Australian study shows shift workers prioritize sleep over diet and exercise

By Hugo Francisco de SouzaReviewed by Susha Cheriyedath, M.Sc.Dec 4 2023

In a recent study published in the Journal of Activity, Sedentary and Sleep Behaviors, researchers investigated the prioritization of health behaviors amongst Australians. They used phone and online surveys to evaluate sleep, physical activity, and diet prioritization patterns among 1,684 Australian adults between the ages of 18 and 72. Their findings revealed that 49% of all Australian adults prioritize diet, but the shiftwork-only subset of participants prioritized sleep. Their analyses found associations between shiftwork experience (number of years) and sleep prioritization, suggesting that occupation plays a fundamental role in health behavior resource allocation. Hence, this study highlights how occupation and capability modify the prioritization between these 'three pillars of health.'

Study: Exploring the prioritisation of sleep, diet, and physical activity as pillars of health: correlates and associations with health behaviours in Australian adults. ​​​​​​​Illustration created with the assistance of DALL·E 3

Modifiable health behaviors and the dangers of chronic diseases

Chronic or lifelong diseases are (predominantly) non-communicable diseases such as type 2 diabetes (T2D), cardiovascular diseases (CVDs), and cancers, which collectively form the leading mortality cause globally. Research has identified that the best deterrent against these conditions is modifiable health behaviors, of which diet, sleep, and physical activity are the most important.

These three behaviors play such a profound role in preventing chronic diseases that scientists and clinicians have christened diet, exercise, and sleep patterns as the "Three Pillars of Health." These pillars have been hypothesized to be especially important for populations and occupations (such as shift workers) with high poor health risks. Shift workers have work schedules significantly different from conventional work hours, resulting in severe disruptions to circadian rhythms. These disruptions, in turn, are associated with poor and inadequate sleep and may result in altered food intake patterns.

"Inadequate sleep, insufficient physical activity, and an unhealthy diet are each independently associated with an increased risk of chronic disease and therefore independently contribute to a large burden on the healthcare system."

Despite a growing body of literature on the benefits of good health behaviors, studies aimed at understanding behavior prioritization in adults remain lacking, with no studies having yet investigated the topic from the Australian context. The association between prioritization and behavioral outcomes similarly remains unexplored.

About the study

In the present study, researchers aimed to elucidate the health behavior differences between general and shift worker cohorts and how these prioritisations translate to actual behavioral outcomes. They further investigate the sociodemographic factors that influence both behavioral prioritization and outcomes.

Data for this study was derived from two cross-sectional studies, both of which were guided by the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines. The first study included 1,151 Australian adults aged 18-65 years (54% female). This 'general' cohort represented all sociodemographic and employment classes (including unemployed and retired) and was conducted using a phone interview.

The second study included 533 Australians between the ages of 18 and 72, all of whom were currently employed as shift workers. Data generation herein comprised an online questionnaire survey that measured respondents' prioritization of sleep, diet, and physical activity and how these prioritisations influenced respondents' actions. Outcomes were measured using previously established metrics of sleep duration, physical activity intensity and frequency, and dietary behaviors (healthy or unhealthy).

Statistical analysis consisted of within-cohort multinomial logistic regressions to evaluate the associations between participants' priority list and their behavioral correlates.

Study findings

The present study revealed that Australians generally prioritize diet as their most important health behavior (49.3%), followed by sleep (29.2%) and physical activity (21.5%). Surprisingly, 62.3% of respondents presented body mass indexes (BMIs) in the overweight-obese category (BMI  > 25kgm²). Encouragingly, 69.8% of respondents did not present sleep disorder symptoms.

Substantial changes in health behavior were noted when moving from the general to the shift working cohort, with sleep prioritized by an overwhelming 67.7% of respondents. In comparison, only 20.2% and 12.0% of respondents considered sleep and physical activity, respectively, as priorities. Demographic analyses revealed that sleep received the highest priority amongst shift workers irrespective of the specific shift worker occupation – Participants involved in retail trade, information media, and telecommunications regarded sleep as their most important health behavior without exception.

Unfortunately, behavior prioritization did not translate adequately to health outcomes – 54.0% of respondents failed to meet the minimum recommended sleep frequency and duration guidelines. Interestingly, the duration of shiftwork experience was found to be positively associated with sleep prioritization, with participants presenting 16 or more years of experience being almost 100% likely to consider sleep their first priority despite most not receiving adequate sleep.

Conclusions

The present study explores the general and shift workers' prioritization of health behaviors in Australia and how these priorities correspond to behavioral actions and health outcomes within the Australian context. Findings reveal that while most Australians consider diet their first priority, shift workers instead feel that sleep is the most important actionable health behavior among the Three Pillars of Health.

Unfortunately, this study revealed that prioritization does not translate to positive health outcomes – most of the general cohort that reported diet prioritization were found to be overweight or obese. Most of the shift worker respondents who reported sleep were found to be sleep-deprived.

Notably, both general and shift worker cohorts paid the least attention to physical activity, which might explain the high BMI of the former cohort and be due to insufficient time in the latter.

"These findings suggest that behavior prioritization is only part of the story of behavior change, and future research should focus on comprehensive approaches to behavior change promotion that target the barriers to specific behaviors."