The benefits of exercise on sleep for rotational shift workers.

Author: Sami Smith

Rotational shift work refers to shift work where the worker will work both day and night shifts, rotating through various start and finish times to cover a 24hr time frame. For example, a worker may start work at 0200-1200 on Monday, 0400-1400 Tuesday and 0700-1700 on Wednesday… and so on. This rostering structure means workers are unable to adjust their circadian rhythm to match their ever-changing sleep and wake schedules. Chronic sleep deficiencies and these consistent disruptions to circadian rhythm increases risk of chronic health conditions such as type 2 diabetes, hypertension, metabolic syndrome and cardiovascular diseases. Inconsistent sleep also impacts on cortisol regulation (one of our body’s main adrenal stress hormones), and cortisol dysregulation impacts sleep quality. Regular physical activity helps regulate both cortisol levels and sleep.

Specifically, exercise has been shown to improve quality and quantity of sleeping shift workers and those that experience insomnia. Both acute bouts of exercise and regular exercise participation improves total sleep time, efficiency, quality and slow wave sleep length. Slow wave sleep is the deep phase of sleep that is considered the most restorative phase of sleep.

The American College of Sports Medicine (ACSM) and the Australian Physical Activity guidelines recommends that every healthy adult should engage in moderate-intensity aerobic exercise for ≥30 minutes/day on ≥5 days/week for a total of ≥150 minutes/week.

What is moderate intensity aerobic exercise?

“You could speak in sentences, but definitely not sing”

OR

65-75% of your Maximum Heart Rate (MHR = 220-age)

Examples:

• Stair climbing
• Light jogging on road or treadmill (Minimum 4.0km/hr on treadmill)
• Stationary cycling
• Brisk walking (Minimum 4.0km/hr)
• Swimming laps
• Cycling on flat surfaces

When?

• For morning or day shift: Perform moderate intensity aerobic exercise a few hours before the main sleep time.
• For night shift: Perform moderate intensity aerobic exercise during the day, a few hours before an evening nap.

Other workplace interventions that have proven to be successful for improving sleep quality in shift workers include:

• Yoga and mindfulness practices
• Appropriate light exposure
• Melatonin supplementation
• Improvements to sleep hygiene

 

References:

1. Robbins, R., Underwood, P., Jackson, C. L., Jean-Louis, G., Madhavaram, S., Kuriakose, S., Vieira, D., & Buxton, O. M. (2021). A Systematic Review of Workplace-Based Employee Health Interventions and Their Impact on Sleep Duration Among Shift Workers. Workplace health & safety, 69(11), 525–539. https://doi.org/10.1177/21650799211020961
2. De Nys, L., Anderson, K., Ofosu, E. F., Ryde, G. C., Connelly, J., & Whittaker, A. C. (2022). The effects of physical activity on cortisol and sleep: A systematic review and meta-analysis. Psychoneuroendocrinology, 143, 105843. https://doi.org/10.1016/j.psyneuen.2022.105843
3. Okechukwu, C. E., Masala, D., D’Ettorre, G., & La Torre, G. (2022). Moderate-intensity aerobic exercise as an adjunct intervention to improve sleep quality among rotating shift nurses. La Clinica terapeutica, 173(2), 184–186. https://doi.org/10.7417/CT.2022.2414
4. Kredlow, M.A., Capozzoli, M.C., Hearon, B.A. et al.The effects of physical activity on sleep: a meta-analytic review. J Behav Med 38, 427–449 (2015). https://doi.org/10.1007/s10865-015-9617-6
5. Garber CE, Blissmer B, Deschenes MR, et al. American College of Sports Medicine position stand. Quantity and quality of exercise for developing and maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness in apparently healthy adults: guidance for prescribing exercise. Med Sci Sports Exerc. 2011; 43(7):1334-1359,
6. https://www.health.gov.au/topics/physical-activity-and-exercise/physical-activity-and-exercise-guidelines-for-all-australians
7. https://www.cdc.gov/physicalactivity/basics/measuring/heartrate.htm