Reassurance about the effects of exercise

We all know that regular exercise is “good for us” and the many health benefits of exercise were discussed in a previous blog on the 5th March 2015 – “More on the Benefits of Exercise”. There are certainly grounds to think that people with sickle cell stand to gain in many important ways from regular exercise, but there have always been those, doctors and patients, who took the view that exercising is too risky when you have sickle cell. Exercise might provoke a crisis or the acute chest syndrome, for example, and there are some theoretical grounds to support this point of view.

In many ways sickle cell can be thought of as an inflammatory condition.  Various chemicals, which can be measured in the blood and which are associated with the inflammatory response, are increased in concentration even in well patients with sickle cell disease. The levels of these chemicals increase further when patients become ill with a crisis. These blood markers include a wide range of different chemicals, some of whose names you may recognise from tests done when you go to hospital. They include: CRP (C-reactive protein), IL-6 (interleukin 6), TNF (tumour necrosis factor), fibrinogen, fibrin d-dimers and sVCAM (soluble vascular cell adhesion molecule) to name but a few. The WBC (white blood cell count) and platelet count are also generally raised in patients with sickle cell and behave in the same way as the other inflammatory markers, increasing further during a crisis.

Interestingly, these same markers are also increased in the blood of anyone who exercises. The less fit someone is the higher the baseline level of these so-called inflammatory markers and the more they go up during exercise. Regular aerobic training, when you get out of breath by running or cycling for example, results in an improvement in these markers and this may be the way that exercise helps to protect us against heart disease.

So, the argument goes, if these same chemicals are already increased in the blood of people with sickle cell, exercise will increase them further and so tend to exacerbate any ongoing inflammatory process such as a crisis, making the pain worse and causing the crisis to last for longer. If this were indeed true, it would mean that patients with sickle cell should be advised to avoid any strenuous physical activity and they would thereby be denied the all the health benefits of regular exercise.

A group of doctors from the Children’s Hospital in Chicago have tested this theory out on 60 young patients with sickle cell anaemia (average age of 15.1 years) and compared them with 30 young people without sickle cell. All of the subjects, normal and sickle cell, were maximally exercised on a static bicycle until they were too exhausted to continue and regular blood samples were collected during and after the exercise period. These test periods of maximal exertion lasted from 5-8 minutes at a time.

As you might expect, the sickle cell patients could not exercise at the same intensity or for the same length of time as the control subjects, however, they all managed to complete this fairly intense exercise regime without developing any sickle cell related complications. The baseline levels of all the inflammatory markers were raised in the sickle cell patients, even before they exercised  and, just as in people without sickle cell, the levels of the inflammatory markers rose higher during the exercise period, Subsequently, after stopping exercise, they dropped back to baseline levels again during the recovery period. What was interesting was that the the size of the increase in the concentration of the markers, as well as the time they took to return to baseline values, were very similar in both the sickle cell patients and the normal, control subjects.

These results are reassuring; although baseline inflammatory markers are raised in people with sickle cell the pattern of change seen during and after maximal exercise is very comparable in both patients and control subjects. Provided that you follow simple rules – keep warm and well hydrated, before, during and after exercise and build up exercise levels gradually – it is safe for young people with sickle cell to exercise as hard as they can. Certainly, running around the playground at school, playing football or basketball or going to the gym is something that all sickle cell patients should be able to enjoy. On the basis of this study there is no reason why patients with sickle cell should be denied the important and well described benefits of regular exercise.

The acute phase inflammatory response to maximal exercise testing in children and young adults with sickle cell anaemia. Liem RI, Onyejekwe K, Olszewski M, Nchekwube C, Zaldivar FP, Radom-Aizik S, Rodeghier MJ and Thompson AA. British Journal of Haematology, 2015, volume 171, pages 854-861

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About rogerjamos

I am a consultant haematologist who has worked in Hackney, London, UK with patients who have sickle cell disease for many years. Knowledge is power; the hope is that this blog will empower patients by putting them in touch with contemporary research into sickle cell disease and facilitating informed discussion on the issues raised. Dr Roger Amos MA, MD, FRCPath
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