methods to increase alertness during swing or overnight shifts. Some of these include sensory stimulation such as bright light, sound, music, or decreased ambient temperature (i.e., everything I’ve done when driving late at night in order to prevent veering off the road), which only function to increase alertness short term. Other options are available, each with their pros and cons, and are discussed in more detail below:
Caffeine is probably the most heavily studied natural pharmacologic intervention and has been shown to consistently improve alertness and the ability to stay awake when consumed during overnight shifts. Most studies have investigated a dose of 2-4 mg/kg, which is the equivalent of 2 cups of regularly brewed coffee for the average person, consumed twice during a shift. While the results are positive, the negative effects of caffeine intake must also be considered including trembling, tachycardia, anxiety, nervousness, digestive disorders, and sleep disruption. Additionally, people adjust to the stimulant effects of coffee, which necessitates repeating or increasing doses and subsequent side effects. For most people, caffeine should not be consumed less than 6 hours before bedtime, in order to reduce interference with sleep. Also, coffee or black/green tea is the preferred caffeine source rather than energy drinks, which often contain very high amounts of sugar, leading to large swings in the glycemic index that can further exacerbate fatigue.
Regular breaks provide pauses for social interaction (e.g., checking in with co-workers) and physical activity (e.g., moving around, stretching) and varying work activities decrease monotony. Both of these techniques are frequently used to enhance alertness and wakefulness during overnight shifts. While some studies suggest these should occur as frequently as every 90-120 minutes, there is little consensus regarding the recommended duration and frequencies of breaks and task changes. Thankfully, veterinary practice (especially emergency work) is already quite variable, so unless you find yourself sitting in front of the computer completing records or doing other monotonous tasks for hours at a time, work activities are usually already varied for us! Even so, taking regular breaks to stand, stretch, breathe, drink water, or watch a funny YouTube video are recommended.
Short rest periods are the most recently studied and strongly advocated method to enhance alertness during overnight shifts. These are typically in the form of naps, which is sleep that occurs during the shift and is 25% (or less) than the duration of sleep after the shift is complete. Naps or short rest periods are often used in anticipation of sleep loss or deprivation in order to sustain alertness during a sleepless period (i.e., before the overnight shift, if possible). Benefits of short rest periods including reducing sleep loss and re-setting the biorhythm, thus counteracting the negative effects of sleep deprivation on the cardiovascular and gastrointestinal systems. Studies demonstrate that the benefits of napping can be seen with as little as 5-20 minutes, but that 1-2 hour naps demonstrate even greater effects. The largest effects on reducing fatigue and enhancing alertness are seen when a nap is taken during the nadir of the night shift (between 1AM – 4AM), rather than at the beginning. A perceived disadvantage of short rest periods is a decrease in “main sleep” after the night shift (although total sleep remains unchanged); however, some people consider this to be beneficial given that more time can be spent doing “daytime” activities. Sleep inertia, which constitutes 10-20 minutes of hypovigilance and performance impairment, can occur upon wakening from a longer nap (> 20-30 minutes), but can be reduced by implementing techniques such as bright light or loud noises upon wakening. Nonetheless, studies suggest that even when sleep inertia occurs, night shift napping is associated with improved performance and decreased sleepiness.
So, what should you ask your boss for during your next staff meeting? How about a new coffee machine and a comfy bed to put in break room?!