TV doctor and NHS GP Dr Amir Khan has warned that shift work is "not natural" for human beings and increases the risk of health issues, particularly affecting the heart and blood pressure. Speaking on the podcast No Appointment Necessary with co-host Cherry Healy, he said the evidence of these risks is "very strong."
In the UK, around 3.5 to 3.6 million people (roughly 14% of the working population) do shift work most of the time, according to data cited by the Health and Safety Executive (HSE) and GOV.UK Guidance. An estimated 8.7 million people (about 26.7% of the UK workforce) usually worked in the evening or at night, based on Office for National Statistics (ONS) data.
What did Dr Amir Khan say about shift work?
During the episode, Dr Amir Khan explained that shift work is "not natural" for human beings, describing it as a man-made schedule forced upon people by society and industry rather than something our bodies are biologically designed for.
He said: "It isn't really; shift work is not natural. It's not natural for us human beings to do. It is a man-made forced upon thing that industry and science and industry and society has done to us. And there is no way around it."
He added: "Unfortunately, people who do shift work, there is no doubt in my mind, the evidence is very strong. They are increased risk of health issues with regards to their heart, blood pressure, all of these kind of things."
He went on to stress: "But it's easy for me to say that. If they need it to survive, then they need it to survive." Cherry Healy noted that a friend who works maternity night shifts gets paid 20% more for every shift, and at this point in her life "it's worth it." Dr Amir Khan replied: "That makes sense."
What health issues are shift workers at risk of?
According to health bodies such as the HSE and the NHS, the primary drivers of these risks are the disruption of the body's natural 24-hour biological clock (circadian rhythm) and chronic sleep deprivation. Irregular hours force the body to stay awake when biologically programmed to sleep, altering hormone production, core body temperature, and digestion, which often triggers chronic fatigue, insomnia, and a condition known as Shift Work Sleep Disorder.
In the short term, this disruption impacts the digestive and cognitive systems. Irregular eating schedules can lead to gastrointestinal problems like indigestion, ulcers, and bloating. Studies show that the risk of workplace accidents and errors is up to 30% higher on night shifts compared to daytime shifts.
Over the long term, research indicates that working night shifts alters how the body processes sugar, causing insulin resistance that raises the risk of obesity and Type 2 diabetes. Experts warn that high stress hormones and poor sleep quality contribute to higher rates of cardiovascular disease, high blood pressure, and mental health struggles like anxiety and depression. The World Health Organization classifies regular night shift work as a probable human carcinogen due to prolonged disruption of melatonin and cellular repair cycles.
What legal protections exist for night workers?
Under UK law, the Working Time Regulations mandate specific protections for regular night workers. Employers are legally required to offer free, confidential health assessments before night work begins and at regular intervals afterwards. The law also caps night shifts at an average of eight hours within any 24-hour period to help prevent severe exhaustion and protect worker well-being.
