November 16, 2016 10:14 PM EST
Overnight shifts have always been the bane of my veterinary career, starting as a student when I was required to work overnight emergency shifts and continuing on through my small animal rotating internship and emergency and critical care residency. And it seems like the older I get, the less of a “night person” I am – very clearly a lark rather than an owl! Human nature would suggest that I am not alone; people are diurnal, which means that they tend to sleep during the night and stay awake during the day. Unfortunately, night shifts disrupt this circadian rhythm making wakefulness and consolidated sleep difficult to achieve.
The circadian rhythm relies on synchronizers to maintain a normal cycle, the most powerful of which is light, which affects the secretion of hormones that stimulate sleep (e.g., endogenous melatonin). Other stimuli such as exercise and exogenous (over-the-counter) melatonin can also have an effect, although most studies demonstrate that these have less of an impact. If you are a shift worker who is scheduled for overnights, there are certain things that you can do in order to help regulate. Follow these researched tips in order to manage difficulties adjusting to working nights:
- The sleep-dark period should be strived for as soon as the shift is complete. This can be implemented by wearing dark sunglasses outside after the shift and using black-out blinds in the bedroom to reduce exposure to any sunlight.
- Go to bed as soon as possible after the night shift (within 1-2 hours). This allows time to achieve the most sleep and reduces exposure to daytime light, which inhibits sleep. While it can be tempting to run errands or work-out after a night shift ends, postponing daytime sleep forces sleep to occur at an even more inappropriate circadian phase and results in exposure to more daytime light.
- Exposure to bright light during the night shift is as important as shifting the sleep-dark period to the day time. Bright light during night shifts should be blue light; longer exposure (up to 6 hours at the beginning of the shift) is best, although 3 hours duration or even 20 minutes per hour for the first 6 hours have also shown beneficial effects. The spectrum and intensity of light have been studied, with no firm consensus as to what is best.
- In the days leading up to night shifts, shift the sleep schedule later in order to wake-up at least 3-4 hours after the end of the night shift. For example, if the overnight shift is 6PM – 6AM, then the 8-hour sleep schedule should be shifted to 2AM – 10AM or later. This makes the transition to day sleep easier with the addition of early daytime darkness and wearing sunglasses during the commute home.
- Melatonin appears to only have beneficial effects in select few people taking it in the morning after night shifts. This is probably because the problem is not usually falling asleep, but rather staying asleep after night shifts. It could also be due to daytime light exposure or lack of night shift light exposure, both of which will counteract the effects of the melatonin. If taking melatonin, know that a 0.5 or 1 mg dose is sufficient for most adults, and that the doses found in many drug stores or pharmacies (up to 10 mg tablets!) exceed what the body needs.
- It takes approximately 3-5 days to adjust to night shifts. This means that shift workers scheduled for 3 or fewer night shifts in a row should not use phase-shifting (shifting their clock). Instead, they should rely on other tools such as short rest periods (i.e., naps) and caffeine consumption to ensure wakefulness during night shifts.
- Permanent night shift workers should try to maintain a daytime sleep and nighttime working schedule. Many permanent night shift workers continuously rotate between sleeping during the day during work shifts and sleeping at night during days off, which can make it difficult to fully adapt to night shifts. Ideally, permanent night shift workers should try to delay their sleep cycle enough that they are waking up 3-4 hours (or longer) after they would be going to sleep after a night shift (i.e., going to bed at 3 or 4 AM and sleeping for 8 hours).
Marie K. Holowaychuk, DVM, DACVECC is a small animal emergency and critical care specialist and certified yoga and meditation teacher who also has an invested interest in the health and well-being of veterinary professionals. She organizes Veterinary Wellness Workshops & Retreats for veterinarians, technicians, and other veterinary care providers. To sign up for newsletters containing information regarding these events and veterinary wellness topics, please click here. More information can be found at www.criticalcarevet.ca/wellness.