Exercise and health: An interview with Professor Karim Khan
PROFESSOR KARIM KHAN - THOUGHT LEADERS SERIES... Insight from the world's leading experts
Your recent work highlighted that regular exercise and/or participation in sports can have benefits both for physical and mental health. Please could outline what particular benefits may be gained?
I’ll quote from the ‘7 investments’ document (see below) as I don’t believe we need to reinvent the wheel to argue for the benefits of exercise. I am very keen to move to the issue of ‘how can we help people exercise’. But for the record:
“Physical inactivity is related (directly and indirectly) to the other leading risk factors for NCDs such as high blood pressure, high cholesterol and high glucose levels; and, to the recent striking increases in childhood and adult obesity, not only in developed countries but also in many developing countries.
Substantial scientific evidence supports the importance of physical inactivity as a risk factor for NCD independent of poor diet, smoking and alcohol misuse.
Physical activity has comprehensive health benefits across the lifespan: It promotes healthy growth and development in children and young people, helps to prevent unhealthy mid-life weight gain, and is important for healthy ageing, improving and maintaining quality of life and independence in older adults.” (Source: British Journal of Sports Medicine - BMJ)
The recent press release regarding your work reported that “regular” participation in sports and/or exercise has clear benefits for physical and mental health. Please could you define “regular”, i.e. how much exercise should we be doing to gain these benefits?
This is easy to answer in two ways. First, the ‘guidelines’ are that each of us should accumulate 150 minutes of moderate to vigorous physical activity per week. That’s 22 minutes a day of walking! That advice is for ‘public health’ - it will make a population healthier compared with being sedentary.
The second answer is that as an individual, it makes really good sense to accumulate 60 minutes of moderate to vigorous physical activity daily. This is still just walking - and it can be done in 10-15 minute bouts! So it still leaves 23 hours a day for sitting, lying and sleeping!
Why 60 minutes? Because there is a ‘dose-response’ curve - and so by being ‘selfish’ and taking twice the public health dose of physical activity, I reduce my risk of death, dementia, key cancers, coronary artery disease a further 20%. It’s not as good ‘value for money’ as the first 30 minutes but I am going to sneak that extra dose while no-one is looking!
After 60 minute the benefits largely level off to a point. Superior fitness is associated with superior health but do at least 30 minutes daily; if you are scared of cancer, dementia, a low quality of life and dependency in later life - accumulate 60 minutes and do it now!
You have been quoted as saying “low fitness is a better predictor of mortality than obesity or diabetes”. How can you back up this statement?
Professor Steven Blair has clearly shown that for a nation - say the US - the total burden of disease that is killing folks is mostly generated by low fitness. Low fitness means the bottom 20% of folks in a graded walking test - essentially a measure of aerobic fitness.
Professor Blair’s results, from the 20-year Aerobics Centre Longitudinal Study (ACLS), show that those folks in the bottom 20% of fitness as 55- year olds, will contribute to almost 20% of those who die in the next 20 years.
Taken together those who smoke contribute less than 10% of the deaths in the next 20 years and similarly those how are obese, or diabetic, each contribute less than 5% of the deaths. This is an argument for policy makers to pay a lot more attention to low fitness than they do currently. Walking for 22 minutes daily will keep you out of the bottom 20% for fitness.
If you consider the term ‘smokadiabesity’ - a terrible condition of smoking, diabetes, and obesity combined - the interesting thing is that low fitness actually kills more Americans than smokadiabesity! This comes from the same data from Professor Steven N Blair I referred to above.
You believe that health professionals need to pay more attention to their patients’ fitness. What in particular do you think this should involve? Are there any specific tests that you think should be routine?
Physicians should be role models - no physician should do less than the guideline level of physical activity. Note that overall physicians are more active than the ‘average’ person. Remember that educational level associates very strongly with adopting physical activity behaviour. This has been shown repeatedly. Physiotherapists often do a great job of being physically active.
In the clinic, physicians should include the ‘exercise vital sign’ in every consultation. Alongside measuring blood pressure, physicians (office staff in fact!) should just ask each patient two questions. First, how many days a week do you undertake moderate physical activity? Walking is fine! Second, for how many minutes, on average, do you undertake such activity on those days?
So if the person is active on three days a week for 20 minutes the weekly total is 60 minutes. Remember that the guideline benchmark is 150 minutes so then the clinician can alert the patient to taking action to reach the benchmark.
This physical activity counselling can be addressed in the last 30 seconds of the office visit - it does not have to distract from the purpose of the visit. Referral is fine - the physician’s role is to emphasize the importance of the issue by measuring it at every visit and to make the diagnosis of physical inactivity were it exists.
In what ways do you think health professionals could help patients that were deemed unfit?
Health professionals should counsel if they feel skilled and the time is right or they should refer to community resources or other professionals as they would refer for any other medical condition.
Physicians - health care providers - are one part of a 7-component program that will make our nations physically active. The list of 7, very practical steps can be found at this link http://bjsm.bmj.com/content/46/10/709.full and easily by googling ‘7 investment for physical activity’.
Physical activity advocates the need to align under the ‘7 investments’ flag or the very similar US Physical Activity Plan - the operational plans that flow from the National Guidelines in many nations. The great threat to getting physical activity on the agenda is fighting amongst ourselves as to whether ‘school sport’ or ‘active transport’ or ‘health professional counselling’ should be the priority. That is crazy. Each advocate should remind policy makers that (i) the evidence is incontrovertible, and (ii) the next steps are clear - see the 7 investments document OR the US Physical Activity Plan. Choose the part you want to fund/implement and get to it. The only barrier is lack of political will.
You have been quoted by David Holmes, as saying that sports and exercise medicine was viewed as a “pseudo-speciality” for much of the 1990s and early 2000s. How has this progressed and do you feel your work has contributed to changing this view in any way?
In Australia (which was my reference for that comment) there was resistance to ‘sports and exercise medicine’ having specialty status as one would expect with any innovation. The specialty already existed in many countries in Europe. This is not the place to outline the rationale for the specialty but remember that ‘organ specialties’ have surgical and internal medicine parallels. Cardiologists and cardiothoracic surgeons; neurologists and neurosurgeons. There are no internal medicine counterparts to orthopaedic surgeons.
In addition, exercise medicine crosses all health disciplines - exercise improves health universally. But, specialists in neurology, respirology, obesity, etc. are not trained in exercise prescription. It is no brainer that this requires specialists as well as GPs who have a strong training in the field. A textbook like Brukner’s Clinical Sports Medicine (20 years strong, now in 4th edition) with 68 chapters and 1268 pages underscores a curriculum for a specialist sport and exercise medicine field.
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