Several jobs require working night shifts, such as security guards, hospital staff, hotel receptionists, industrial operators, among others. This implies that people must adapt by changing their sleep schedules, meal times, exercise routines and other daily habits.

But do we know to what extent night shifts affect our cardiovascular health?

The main impact of night shifts on our body is known as chronodisruption. What does it consist of? Chronodisruption refers to the alteration of light/dark cycles, fasting/eating cycles, or sleep/wake cycles. Chronodisruption implies changes in the secretion of a large number of hormones in the body, many of them related to the cardiovascular system, and may lead to changes in blood pressure, heart rate, levels of epinephrine and norepinephrine, platelet aggregation, or the response of the immune system.

And what does scientific evidence say about night shifts and chronodisruption?

A study that began in 1996 in southern France followed 3,138 workers aged 32 to 62 from different sectors over a period of 20 years, with the aim of assessing whether their work could increase their risk of mortality. Several factors were observed to increase mortality, such as exposure to high noise levels for more than 6 years, working while carrying heavy loads for at least 8 years, and especially working night shifts, which increased mortality risk by up to 1.5 times. Even recent meta-analyses, which represent one of the highest levels of scientific evidence, also highlight an increased risk of cardiovascular disease and even cancer associated with night shifts.

With all this scientific evidence behind it and a more than proven risk, researchers have tried to study the causes and modifiable factors, and to what extent these could benefit workers who are at a significantly elevated risk.

Factors that may affect our cardiovascular health

The first factor studied is chronotype. Several studies have not reached a clear conclusion on the importance of chronotype adaptation in relation to cardiovascular risk associated with different work shifts. Some studies observe an increased incidence of type 2 diabetes, while others find no association with cardiovascular risk factors.

The second factor is genetics. Various studies have investigated which genes may be truly important in determining who is at significantly higher risk and who is not. The first study, conducted in 242,754 participants, observed that the genetic burden studied significantly increased cardiovascular risk, especially in women, with the risk almost tripling when compared to women with low genetic risk. For genetic risk associated with work schedules, experts have used genes related to circadian rhythms and chronotype, such as MTNR1B, PER2, NPAS2, CLOCK or NAT2, among others.

Other factors studied to better manage cardiovascular risk associated with night shifts include taking naps during night shifts and reorganising meal times during these shifts.

Regarding the former, several studies highlight that taking a 3-hour nap can reduce cardiovascular risk due to improvements in blood pressure compared to workers who do not take naps. However, realistically, not everyone can take a 3-hour nap during a night shift, but it is worth noting that it is an effective measure. On the other hand, we have the reorganisation of meal times in relation to night shifts. According to scientific evidence, no significant changes are observed in markers such as blood lipids or blood glucose levels; however, significant differences are found in body weight, one of the most important factors in cardiovascular risk.

A change in our habits

In conclusion, the health risks associated with night shifts are real and should not be underestimated. There are also a number of measures we can take to mitigate these risks, such as understanding our genetic risk, controlling meal timings, taking naps during shifts, or seeking alternative work schedules.

References

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