What Happens When Women Do Night Shifts? Expert Explains Health Side Effects

A new study from the University of Manchester found that women working night shifts are more likely to have moderate or severe asthma. The study did not find the same link in men. The research, published on 16 June 2025 inERJ Open Research by the University of Manchester, looked at data from over 270,000 people.

The study was done by Dr Robert Maidstone and his team at the University of Manchester and colleagues. He said, “Asthma disproportionately affects women. Women generally have more severe asthma, and a higher rate of hospitalisation and death from asthma compared to men.”

To understand this better, we spoke to Dr Saurish Hegde, MD, Community Medicine, Public Health Specialist, author, and Founder of Food Chain Campaign. From rising stress levels to an increased risk of chronic conditions, the effects are far more serious than they may seem.

How Working On Night Shifts Affects Women’s Health

1. Understanding Biological Clock

Dr Saurish Hegde shared, “Our human body is based on a biological clock, which is regulated by our hormones. Cortisol and melatonin are the main sleep hormones, which are produced by the pineal gland.” Night shifts interfere with this clock. Cortisol and melatonin are vital sleep hormones produced by the pineal gland. Cortisol wakes us up during daylight, while melatonin, the sleep hormone, helps us fall asleep when it gets dark. When lighting is out of sync, so is the body’s rhythm.

2. Light, Cortisol, And Melatonin Disruption

Sleep-wake cycles rely on sunlight exposure. When the sun hits our skin, cortisol levels rise, energising us for daily activities. Dr Saurish Hegde explains, “Sleep-wake cycle is dependent on the sunlight exposure. When sunlight hits the body, the cortisol levels rise, and it activates the body to do daily activities. On the other hand, melatonin is the sleep hormone, when darkness prevails, the hormone will promote sleepiness.”

This stimulates cortisol, disrupts melatonin production, and disturbs the natural rhythm of the body.

3. The Domino Effect: Health Consequences

Shift work can elevate cortisol levels over time and stress the system. Studies highlight that night-shift workers often have higher cortisol and reduced melatonin levels. Dr Saurish Hegde shared, “Women work through the nights, and it disturbs the sleep-wake cycle. This will lead to an excess of cortisol levels in the body, which can cause a lot of stress, which can lead to morbidities over the longer run like asthma, hypertension, and diabetes.”

Don't miss:4 Health Benefits Of Doing Anulom Vilom For 5 Minutes In The Morning

4. Stress And Cortisol Spikes

Women face an extra hormonal load from their menstrual cycles. Adding night-shift stress and cortisol spikes exacerbates risk. Specifically, “when women do night shifts, the cortisol levels increase, adding stress and increasing the chances of asthma or breathing disorders over the long run”, says Dr Saurish Hegde.

Women who work nights can see disrupted reproductive hormones, too, leading to irregular cycles, fertility issues, early menopause, and other reproductive effects.

Don't miss:Top 5 Signs of Ageing in Your 30s, According to Dermatologist

Health Risks For Women Working On Night Shifts

1. Cancer Risk

Light exposure at night suppresses melatonin, a natural anti-cancer hormone. Shift work is classified by the International Agency for Research on Cancer (IARC) under the World Health Organisation (WHO) as a probable carcinogen. Women working night shifts have nearly a 50% increased risk of breast cancer, as per a2025 study.

2. Metabolic And Cardiovascular Problems

Disrupted circadian rhythm is linked to higher diabetes risk, heart disease, and metabolic disorders.

3. Mental Health

National Institutes of Health (NIH) states, “Shift work increased the total risk of negative mental health outcomes (such as depression and anxiety) by 28% among 28,431 workers, according to a study by Torquati et al.” Poor sleep quality and misaligned rhythms can lead to anxiety, depression, cognitive decline and mood disorders.

Night shifts challenge a woman’s natural hormone balance. But with careful lifestyle adjustments and protective habits, many of these risks can be managed.

For more such stories, stay tuned to HerZindagi.

Image credit: Freepik