This is the first trial to assess the effects of training in the interval exercise on 24 -hour blood pressure and arterial stiffness in hypertensive subjects receiving long -term treatment. The main observation was the observation that the training of the exercise, regardless of the exercise training method, decreased blood pressure on the ABPM. In addition, only interval training has improved arterial rigidity as evaluated by a decrease in the carotid-femoral PWV.
Blood pressure
It is well known that aerobic exercise decreases blood pressure, mainly during the day. These hypotestrative effects are more pronounced in hypertensive patients.14,, 15,, 16,, 17
A meta-analysis has shown that aerobic exercise decreases systolic and diastolic blood pressure by 6.9 and 4.9 mm Hg, respectively, in hypertensive patients against. 2.4 and 1.6 mm Hg in normanatend subjects.15 Another meta-analysis, which included ambulatory measures of blood pressure, has shown that aerobic exercise decreases the systolic / diastolic blood pressure by 4.5 / 2.4 mm Hg during the day and 1.7 / 0.7 mm Hg during the night.18 Our study is in accordance with these results; Blood pressure in our subjects has decreased during the day, mainly in those who have higher blood pressure values.
Some studies have analyzed the effects of the various intensities of the training of the exercise on blood pressure. These studies have shown that the intensity of the exercise does not influence the level of drop in blood pressure.7,, 18 Our study agrees with these results and shows that the intensity of the exercise does not influence the decrease in blood pressure.
Several factors are involved in the decline of the blood pressure mediated by training the exercise, but the improvement in peripheral vascular resistance seems to have the most important role. The decrease in the sympathetic activity of the nervous system,19 Effects on Baroreflex control20 and improvement of the production and action of nitric oxide (endothelial function)21 are probably involved in the anti-hypertensive effects of the exercise. In addition, the effects on arterial reshaping,22 angiogenesis23 and arterial dissensibility24 could be linked to the drop in blood pressure after training in aerobic financial year.
Stiffness
The aging process leads to a gradual increase in arterial rigidity, especially in large arteries, as has been clinically observed in elderly patients. Indeed, in hypertensive subjects, this increase is more pronounced.25 Aerobic exercise training seems to reduce arterial stiffness in healthy subjects, but results in hypertensive patients are controversial.25 Twelve weeks of aerobic practice, to 70 to 75% of the maximum heart rate, increased the carotid compliance of healthy subjects to the same values ​​as men formed by endurance.2 However, 8 to 12 weeks of aerobic exercise at 65 to 70% of the maximum heart rate have not improved arterial rigidity in patients with systolic hypertension.24,, 26 In our study, after 16 weeks of training, arterial rigidity, measured by PWV, only decreased in the training group by aerobic intervals. The intensity of the exercise and the severity of the disease could explain these contradictory results.
The mechanisms involved in arterial rigidity are the degradation of the elastic matrix, endothelial dysfunction, hypertrophy and hyperplasia of smooth muscle cells and the increase in collagen content.27,, 28 These mechanisms seem to be more accelerated in hypertensive subjects.28,, 27 On the other hand, an experimental study has shown that the extent of the distension of the wall favored by a given shear constraint affects the change in arterial rigidity by the mechano-biochemical signaling which compromises the vasorelaxation.29 Thus, training in aerobic exercise with an increased intensity or duration should be necessary to better improve arterial stiffness in hypertensive subjects. Nevertheless, in healthy subjects with less rigid arteries, a short duration and a low exercise intensity could be sufficient to improve arterial function.2,, 4 In this context, an aerobic exercise with increased intensity may be necessary to improve arterial rigidity in hypertensive subjects, as observed in our study. As younger subjects can have less rigid arteries and that they can react with greater drop in PWV, it could be said that a 5 -year difference between continuous training and the interval may have influenced the results. However, this age difference was not statistically significant. In addition, we did not find a significant correlation between the age and the fall of PWV.
Clinical implications
The reduction in blood pressure after the two drive protocols, although observed mainly in people with higher basic levels, has significant clinical implications because it has been documented that a reduction of only 2 mm Hg of systolic blood pressure reduces the mortality of vascular cerebral accidents by 10% and a 7% cardiovascular disease.30
Arterial stiffness has proven to be an independent predictor of cardiovascular mortality and all causes31 in hypertensive patients. Sedentary lifestyle and anti-hypertensive treatment led to an increase of 0.8 m−1 from PWV in 6 years.27 Our study shows that only 16 weeks of interval training caused a drop in PWV of 0.41 ms−1 in a similar population.
Regular physical activity is an effective intervention in relation to these factors, which reduced the mortality rate for cardiovascular disease and all causes of diseases in hypertensive patients,32 alleviate the increase in arterial rigidity associated with age,2 as well as the reduction in genetic sensitivity to this increase.33 In addition, physical activity helps control the metabolic variables linked to hypertension and arterial rigidity.34
Study limitations
This study has several limits. The percentage of membership in training the financial year was 61% for the interval and continuous groups, which is a low level of membership. There were two supervised training sessions per week; However, the patients were invited to carry out an unleanished exercise session. However, it has been shown that there is no significant difference in reducing blood pressure between a training program for the exercise requiring two sessions per week compared to three sessions.35 In addition, we do not know if our results would have been different for those whose hypertension was controlled in relation to those suffering from uncontrolled hypertension.
Prospects
The interval and continuous practice training have been well tolerated in chronic hypertensive subjects treated with anti-hypertensive drugs. The blood pressure control has improved with exercise training, but only the interval exercise has improved arterial rigidity, measured by PWV analysis, which reaffirms the need for the inclusion of physical activity in the treatment of hypertensive patients.
