Shift work and your internal biological clock

Shift work, night duties and irregular sleeping hours can affect the functioning of the entire body. The human body has an internal biological clock responsible for synchronizing many physiological processes with the natural day-night cycle.

The circadian rhythm regulates, among other things, sleep, body temperature, hormone secretion, appetite, digestion, recovery and immune system function. When the hours of activity and rest change frequently, the body can struggle to maintain its natural balance.

An irregular lifestyle can also affect the gut microbiota. The bacteria living in the digestive tract also function according to a circadian rhythm, responding to sleep times, meal times and physical activity.

What is the human circadian rhythm?

The circadian rhythm is a natural cycle of changes in the body that repeats approximately every 24 hours. Its operation is synchronized primarily by light and darkness.

The central biological clock is located in the brain, in the part of the hypothalamus called the suprachiasmatic nucleus. It receives information about light intensity and then sends signals to other areas of the body.

Individual organs also have their own biological clocks, including the intestines, liver, pancreas and adipose tissue.

Regular sleep, meal and activity times help maintain synchronization between these systems.

Why does shift work disrupt the biological clock?

The human body is naturally adapted to activity during the day and rest at night. Night work forces a reversal of this pattern, causing the internal biological clock to stop matching the actual hours of activity.

Light during nighttime hours can limit the natural secretion of melatonin, the hormone involved in regulating sleep. At the same time, sleep that takes place during the day is often shorter and more prone to interruption.

Rotating shift systems, where working hours change regularly, can be particularly demanding for the body.

In such cases, the body doesn't always have enough time to adapt to the new schedule.

How can night work affect wellbeing?

Improper synchronization of the circadian rhythm can manifest itself in many ways. The body's reaction is individual and may depend on the duration of shift work, its intensity and general health.

The most commonly experienced effects include:

• daytime sleepiness,
• difficulty falling asleep after a shift,
• frequent waking during sleep,
• a feeling of chronic fatigue,
• decreased concentration,
• irritability and worsened mood,
• reduced motivation for activity,
• appetite disturbances.

A single night shift usually doesn't have to mean serious consequences. Long-term functioning on an irregular schedule matters more.

Shift work and gut microbiota

The gut microbiota is a complex ecosystem of microorganisms living in the digestive tract. Gut bacteria support digestion, immune system function and the synthesis of certain vitamins and neurotransmitters.

Microbiota activity can change depending on the time of day. It is influenced, among other things, by meal times, sleep time and physical activity.

Night work can lead to a situation where meals are eaten at a time when the digestive system naturally works more slowly.

Long-term irregularity can affect the diversity of the microbiota and the functioning of the digestive tract.

How to take care of your body during shift work?

It's not always possible to give up night shifts, but the right habits can help limit their impact on wellbeing:

Consistency matters most. Even with a variable schedule, it's worth creating a few fixed elements of the day that act as a signal for the body.

Sleep after a night shift – how to improve its quality?

Daytime sleep is often shallower than nighttime rest. Your home may be brighter, louder and warmer, which makes recovery harder. It's worth taking care of conditions that support rest.

Before going to sleep, it's a good idea to limit the use of your phone, computer and other devices that emit blue light. Many people use eye masks or earplugs.

The bedroom should be as quiet, cool and well-ventilated as possible. If ambient noise makes it hard to fall asleep, white noise or other quieting methods can help.

It's also worth informing household members about your sleeping hours to reduce accidental waking.

What to eat during a night shift?

During nighttime hours, the pace of certain digestive processes may differ from during the day. For this reason, overly large or heavy meals may be less comfortably tolerated.

During a night shift, it's worth choosing simpler meals containing:

• vegetables,
• whole-grain products,
• sources of high-quality protein,
• healthy fats in moderate amounts,
• fiber-rich products,
• an adequate amount of water.

A good solution can be preparing meals before the shift starts. This helps reduce reaching for highly processed snacks available at work.

Signs that your body may need more support

It's worth paying attention to symptoms that may suggest that more support is needed:

Such symptoms don't necessarily point to a specific illness. However, they may signal that the body isn't recovering sufficiently.

Caffeine during a night shift – how to use it sensibly?

Coffee can help maintain concentration during night work, but the timing of its consumption matters a great deal for sleep quality after the shift.

It's best to avoid large amounts of caffeine in the final hours of work. This applies not only to coffee, but also to tea, energy drinks and other caffeine-containing products.

It's also worth remembering that caffeine doesn't replace sleep. It can only temporarily reduce the feeling of sleepiness, but it doesn't remove a sleep deficit or speed up recovery.

Physical activity and recovery after shift work

Regular movement can help maintain proper wellbeing, metabolism and a natural circadian rhythm.

This doesn't mean, however, that every person working nights should do intense training right after getting home. Intense physical activity right before sleep can make it harder to fall asleep.

Good solutions can include walks, gentle cycling, mobility exercises or moderate physical activities adjusted to your level of fatigue.

The type of activity should be matched to your fatigue level and individual tolerance.

How to support gut microbiota with an irregular lifestyle?

Taking care of gut microbiota doesn't have to mean introducing drastic changes. Consistent, everyday habits matter most.

It's worth remembering to:

• regularly eat vegetables and fruit,
• get an adequate amount of fiber,
• include fermented products in your diet, if well tolerated,
• limit highly processed food,
• avoid continuous snacking throughout the night,
• stay properly hydrated,
• take care of recovery and sleep,
• engage in regular physical activity.

In some cases, an appropriately chosen probiotic preparation can also be an element of daily microbiome support.

Probiotics during shift work – when are they worth considering?

Probiotics are live microorganisms which, when administered in an appropriate amount, can support the natural balance of gut microbiota.

They can be considered as a dietary supplement especially when an irregular lifestyle is combined with digestive complaints, lowered immunity or a general decline in wellbeing.

It should be remembered, however, that a probiotic doesn't replace a proper diet, sleep and recovery. It should be treated as one element of broader health care.

The specific bacterial strain, the number of microorganisms, how the product is stored and consistency of use also matter.

Narum Relax – support during periods of stress and an irregular lifestyle

Night work and a variable schedule can be associated with worsened rest quality, greater tension and difficulty winding down.

Narum Relax is a product combining the Narine Lactobacillus acidophilus bacterial strain with natural ingredients that support the nervous system: hop cone extract, lemon balm and L-theanine.

It can be a supplement to a varied diet for people exposed to stress, leading an intense lifestyle, or having difficulty resting regularly.

The best results come from combining conscious supplementation with a proper diet, sleep, hydration and physical activity.