Physical activity recommendations for avoiding hypertension and its complications

Every hypertension guideline in recent decades has recommended lifestyle measures including increased physical activity as part of first line management for people with hypertension [1–3]. Prior to the 1980s and particularly in the era prior to the availability of antihypertensive pharmacotherapy, people with hypertension were recommended bed rest. Since then, the evidence for benefit of physical activity both in the prevention of hypertension, its management and the progression of cardiovascular disease has strengthened progressively. The only missing link in an otherwise coherent and compelling evidence base is a large randomized controlled trial with hard outcomes. That is probably impossible but in the meantime we have experimental data, short-term randomized controlled trials, evidence of mechanisms, dose–response, and long-term cohort studies all pointing to a few simple conclusions. A little bit of exercise is better than a sedentary life for everyone, including people with hypertension, moderate intensity exercise is even better. It may not matter what kind of exercise is performed but the best evidence is for traditional forms of aerobic exercise, dynamic resistance and combined forms. Some benefits albeit sub-maximal can be achieved in a variety of ways with no apparent lower threshold of activity, and no need to achieve the ideal and recommended targets. The recent American College of Sports Medicine Physical Activity Guidelines for Americans and the accompanying evidence review summarizes the present state of knowledge on hypertension and physical activity based on meta analyses and systematic reviews involving 125 986 adults. It concludes there is ‘strong’ evidence for reduction in progression of cardiovascular disease with increased physical activity above sedentary levels based on effects on blood pressure and on mortality. The evidence review goes further pointing to many other benefits ranging from better sleep, reduced risk of depression and reduction in symptoms of depression or anxiety, improved executive and physical function, improved insulin sensitivity, reduced weight gain, dementia and falls as well as lower rates of breast, colon, bladder, endometrium, oesophagus, kidney, lung and stomach cancer. On the other hand, there are risks, mostly musculoskeletal, cardiac, heat injuries and infections but these are far outweighed by the benefits at the level of public health [4]. Taking all this at face value, physical activity is indeed a magic potion and one we would expect to be embraced by physicians managing people with hypertension worldwide. Yet anecdotally one hears that lifestyle measures including physical activity recommendations are ineffective in daily practice as they are rarely taken up by patients and they are rarely maintained. This is no doubt true for the most part but what conclusions can be drawn from this experience? Is it that physical activity is not that effective despite the data or is it that we are not that good at prescribing it and supporting patients maintain healthy habits in daily life? What is clear is that an individual physician advising an individual patient to ‘get more exercise’ is not enough [5]. However, from the busy treating doctor's perspective, if anything is required more than brief advice it may be easier to write a medication prescription. There are proven techniques for improving adherence to physical activity recommendations. In the individual, these are largely based on behaviour change theory. School-based and community wide programs have been shown to be effective and more recently support provided through wearable devices, IT applications and telemedicine. It is important to understand that behaviour change is a process rather than a single event that occurs like a flash of light during a hypertension review consultation. There will always be gaps between intention and action and between initiation and maintenance. On any given day, the decision to go for a walk, run, attend the gym, and so forth is one of thousands of small interrelated decisions. Supporting an individual to increase their physical activity, therefore, requires a sustained approach that considers their readiness, mores, capabilities and environment. As physicians, we need help to do this, perhaps by engaging an exercise physiologist, or by adopting models used in other fields, such as diabetes care with multidisciplinary teams constituting educators, nutritionists and other health professionals [4,5]. In the public health arena, there are upstream opportunities for reduced incidence of hypertension through increased physical activity. An example of this is provided in the report from Kunutsor et al.[6] from Finland reporting reduced hypertension incidence related to cross-country skiing in a cohort of 1809 men aged 42–61 years and no known history of hypertension at baseline followed over a median of almost 25 years. The study has the usual strengths and weaknesses of a cohort study including the inability to attribute causality and the possibility of residual confounding. These people presumably selected themselves for this activity and selection bias, or even genetics cannot be ignored (17% of the original cohort declined to participate). Nevertheless, there was a continuous inverse and independent relationship between the amount of leisure time cross-country skiing recorded at baseline and incidence of hypertension over the next 20 years. This relationship was stronger than that with overall leisure time physical activity. The approach to assessing physical activity was particularly rigorous albeit by using a questionnaire, a modified Minnesota Leisure-Time Physical Activity questionnaire. Participants recorded the frequency, average duration and intensity of each type of physical activity performed. From this, the investigators were able to impute the ‘dose’ or volume of exercise based on the commonly used FITT approach (frequency, intensity, time, type). Both volume and frequency of leisure time cross-country skiing were related to incident hypertension and also to incident diabetes. This result in healthy middle-aged male Finns is complementary to the finding in a cohort of 26 643 middle-aged Finns with obesity and hypertension again followed for over 20 years [7]. Here the hazard ratio for cardiovascular mortality in middle aged men who regularly undertook any kind of moderate intensity exercise defined as 12 METs/h was 0.84 compared with those who did no or little exercise. The hazard ratio associated with regular high intensity exercise with the same comparator was even lower at 0.73. The corresponding figures in women were similar at 0.76 and 0.78, respectively. The question arises as to whether there is anything special about cross-country skiing or whether this is an example of yet another form of physical activity having benefits for cardiovascular disease. Certainly, the hazard ratio at the highest volume of activity was lower than that seen in the cohort with hypertension and obesity doing other forms of exercise. Competitive cross-country skiers have the highest recorded levels of maximum oxygen uptake (VO2max), implying they are the fittest in aerobic terms amongst competitive athletes [8]. The exercise involves upper and lower limb movements and mobilizes practically every muscle in the body. Skiing volume was assessed at entry as a snapshot but not followed up. Blood pressure was measured carefully at entry using the standard techniques at the time but incident hypertension was assessed using either hospital or medication records all of which would add some noise to the analysis. In summary, the evidence for physical activity providing protection against both the development of hypertension and the cardiovascular consequences of established hypertension is overwhelming and cross-country skiing can be added to the range of modalities that are a pathway to these benefits. These potential benefits are too great to be dismissed and physicians need to do more to ensure that these are realized in daily practice. These efforts can include advocacy for public health measures, such as a more exercise-friendly built environment and transportation, addressing sedentariness in homes, schools and workplaces and improved health literacy on the importance of avoiding hypertension through healthy living. Physical activity advice and even a physical activity prescription are as important a part of a hypertension consultation as medication advice and prescription. If time does not allow a full discourse, there are many other potential avenues including practice nurses, multidisciplinary teams and community groups that can help elaborate, emphasizing that in an increasingly sedentary world, any physical activity is better than none at all, and if there is no snow outside there are plenty of other alternatives. ACKNOWLEDGEMENTS Conflicts of interest There are no conflicts of interest.