How late night shift work is rewriting our genetic future and what we can do about it

In the relentless pursuit of a 24-hour economy, a quiet biological crisis is unfolding. Traditional nine-to-five jobs are now a mere pipe dream for millions. While the world sleeps, a vast workforce is labouring away to keep the wheels of industry, healthcare, and technology turning, along with gig workers who deliver food and necessities well past the midnight hour. However, these late night shifts, while necessary for livelihoods, are also a physiological gamble that affects stress levels, lifestyle habits, and potentially, the very blueprint of future generations to come.

The circadian conflict

Human biology is governed by the circadian rhythm which is an internal master clock that dictates everything from hormone production to core body temperature. When we work night shifts, we aren’t just fighting sleepiness; we are fighting hundreds of millions of years of evolution which are coded into our body that are forced to change all of a sudden.

Constantly living life against the schedule of daylight and night time can trigger a sustained release of cortisol, the body’s primary stress hormone. When cortisol remains elevated, the body stays in a perpetual state of high alert. This chronic stress not only makes one irritable or tired, but also erodes the cardiovascular system and immune response. Such people miss out on vitamin D, which is very important for the production of calcium in the body; compromising it eventually weakens our bones.

Search for stimulants

For many, the mental fatigue of ‘graveyard shifts’ leads to a dangerous coping mechanism: the search for a chemical reset, which forces the body to adjust to an inverted sleep schedule where processes in the body – including production of melatonin, cortisol and adrenaline – have to be intentionally adjusted.

To bridge the gap between exhaustion and performance, many shift workers turn to stimulants, usually smoking. Slowly. this turns into an addiction during ritualised breaks that usually provide momentary perceived relief in a high-pressure environment. However, nicotine constricts blood vessels and spikes blood pressure, compounding the damage already being done by lack of restorative sleep.

Sleep deprivation is not merely a feeling of tiredness. It is a complete systemic failure. During deep sleep, the brain flushes out toxins and the body repairs cellular damage. When this process is truncated or is of poor quality due to daylight and noise outside, the body remains in a state of inflammation. This triad of night shifts, nicotine, and insomnia creates a toxic physiological environment that the body was never designed to endure.

The next generation effect

Perhaps the most universal fallout of this lifestyle is that it does not end with the individual. We are learning now that our environment and lifestyle choices can leave genetic changes, which mark our DNA.

Genetics and family history are the foundation of a child’s health. If both parents are operating in a state of physiological depletion, there is a significant risk that the next generation will be born with a predisposition to metabolic disorders, which can result in a higher baseline for obesity and Type 2 diabetes. There is reduced resilience due to a weakened nervous system, which makes them less capable of handling stressors. Inherited tendencies could include cardiovascular vulnerability, hypertension and heart disease.

If we continue to normalise a lifestyle that ignores biological boundaries, we risk raising a generation that lacks the physical and mental vigour of their ancestors.

A path to reclamation

Breaking this cycle requires more than just occasional salads or gym memberships; it requires a radical commitment to preventative healthcare. A healthy lifestyle is the first line of defence, but in an age of hidden stressors, we cannot rely only on how we feel. This is where the importance of regular medical check-ups becomes important for everyone in today’s times.

A comprehensive health screening acts as a mirror, reflecting the internal realities that are not visible otherwise. It identifies silent killers including high cholesterol, early-stage hypertension, and fatty liver disease long before they manifest as a crisis in our lives.

Among a battery of modern medical tests, one stands out as a critical diagnostic tool – the Treadmill Test (TMT) or cardiac stress test. Unlike a resting ECG, which only captures a snapshot of the heart at ease, the TMT pushes the heart to reveal its true condition under exertion. A Treadmill Test is important as it detects ischemia, which is a condition of reduced blood flow to the heart that might not be visible while sitting still. It also helps in assessing our fitness levels as it provides a concrete metric of cardiovascular endurance, which is often severely compromised by smoking and late shift work. It gives us that early warning, to detect arrhythmias or blood pressure spikes that occur only during physical stress, allowing for intervention years before a potential heart attack.

By monitoring heart rate, rhythm, and blood pressure while the intensity of exercise increases, the TMT provides a dynamic stress test for the system that shift work and smoking undermine.

What you should know

The world will continue to offer midnight shift jobs across sectors, but our attitude towards them has to change for the better. If your job demands that you go against the grain of nature, then you have to be doubly careful about your health and not treat your body like a machine that runs on auto mode forever.

We owe our health not only to ourselves, but also to the generations that will follow us. Sleep as much as you can, ditch that pack of nicotine, and choose clarity of health that comes with regular medical checkups to identify what we are doing wrong early on, and strengthen what we are doing right.

Changing jobs or sectors is not possible for a vast majority of people. But finding ways to move from stress towards good health, can be.

(Dr. Arunkumar Ullegaddi is consultant cardiologist, Narayana Health City, Bengaluru. arun_i_u@yahoo.co.in)

Published – March 01, 2026 06:19 pm IST