Author: Dr David Glass

A multipronged intervention on the “silent killer”.

What do you think is the most prevalent non-communicable disease in South Africa? It was reported in 2016 to affect nearly 48% of the adult population, and is more common in males. (1) I am not aware of any more recent research of prevalence, but it may well be even higher, in line with world-wide trends. The answer, hypertension – defined in our South African guidelines as 140/90 mmHg or more, on repeated testing.

Because it is so common and so many people appear to live a normal life with the diagnosis, the risks are often ignored. Yet hypertension is the main cause of stroke, heart failure, and heart attack, and can contribute to vision loss, kidney disease/failure, and sexual dysfunction.(2)

Factors contributing to hypertension include age (incidence rises with age), genetics, obesity, sleep apnoea, lack of physical activity, dietary factors, alcohol excess and various medications (corticosteroids, non-steroidal anti-inflammatory drugs (NSAIDs), antihistamines, diet pills, oral contraceptive and some antidepressants). Uncommon underlying diseases associated with hypertension include Conn’s syndrome, Cushing’s disease, thyroid disorders, hyperparathyroidism, phaeochromocytoma, kidney disease and coarctation of the aorta. (3)

The 2014 South African Hypertension Guidelines state: “Lifestyle modification and patient education are cornerstones of management.” (4) (Emphasis supplied) Every well-trained doctor knows that pharmacological management is vitally important and can be lifesaving in severe hypertensive crises, and certainly help to reduce complications and reduce mortality in the long term. However, side effects of medications are common, and a significant number of patients stop their medications because of side effects. The lifestyle modifications are cost-effective, and not only benefit hypertension, but also reduce the risk of atherosclerosis, diabetes, obesity, hyperlipidaemia, and cancer, apart from increasing the general feeling of well-being. “The British Hypertension Society guidelines advocates maintenance of normal body weight, consumption of a diet rich in fruit and vegetables, and reduced total and saturated fat…these interventions can reduce the need for drug therapy, enhance the effect of antihypertensive drugs, reduce the need for multiple drug regimens, and favourably influence overall cardiovascular risk.” (5)

Although not explained in much detail, the South African Hypertension guideline’s (4) recommended lifestyle changes do outline the potential reduction in systolic blood pressure (SBP) which may result from the different interventions. Weight reduction can reduce SBP by 5-20 mmHg per 10 kg lost; a DASH (Dietary Approaches to Stop Hypertension) diet (decreased saturated and total fat, and increased fruit and vegetables) can reduce SBP by 8-14 mmHg; decrease of dietary sodium to less than 100 mmol or 6 g NaCl/day, may reduce SBP by 2-8 mmHg; brisk walking for 30 minutes most days, SBP down by 4-9 mmHg; reduction to 2 or less alcoholic drinks, for those who drink alcohol, can reduce by 2-4 mmHg. All these can add up to significant reductions in blood pressure when combined just from lifestyle modifications, and may well require the treating doctor to decrease, or even stop some or all medications.

“The DASH trial was the first major randomized controlled trial to evaluate the effects of a mostly plant-based diet on BP. It was created to ‘have the blood pressure-lowering benefits of a vegetarian diet, yet contain enough animal products to make [it] palatable to nonvegetarians.’” (6) However, there is much evidence showing the superiority of a whole food plant-based diet compared to both the Mediterranean as well as the DASH diet in preventing and controlling hypertension. A very comprehensive article was published in 2020 in the American Journal of Lifestyle Medicine which explains the very many biochemical reasons for this advantage. (7) It is well worth the time spent reading it.

Specific dietary guidelines:

1. Reduce salt in the diet. The most common source of sodium in the diet is from processed foods like snack chips, French-fries, tomato sauce, fast foods, cheese, pizza. The last three are also rich in saturated fats and Advanced Glycation End products (AGEs). (7) Can reduce BP by 5-8 mmHg.

2. Increase potassium containing foods: (8)

3. Fruits – bananas, avocados, grapefruit, oranges, prunes, raisins, dates, tomatoes.

4. Vegetables – spinach, beetroot, rocket, Swiss chard, sweet potatoes, potatoes, broccoli, beans, lentils, peas, cucumbers, zucchini, leafy greens (also rich in nitrates which can increase nitric oxide), onions, garlic, mushrooms.

5. Whole grains – brown rice, whole-wheat bread (but check the sodium content), whole-wheat pasta.

6. Cut out or significantly reduce foods of animal origin – red and white meat (especially processed meats), dairy, eggs, cheese. (7,9) Can Reduce BP by 11 mmHg.

