Research has shown that effective results are seen from the 20th training session and the beneficial hypotensive effects last up to 14 weeks even after exercises have been stopped
FAPESP AGENCY – O strength training practiced with a moderate to vigorous load, two or three days a week, is a good strategy for reducing blood pressure. The conclusion is drawn from a Brazilian study published in the journal Scientific reports.
The mechanisms of blood pressure decrease through aerobic activities have been well studied. However, there are few investigations into strength training, such as that conducted by researchers at the Universidade Estadual Paulista (unesp).
Under the coordination of Giovana Rampazzo Teixeira, professor at the Department of Physical Education of Unesp in Presidente Prudente, the group conducted a systematic review of the scientific literature on the subject with meta-analysis – a type of study considered the gold standard in terms test. The goal was to test the intensity, volume and duration of training that would guarantee the best results.
The research had the collaboration of researchers from the University of São Paulo (USP) and was funded by the São Paulo Research Foundation (FAPESP) through three projects.
Cardiovascular diseases are the leading cause of death worldwide and arterial hypertension accounts for 13.8%. The condition is considered a problem when mercury levels are above 140 millimeters of systolic blood pressure (mmHg) and above 90 mmHg of diastolic blood pressure. It is a multifactorial disease, triggered by habits such as a sedentary lifestyle, poor diet, alcohol consumption and smoking.
It was already known that strength training was a therapeutic option, but until then there was little certainty about the most effective protocols. With a sample of 253 participants, with an average age of 59, the analysis was based on a series of controlled studies that evaluated the effect of training for eight weeks or more.
“We focused on establishing the volume and intensity that was sufficient to achieve a significant reduction in blood pressure readings. On average, strength training performed over eight to ten weeks was sufficient for a 10 mmHg reduction in systolic and 4.79 mmHg diastolic”, Teixeira tells Agência FAPESP.
The study showed that effective results were observed around the 20th training session and that the beneficial hypotensive effects lasted up to 14 weeks even after the exercises were stopped, the so-called detraining phase.
“In clinical practice or even in daily life in gyms, professionals who come across a hypertensive subject will be able to use strength training as a non-pharmacological treatment of arterial hypertension, knowing which variables are necessary for this to be achieved and always keeping account of the person’s goals,” explains the researcher.
systematic analysis
For a long time, aerobic training alone was indicated for the treatment of arterial hypertension and, therefore, molecular studies have been almost entirely restricted to this modality.
“Recently, strength training entered the Brazilian guidelines on arterial hypertension, but much still needs to be investigated in order to have more solid evidence. The perspectives of new studies are based on the molecular mediators responsible for this reduction in blood pressure vascular and blood during strength training,” reflects Teixeira.
The systematic review was how the researchers were able to analyze the breadth and robustness of the evidence on the potential of strength training. Previous reviews have verified that there was some effect, however, the now published work provides important additional evidence, such as load intensity, volume and weekly frequency. The researchers initially pooled 21,132 articles, of which 54 met the criteria for full-text analysis. Of these, 14 were considered relevant for review.
The most beneficial effect was observed in protocols with moderate to vigorous intensity loads, greater than 60% of the load used for one repetition maximum, the most intense supported by the individual. That is, if the maximum load you can do a single repetition with is 10 kilos, the most beneficial training load was above 6 kilos. Another important observation was to confirm that the frequency should be at least biweekly, maintained for at least eight weeks.
Most of the studies in the review involved people aged 60 to 68, with only two studies including a younger population (18 to 46 years). Seven studies included patients of both sexes, in seven other studies the sample consisted only of women and one of the studies included only men.
Looking at the subgroups, it was also found that the effect of the intervention was related to age. Those aged 18 to 50 had markedly greater blood pressure lowering effects than the age group 51 to 70. “However, strength training can be done at any age, because there are hypotensive benefits even in older people,” the researchers attest.
Future studies should unravel the cellular and molecular mechanisms responsible for the decrease in blood pressure as a result of strength training. What is known is that during physical activity there is an increase in heart rate, an increase in the diameter of blood vessels (vasodilation), greater blood flow and an increase in the production of nitric oxide (a compound with a vasodilating effect). Over the long term, exercise promotes adaptations, such as a decrease in resting heart rate, an improvement in cardiac efficiency, and an increase in the maximum volume of oxygen the body can absorb with each breath (VO2max).
Among the limitations highlighted by the researchers is the inclusion of patients who used antihypertensive drugs in 11 of the 14 studies, such as ß-blockers, diuretics, calcium channel blockers and angiotensin converting enzyme inhibitors. There is also the fact that some articles use men and women in the same intervention group, which prevents analysis by gender.
The article can be accessed in this link.
Source: Terra