Night shifts

What are night shifts?

Night shifts are work schedules where you work during the night, typically between 10 pm and 6 am. While often unavoidable, night shifts disrupt your biological clock and can have a significant impact on your health.

What is your biological clock?

Your biological clock, or circadian rhythm, is an internal cycle of roughly 24 hours that regulates the sleep-wake cycle and many other processes in your body. It keeps your body active when you need to be awake and helps it wind down when it is time to sleep.

Factors that influence your biological clock

• Environment: Light, sound, and temperature all play a major role in setting your rhythm.
• Lifestyle: Nutrition, movement, substance use, and stress all affect how well your biological clock functions.
• Nervous system: The activating branch is dominant during the day, while the restorative branch takes over during sleep.
• Hormones: Cortisol and adrenaline keep you alert, while melatonin prepares your body for sleep.

How do night shifts affect your health?

Working at night disrupts your biological clock, because you are active when your body needs rest. This can lead to:

• Sleep problems: Shorter and shallower sleep can cause chronic fatigue, sleep disorders, and anxiety around sleep.
• Metabolic disruption: Your metabolism becomes dysregulated, increasing the risk of overweight, type 2 diabetes, and cardiovascular disease.
• Mental health: Night shifts raise the risk of anxiety, depression, and a reduced sense of wellbeing.
• Weakened immunity: A disrupted sleep cycle makes your immune system less effective, leaving you more vulnerable to infections.
• Neurodegenerative conditions: Chronic disruption of your biological clock may increase the risk of Alzheimer's disease and dementia.

What can you do to counter the effects of night shifts?

While it is difficult to avoid the impact of night work entirely, there are several ways to better support your biological clock:

• Choose longer-term rosters: Work on the same schedule for at least two weeks, giving your body time to adapt.
• Keep to a routine: Try to carry out your daily routines as consistently as possible.
• Watch the sunrise and sunset: Seeing the sun set before your shift or rise after it can help anchor your biological clock.
• Make sure it is light when you need to be awake: Expose yourself to bright light during your night shift, but avoid strong light just before you sleep.
• Make sure it is dark when you need to sleep: Use blackout curtains or a sleep mask to make your room as dark as possible when you sleep.
• Avoid daylight when you need to sleep: Wear sunglasses if you need to go outside after your shift, to limit light exposure during your sleep period.
• Avoid caffeine and heavy meals: During your shift, try not to consume caffeine or large meals within 3–4 hours of going to sleep.
• Exercise at the right time: Exercise just before or during your night shift, and avoid it during your sleep period. This helps align your nervous system and body clock.