7. Eat ground flaxseeds (linseeds) 2-3 tablespoons per day – mixed with cereals or in a shake. Can reduce BP by 10-15 mmHg. (10)

8. Cut down on oil, especially saturated fats. Avoid fried foods, roasted foods, fast foods and fatty restaurant foods. The healthiest oils are found in the whole plants – olives, avocado, nuts and seeds. (11)

9. Some authorities have suggested avoidance of caffeine, but the elevated blood pressure in some people seems to be related to substances in coffee rather than the caffeine, as decaffeinated coffee raised BP more than the equivalent caffeine levels given intravenously found in normal coffee. (12)

10. Avoid alcohol – rather drink red grape juice or water. (13)

11. Watermelon appears to have extraordinary effects but you need to eat around 1 kg per day! (14)

Physical activity and hypertension:

Multiple studies from many countries have shown the inverse relationship between physical activity and hypertension. (15) This has been found with both medium-to-high-intensity aerobic exercise (by a mean of 11/5 mmHg), as well as isometric or static activity. (16). Physical activity protects cardiovascular function in multiple ways. (17) Exercising as little as 1 day per week is as effective (or even more so) than first line pharmacotherapy for reducing all-cause mortality among those with hypertension. Exercise is equally effective as medications in mortality outcomes for coronary heart disease and prediabetes, and actually more effective for secondary prevention of stroke mortality. As a result numerous international guidelines recommend exercise for the prevention, treatment, and control of hypertension. (18)

How to write an exercise prescription?

The prescription is designed around the individual patient in terms of Frequency (how often?), Intensity (how hard?), Time (how long?), and Type (what kind?) – the FITT principle. Broad principles in prescribing exercise: A biokineticist can give further guidance.

• Frequency – recommendations at least 3-4, preferably 7 days per week. A physiological response called postexercise hypotension (PEH) can result in a drop in BP by 5-7 mmHg, which can last up to 24 hours. Start gently and increase gradually.

• Intensity – the greater the intensity the better the response – but start gradually and build up. High intensity interval training has been shown to have better cardiovascular benefits in obese, metabolic syndrome, coronary heart disease and congestive heart failure patients.

•  Time – most professional organisations and committees recommend at least 30 minutes, with minimum of 150 minutes moderate exercise per week. But this can also be accomplished with a number of short 10 minute bouts per day.

• Type – there is broad consensus that aerobic exercise is the most important, however increasing evidence suggests dynamic resistance training on 2-3 days per week may also be beneficial. (18)

Stress reduction and Social relationships

“Substantial evidence indicates that chronic psychosocial stress contributes to hypertension, cardiovascular disease (CVD), and cardiovascular mortality. It is as much a risk for myocardial infarction as smoking, obesity, and diabetes”. The mechanism through which chronic stress elevates blood pressure is through persistent hyperactivation of the sympathetic nervous system and hypothalamic-pituitary-adrenocortical axis. (19) Of the various methods of stress reduction investigated in the above study, only Transcendental Meditation showed any statistical effect in reducing BP.

An area that shows great promise in both preventing and managing chronic diseases is positive psychology. Although still in its infancy in terms of long-term research, we do know that living with purpose and with a sense of optimism promotes healthful behaviours. Positive psychology incorporates such attitudes and perspectives as positive emotions, life satisfaction, optimism, forgiveness, self-regulation, vitality and zest, life meaning and purpose, helping others and volunteering, good social relationships and spirituality and religiosity. (20)

Adequate and restful sleep in blood pressure management

Not enough research has been done to establish how much benefit derives from normalising sleep patterns in managing hypertension. However, we do know that inadequate sleep reduces night-time BP dipping, and results in increased cardiovascular risk. We also know that “habitual short sleep duration is associated with hypertension, especially during middle age”. Obstructive sleep apnoea is also associated with hypertension. Obstructive sleep apnoea can be caused by obesity – in itself a risk factor for hypertension, so also needs to be addressed. (21). The recommendations are for 7-8 hours sleep a night for adults. It is important to establish whether this is being achieved in your hypertensive patient.

Addictive substances and medications associated with hypertension

It is well known that alcohol excess is strongly associated with hypertension, (22) thus it is important to gently probe into the patient’s drinking habits, and with their permission address problem drinking. Although smoking has not been found to directly affect blood pressure, there is no doubt that it is a major contributor to cardiovascular risk, so is important to discuss. In our introduction, we mentioned a whole array of medications that can contribute to hypertension, and thus a careful history of therapeutics must be obtained, and re-assessment of prescribed medications to reduce risk. (23)

Providing a wholistic prescription:

In an article in the British Journal of General Practice already in 2010, the following statement was made: “It is generally agreed that the greatest chance of success with diet and behavioural modification is achieved with clear written and verbal explanations, a chance for the patient or their carer to ask questions and talk through potential problems, regular monitoring and follow-up, and a support group to encourage compliance. Referral to a dietician, nutritionist, or experienced nurse [and perhaps a biokineticist/physiotherapist] would clearly be beneficial….The advantages include a significant drug cost reduction, a beneficial effect on other conditions, such as diabetes and hypercholesterolaemia, and avoidance or delay of drug treatment with its potential for adverse effects. ” (24)

After taking a careful history and examining your patients, it is worthwhile giving a general overview of factors contributing to their specific hypertension. Assess with them what lifestyle factors they would be willing to work on, and develop together with them a practical plan of action. Remember you are not concentrating on the destination, but the journey. Do not overwhelm them trying to address every lifestyle factor, but be sure to identify achievable objectives.

Use the 5 A’s approach:

• Assess health behaviours;

• Advise to change with clear, specific, personalised advice;

• Agree on focus of treatment based on the patient’s perspectives;

• Assist the patient in setting and achieving goals;

• Arrange regular follow-up and support.

Conclusion:

Hopefully this article will provide a more practical perspective on how to implement lifestyle

behaviour changes in managing your hypertensive patients.

Dave Glass
MBChB, FCOG(SA), DipIBLM