Last week I described the nature of a stroke, the underlying causes and some of the devastating consequences. Prevention and early treatment are needed to avoid some of these consequences. Long-term problems are very frequent in stroke survivors and include mobility difficulties (58 per cent), fatigue (52 per cent), loss of concentration (45 per cent) and falls (44 per cent).
Exercise in the prevention of thrombotic stroke
Regular exercise reduces several of the factors that are known to be the most important provokers of strokes – obesity, high blood pressure, dyslipidaemia and type 2 diabetes. It would be impossible to carry out a long-term, large-scale randomised controlled trial of exercise for stroke prevention, but observational studies confirm that the incidence of stroke is between 20 per cent and 70 per cent lower in those who are physically active compared with those who are not. Moreover, these studies have shown that there is a dose-response relationship between the amount of exercise taken and the reduction in risk. Both duration and frequency of exercise are related to the reduction in risk – the longer you exercise and more often you do it, the more you reduce your stroke risk.
As you might expect, therefore, physical fitness is also closely related to stroke risk. For instance, slow walking pace in the over-65s carries an increased risk of stroke. One study of over 16,000 healthy men showed a striking relationship between greater cardiorespiratory fitness and lower stroke mortality. Those in the high-fitness group had less than one third the risk of dying from stroke of those in the low-fitness group. A study from the Cooper Institute in Dallas, Texas, followed 20,000 adults who had been fitness-tested and found a similar dose-response relationship between physical fitness and stroke risk – that is to say, the fitter the subject, the lower the risk.
This week’s illustration is a histogram showing the risk of stroke at different levels of fitness. In this case the incidence of stroke in the lowest fitness group is six times greater than in the fittest group.
Exercise in the immediate treatment of stroke
The untreated stroke patient experiences a spontaneous improvement over the following weeks and months. Mildly affected individuals may recover completely while more severely affected patients never regain their previous levels of function, though improvement can continue for many months.
The cornerstone of post-stroke treatment is physiotherapy to encourage use of the affected muscles and the best possible return of their strength. This applies to all strokes, whether thrombotic, embolic or hemorrhagic. There has been little research into the optimal frequency and duration of physiotherapy for post-stroke rehabilitation but what evidence there is indicates that more is better.
Unfortunately, stroke rehabilitation in the NHS is usually grossly under-resourced, with patients seldom receiving adequate physiotherapy. Being in hospital is almost designed to reduce strength and mobility – 10 days in hospital is said to be equivalent to 10 years of ageing. Hospital culture encourages lying and sitting rather than being active, driven by the desire to prevent falls in under-staffed wards. The sitting or lying patient is less dangerous to him/herself than the mobile patient. Rehabilitation therefore has to be intense to overcome the de-training effects of just being in hospital. The sooner the patient can be got home and returned to normal daily activities, the better.
A story of how it can be done
A model of stroke rehabilitation was provided by Roald Dahl. In 1965 his wife, actress Patricia Neal, had a disabling stroke caused by a brain haemorrhage. She was left with a severe speech impediment and one-sided weakness. Dahl feared she would become an ‘enormous pink cabbage’, so with his friends and neighbours he set up an intensive 6-hours-a-day regime of physical activity and speech retraining. Some professionals warned this was too much, but he ignored them. Pat was coached back to normality, ‘slowly, insidiously and quite relentlessly’. She eventually resumed her acting career, even getting another Oscar nomination.
Next week I will talk more about exercise after stroke and also the prevention of embolic stroke.