What a 12-hour work day can do to your metabolic, mental and reproductive health

When India brought in the new labour codes that came into force in November 2025, there was a structural change in the manner in which work hours could be organised. Even though the ceiling on a maximum of 48 hours a week still stands, employers can now choose to bring in longer work days over shorter durations: such as a four-day regime with a stretch of 10-12 hours every day.

In theory, the approach is progressive for employees, offering fewer days of commuting, longer weekends, and flexibility. However, an increase in hours of work can have a wide range of hidden health and psychological consequences.

Circadian rhythm disruption

Extended working hours, especially in the late evening, disrupts the body’s natural circadian rhythm, which refers to the sleep, metabolic, and hormone secretory patterns. Recent scientific reviews have established that long periods of circadian rhythmic misalignment are correlated with cortisol level changes, delayed melatonin secretion, and decreased insulin sensitivity. Consequently, glucose levels may become unregulated, and the metabolism process, inefficient.

In its turn, the World Health Organization has already registered, as probable, the risk of getting ill from the circadian rhythm disruption due to irregular work hours.

Metabolic health

Prolonged sitting and improper timings of meals are the main challenges faced while working for 12 hours a day. Previous studies have indicated that prolonged sitting that extends over 8 to 10 hours is known to greatly reduce the uptake of glucose by the muscles, even for people with an adequate amount of physical activity. A 2020 study indicated the ill effects caused by improper meal timings on insulin resistance in the human body; other studies too, have pointed to this.

In compressed work models, meals are delayed or missed; eating is often late at night, which adds to weight gain, irregularities in blood sugar regulation and the risk of metabolic disorders. This then sets the stage over time for the already increasing rates of both type 2 diabetes and heart disease in the working population of India.

Thyroid, adrenal health

Although a compressed working schedule does not have a direct causal effect on thyroid disorders, both stress and lack of sleep have an indirect impact on the way the body metabolises thyroid hormones. It is postulated that stress affects the bioconversion process, blocking the conversion of thyroid hormones from inactive to active, leading to fatigue and mental sluggishness, particularly for those whose hormonal balance is easily upset.

Furthermore, a state of persistent stress can affect cortisol levels. This can lead to manifestations of adrenal strain, defined by symptoms of persistent exhaustion, low capacity for handling stress, and sleep problems. Adrenal strain is further pronounced among persons suffering from fatigue, autoimmune proneness, and/or those exposed to high job strain.

Mental health and burnout

Increased hours can have a damaging effect on productivity. In occupational psychology research, results show that after 9-10 hours, attention, memory, and emotional control are significantly reduced.

Decision fatigue becomes the major concern when it comes to longer shifts, such as those seen within the healthcare, finance, technology, and/or management industries. With emotional exhaustion, irritability may actually increase rather than lessen.

Early warning signs such as disturbances in sleeping patterns, emotional flatness, decreased motivation, and stimulant use are observable before the onset of clinical burnout, emphasising the need for a preventive over a curative approach.

Reproductive health

From the reproductive health viewpoint, the implications are most important among women in their late 20s to 40s. Sleep deprivation or problems with the circadian rhythm cause altered functioning in the hypothalamic-pituitary-ovarian axis, affecting ovulation, regularity of the menstrual cycle, and hormone secretion.

There is existing evidence that relates the consequence of chronic stress and low sleep quality to the exacerbation of diseases such as PCOS and endometriosis, which involve the major contribution of insulin resistance and inflammation, respectively. Stress-induced hypothalamic amenorrhea, a suppression of the menstrual cycle, is a consequence seen in women under high physical and emotional strain.

For couples seeking to conceive a child, levels of cortisol, irregular habits, and a lack of emotional intimacy have been identified to adversely affect fertility levels. Stress also affects sperm quality, thus reiterating the fact that fertility is a non-gender issue.

The way forward

Flexibility, on its own, is not enough. The introduction of safety measures, including restrictions on long hours, mandatory restoration periods, and a break during meal times, are essential. Hybrid models, ergonomics at the workplace and mental health support offered by employers can also play a role in lessening the impacts of long hours.

The issue with the Indian experiment with the compressed workweek is not about the legality of the practice but about the biological and psychological feasibility of such an idea. The risk of such an innovation with employees is that their flexibility may come with costs to overall health and well-being.

(Dr. Narendra B.S. is lead consultant, endocrinology & diabetology, Aster Whitefield Hospital, Bengaluru, narendra.bs@asterhospital.in; S. Giriprasad is a psychologist at Aster Whitefield Hospital, Bengaluru; giriprasad.work@gmail.com; Dr. Pallavi Chennamaraju is a fertility specialist at Nova IVF Fertility, Chennai, pallavi.chennamaraju@novaivffertility.com)

Published – February 01, 2026 02:46 pm IST