There have been a number of studies done on the importance of recovery days after working shifts. It’s logical¦.our bodies (and minds) can’t work at odd hours, long days, or rapidly rotating schedules, without being seriously impacted. Now, a few days before Christmas and a week before New Year’s, almost everyone is suffering from depleted energy. But as we continue to push ourselves to persevere, saying, “Just hold on and get through the holidays; it’ll be over soon”, we seek our ways to cope. Often we do this in a robotic-like fashion, not even consciously. We might drink a little too much hoping to calm ourselves down for sleep, pop pain-killers to reduce our aches and pains from all the running around, or skip dinner in favor of Doritos because we’re too tired to cook.
Sound familiar? These are the feelings, vegetative state, and survival tactics most shift workers face on a regular basis, not just around the holidays. If you work shifts, you know.
Back to recovery days….
In one study (Folkard et al, 1995), shift working nurses were provided with a handheld computer for 28 days so they could complete self-ratings, track cognitive-performance tasks, and maintain a sleep diary. Capabilities were worse on rest days following a night shift rather than a day shift. Cognitive abilities tended to be worse on the first rest day after working a night shift, compared with subsequent rest days. Alertness was lowest on the first rest day following a night shift. Social satisfaction was better when a workday was preceded by two, rather than one, rest day. Reaction time decreased over consecutive night shifts and tended to improve during rest days following night shifts.
A 2009 study (Kubo et al) looked at individual differences related to sleep recovery after working four consecutive night shifts. Study participants were all male, non-smokers, experiencing no sleep disorders, and none had worked shift work or travelled long distances (causing jet lag) in the three months prior to the study. Also leading up to the study, the participants avoided caffeine and alcohol, didn’t nap or deprive themselves of sleep, and kept a journal of their sleep/wake patterns. The ten day study (which included day-time and night time shifts and recovery periods) was carried out in a sleep lab for 24-hour days; participants’ sleep was monitored using a wrist actigraph and sleep monitoring software. During simulated working hours, the men were kept busy performing tests and tasks. Free time was also provided.
The researchers observed four patterns of sleep recovery after the simulated night shifts: rapid, slow, pseudo, and incomplete. Participants with rapid sleep recovery patterns almost immediately returned to baseline sleep efficiency. But, those with ˜slow’ and ˜incomplete sleep’ recovery patterns experienced a slow recovery or no recovery to baseline sleep on the third night after the night shift. And, participants exhibiting pseudo recovery patterns had poor sleep on the third recovery night despite having seemed to recover on the second night. The researchers found that sleep habits (e.g. consistency of bed times and wake times) before the experiment were significantly related to the recovery patterns.
Akerstedt et all (2000) found that for the average normal office week worker, the weekend’s“ two days of recovery, is normally sufficient. But for those who work long shifts in long sequences up to three days may be needed for normalization. Twelve hour shifts in 2-3 day sequences seemed not to cause accumulated fatigue. And, the study found that fatigue/sleepiness is often at its peak during the first day of recovery, not the last day of the working week, as some might have expected. The study suggests that one day of recovery never is sufficient, two recovery days usually are enough, and 3-4 days may be necessary after periods in which circadian rhythms are severely disturbed.
Fatigue can be physical and mental, acute and chronic. A 1998 study (Hennig et al), evaluated the size of changes and the time point of the changes in biological rhythms for night-shift workers in a cardiac unit for seven nights. Saliva samples were frequently taken and examined for the presence of the adrenal hormone cortisol (which has often been used in measuring the impacts of shift work since it tracks a pronounced circadian variation and has been demonstrated to be affected by night-work). In the study, by the fifth consecutive work night, it looked like circadian functioning was reversed for the group as a whole. But when individual results were evaluated in detail, six of the 24 participants showed no changes in circadian functions. And, these participants exhibited less sleep duration and less consistency in recovery sleep across the following days after night-work. The researchers point out that with respect to personality traits, a pattern associated with neuroticism can be found in people who don’ exhibit appropriate changes in cortisol rhythm. Possibly these people are more neurotic due to sleep deprivation?
It has been well documented by numerous studies that short-term sleep deprivation negatively affects performance. One study (Taylor and McFratter, 2003) tested the impact of sleep deprivation on time estimation, immediate recall, delayed recall, and digit span tasks (memory recall of digits called out by the tester). The study compared introverts and extroverts, neurotics and stable personalities. Extraverts performed worse than introverts on the time estimation, immediate recall, delayed recall, and finger tapping tasks. Significant interactions between extraverted and neurotic personalities existed in predicting performance on time estimation, immediate recall, delayed recall, and stroop tasks tests (testing ability to focus and present directed attention) were found “ neuroticism exaggerated the differences seen between extraverts and introverts.” The poorer accuracy of extraverts in comparison to introverts was more pronounced for those classified as neurotic vs. stable. But, neuroticism alone was not significantly related to the effects of sleep deprivation.
So if you’re extroverted and neurotic, be extra careful and make sure you take full advantage of your recovery days, so as to improve performance. But, introverts shouldn’t sit smugly on the sidelines. Studies show that introversion and depression may be linked. Since shift workers are at greater risk for anxiety and depression, every shift worker should be careful to maximize the benefits of recovery days.
During this holiday period, set two goals. First, build in some relaxation time for yourself. Second, if you believe in New Year’s resolutions, consider putting how you use recovery days at the top of your list. Discuss this with co-workers, family, and friends and make a plan. You’ll improve your physical health, emotional well-being, and productivity at work and at home.
Happy Holidays from Working Nights! Keep health and safety front of mind, all the time!
©2009 Circadian Age, Inc. ˜Working Nightsâ”
