It may seem paradoxical, but the truth is that it is not harmful to increase your heart rate if you have high blood pressure while exercising. In fact, exercise helps lower blood pressure and reduce risk factors that cause chronic disease. Of course, not all types of physical activity contribute equally. The mechanisms linking blood pressure reduction to aerobic exercise (such as running, swimming, or cycling) are well studied, but the effects of resistance exercise on high blood pressure have been little studied.
At first, one might think that this modality could be harmful. However, it has long been known that it is a treatment option for high blood pressure. Until now, it hasn’t been clear what guidelines need to be followed for resistance training to be beneficial in treating high blood pressure. Hence the importance of a recent study published in the journal Scientific Reports that determines the best way to carry it out.
It should be noted that cardiovascular diseases are already the main cause of death worldwide. Specifically, high blood pressure is responsible for 13.8% of deaths of this type. This condition is diagnosed when systolic blood pressure exceeds 140 millimeters of mercury (mmHg) and/or diastolic blood pressure exceeds 90 mmHg. It is a multifactorial disorder caused by problems such as unhealthy diet, excessive alcohol consumption, smoking and lack of exercise.
The study in question was conducted by the State University of São Paulo (UNESP) in Brazil. Through this work, resistance training performed two to three times per week at moderate to vigorous intensity has been shown to be an effective means of relieving high blood pressure.
Led by Giovana Rampazzo Teixeira, professor at UNESP’s Department of Physical Education in Presidente Prudente, the group reviewed more than 21,000 scientific articles and conducted a Cochrane meta-analysis, considered the gold standard of systematic reviews. According to the authors, the analysis focused on the effects of variables such as age, dose-response training, load, volume and frequency of resistance training.
Blood pressure remained lower for 14 weeks after training stopped
In this study, the sample consisted of 253 hypertensive subjects with a mean age of 59.66 years. The meta-analysis focused on hypertension responses at baseline and post-exercise in controlled trials assessing the effects of exercise for eight weeks or longer.
“We were particularly interested in what volume and intensity were considered sufficient to achieve a significant reduction in blood pressure. On average, eight to ten weeks of resistance training resulted in a reduction in systolic blood pressure of 10 mmHg or 4.79 mmHg in diastolic state,” Teixeira told the São Paulo State Research Protection Foundation Agency (FAPESP).
The study showed that effective results occurred after about the twentieth training session. Blood pressure remained lower for about 14 weeks after training stopped. “In clinical practice and in gyms or fitness centers, resistance training as a non-pharmacological intervention can be a treatment option for people with hypertension, provided the key variables are sufficiently known and the goals are taken into account,” explains Teixeira.
For high blood pressure, moderate to vigorous intensity is best
This study is innovative because it collected additional evidence on the influence of age, load, intensity and frequency of exercise. After excluding 21,035 articles that did not meet the objectives of the review, researchers analyzed 54 articles. Fourteen were considered relevant for inclusion in the systematic review. The results showed that resistance training was most effective in lowering blood pressure when protocols were performed with a moderate to vigorous exercise intensity, a frequency of at least twice a week and a minimum duration of eight weeks.
A moderate-to-vigorous load intensity was defined as more than 60% of the heaviest weight the subjects could lift at a time, known as a one-repetition maximum or 1RM, so that a 1RM of 10 kilograms represented the most effective workout. The load would be more than 6 kg .
A subgroup analysis revealed more about the influence of age on the effect of strength training, which reduced blood pressure significantly more in the group of 18 to 50 year olds than in the group of 51 to 70 year olds. “Strength training can definitely be done at any age. The effect on blood pressure is also beneficial in older people,” clarified Texeira.
For a long time, only aerobic exercise was prescribed to treat hypertension, and molecular studies focused almost exclusively on the effects of this type of exercise. “Strength training was recently included in the Brazilian guidelines for the treatment of high blood pressure, but much more research is needed to obtain more solid evidence,” adds the professor.
In their opinion, future studies should therefore investigate the cellular and molecular mechanisms responsible for the drop in blood pressure in response to resistance training. Current evidence shows that it increases heart rate, increases production of nitrous oxide, which promotes vasodilatation by expanding blood vessel diameter and promotes blood flow.
In the long term, it facilitates adaptations such as a lower resting heart rate, lower blood pressure, higher cardiac output and a higher VO2max, which is the maximum oxygen consumption rate that can be achieved during intense exercise. VO2max is typically measured in milliliters of oxygen consumed per kilogram of body weight per minute (ml/kg/min) and is relevant to cardiovascular health.
Limitations of the analysis noted by the authors include the inclusion of patients taking antihypertensive medications such as beta-blockers, diuretics, calcium channel blockers, and angiotensin-converting enzyme inhibitors (ACE inhibitors) in 11 of the 14 studies. Furthermore, in some studies the inclusion of men and women in the same group prevented a gender-sensitive analysis of the effects of resistance training.
