The George Institute for Global Health at the University of Oxford measured the duration and intensity of physical activity levels over seven days and compared those participants with, and those without, chronic disease. They found that those with chronic disease, even those conditions that don't directly limit capacity for exercise, spent less time active.

Around 15 million people in England suffer from chronic disease [1]. Major types include cardiovascular disease (e.g. heart attacks and stroke), respiratory disease (e.g. asthma), and mental health conditions (e.g. depression). Chronic conditions are not passed from person to person, usually develop slowly, and are often characterised by the need for long-term management [2].

Healthy participants spent over an hour more on moderate activity (e.g. brisk walking and gardening), and 3 minutes (11%) more on vigorous activity (e.g. running and aerobics) a week than those with chronic disease. Researchers found that those with mental health disorders had the lowest moderate activity levels of all, spending 2.5 hours less per week than the average 11.8 hours of healthy peers.

"Chronic diseases are the emerging health burden of our time. We know that increasing physical activity is important both for the management of chronic diseases and also for preventing the development of new chronic diseases in an individual, so our findings give cause for concern," said Terry Dwyer, Professor of Epidemiology at The George Institute, University of Oxford, who led the research published in the International Journal of Epidemiology.

Some conditions, such as respiratory or mental health disorders, can limit peoples' capacity for exercise, for instance, owing to a reduced supply of oxygen or by lessening their motivation to engage in everyday activities.

However, not all chronic diseases (for instance some types of gastrointestinal problems and skin conditions) necessarily affect the capacity to be active. Some ill participants may have been habitually inactive, but the sick role may also have a part to play in this activity gap, whereby the very fact of being ill influences an individuals' tendency to exercise.

The World Health Organization recommends that adults are moderately active for at least 150 minutes per week to maintain a healthy lifestyle and help stem the onset of progressive, and potentially multiple, chronic disease diagnoses [3].

"The findings are particularly relevant to clinicians as they highlight the fact that doctors treating patients for any disease should be asking about how much physical activity they are taking. The disease they are suffering from might not be one that will kill them, but a reduction in physical activity consequent on having a disease will put them at risk of other serious chronic conditions such as diabetes, and certain cancers."

Professor Dwyer added, "Our findings offer a clear window of opportunity in which we can act to tackle this burden of disease to help people the world over."

[1] Department of Health information on chronic disease prevalence in the UK

[2] World Health Organization overview of non-communicable diseases and their risk factors

[3] World Health Organization recommended levels of physical activity for adults