Most medical students are not being taught about the benefits of exercise for patients, research in the British Journal of Sports Medicine suggests.
Researchers surveyed the UK's 31 medical schools and found instruction was "sparse or non-existent".
Only four taught undergraduates about the benefits of physical exercise in each year of their course.
In the new study, curriculum and medical studies leaders for each medical school were sent a survey which asked about the quantity and content of education about the promotion of physical activity.
They were also asked if the Chief Medical Officer's (CMO's) guidance on physical activity for all age groups, published in July last year, was part of the curriculum.
Five of the schools said they did not include any specific teaching on physical activity in their undergraduate courses. And only half included the current CMO guidance in their course.
The total amount of time spent on teaching physical activity was "minimal", the research suggests, averaging just four hours compared with an average of 109 hours for pharmacology (the effects and uses of drugs).
The researchers, led by Dr Richard Weiler, of University College London Hospitals, write in the journal: "A basic understanding of the benefits of physical activity, how to effectively promote it (with behaviour change techniques), and combat sedentary behaviour for different age groups underpin the ability of future doctors to manage modern non-communicable chronic diseases and follow clinical guidelines."
And they suggest there is a "major disconnect" between undergraduate medical education, clinical guidelines for long-term conditions and national policy.
They call for dedicated teaching time on physical activity for all medical students, as a matter of urgency.