Everyone falls ill occasionally, whether it's a simple cough, cold or flu, but some people appear to suffer from poor health more frequently than others.

Infectious diseases triggered by bacteria and viruses, alongside non-infectious conditions connected to lifestyle, environmental factors and genetics, all contribute to sickness. A UK-based doctor has shared five major factors behind why people become unwell.

GP Dr Sami is a qualified healthcare professional who posts educational health content, expert guidance and advice on TikTok. In a recent video on the social media platform, he outlined five causes of consistently feeling under the weather.

He also explained what steps you can take to address them. The doctor explained: "Do you keep getting ill more than the average person should do?

"It's not just bad luck. These are the top five reasons why people regularly get ill."

Dr Sami stated that research has demonstrated that getting fewer than seven hours of sleep can triple your risk of catching colds and other viral infections, noting that your immune system "needs sleep just as much as you do." The Mayo Clinic reports that people who fail to achieve quality or adequate sleep are more susceptible to illness after virus exposure, such as common cold viruses, and lack of sleep can impact recovery speed when sickness strikes.

The GP proceeded to his second point, saying: "Chronic stress keeps cortisol levels high and cortisol suppresses white blood cells, which are the cells that fight off infection." Cortisol is a hormone released during stressful periods, and prolonged stress weakens white blood cells, making you more susceptible to viruses such as the common cold and cold sores, according to Cleveland Clinic.

Many people try to maintain a healthy diet by eating nutritious food and drinks but the UK doctor revealed that most of us fail to consume our five daily portions of fruit and vegetables, which he described as a "problem" since we require nutrients like vitamin C and zinc to strengthen our immune system. Dr Sami continued: "We also need to get outside more and get some sunshine because vitamin D plays a really key role in how strong our immune system is."

It's widely recognised that certain environments increase your likelihood of falling ill, particularly if you're employed in healthcare, education, childcare or regularly commute by bus or train, as highlighted by the medical expert. He clarified that you will be "exposed to more bugs than the average person."

The doctor suggests consistently washing your hands and sanitising frequently-touched surfaces, such as door handles and handrails.

Dr Sami observed that underlying health conditions, including anaemia, thyroid disorders and digestive or liver complications can leave you feeling unwell. He recommends consulting with your GP if you believe you may have any of these conditions.