Effects of progressive muscular relaxation and stretching exercises combination on blood pressure among farmers in rural areas of Indonesia: a randomized study^†

The prevalence of hypertension in Indonesia is 26.5%.¹ While the prevalence of hypertension systolic and hypertension diastolic among farmers is 45.2% and 35.8% respectively, both are correlated to worked overload.² Provision of screening programs, health education programs, including dietary programs, and physical and exercise programs prevented and reduced health problems among farmers in the agricultural sector.³ Stretching exercise (SE) and progressive muscle relaxation (PMR) are effective interventions for maintaining health status, in particular, blood pressure (BP).^4,5,6 Therefore, the PMR and SE are used as alternative program therapy to maintain BP among agricultural farmers.

As one of the behavioral techniques, PMR is used to reduce stress and anxiety^7,8 by focusing on movements to contract and relax muscles for controlling pain⁹ and improving mental state.⁶ Practically, PMR is used to reduce stress on various physical and mental problems. This technique was developed by Jacobson in 1934¹⁰ and later adapted by Berstein and Borkovec in 2000.¹¹ The working mechanism of the PMR technique is to focus on the difference between feelings of anxiety and stress and relaxation.^7,8,9,10,11 Controlling of feelings causes relaxation and reduces self-pressure,¹² thus controls the hemodynamic of BP. Therefore, PMR is very safe and easy for behavioral intervention and this is highly recommended, because it does not require special expertise of techniques.¹²

Although the SE is a form of exercise for maintaining muscle fitness and elasticity,¹³ the mechanism of action of the SE will increase muscle flexibility and maintain blood circulation in the blood vessels smoothly by maintaining blood vessel elasticity.¹⁴ Hemodynamic conditions, heart rate, and BP can be controlled optimally through regular SEs.¹⁵

Lifestyles, characteristics of working conditions, and the environment are associated with farmers’ health problem³ and these factors influenced the quality of life among farmers in agricultural health,¹⁶ especially in maintaining their BP. Previous studies mentioned that the PMR was effective in decreasing systolic blood pressure (SBP) and diastolic blood pressure (DBP),¹⁷ whereas the SE reduced peripheral and central BP.⁵ Using a combination of PMR and SE is an important strategic intervention for maintaining BP among farmers.

In addition, rural areas of Indonesia are an administrative area at the village level that does not meet certain requirements in terms of population density, percentage of agricultural households, and a number of urban, formal education, and public health facilities.¹⁸ The characteristics of urban areas of Indonesia are marked by the very large role of primary groups, whereas geographical factors determine the formation of community groups, relationships are more intimate and durable, social structures are homogeneous, social mobility is low, families are more dictated by their functions as economic units, and the proportion of children is quite large in population structure.¹⁹ Meanwhile, farmers in Indonesia are individuals or groups of farmers who work in the agricultural sector by carrying out various cultivating activities in agricultural fields in rural areas and they spent the most time of day-to-day activities in the fields to produce products from agriculture.²⁰ Farmers are at-risk for health problems because of their lifestyle and hazards in agricultural areas,³ including hypertension.²¹ Therefore, BP should be maintained for improving the healthy life among farmers.

Furthermore, controlling BP among farmers is useful for improving their health status. Maintaining BP could the improve quality of life among farmers for supporting their health and safety in agricultural health. Therefore, this study aims to evaluate the effects of PMR and SE on the BP of farmer subjects in rural areas of Indonesia.

Among 155 participants assessed for eligibility in this study, 25 participants were excluded from the study (not meeting inclusion criteria = 11 and declined to participate = 14). Then, a total of 130 participants participated in this study. The 130 participants were allocated randomly to two groups (intervention group = 65 and control group = 65).

During the intervention, 5 participants dropped from the intervention group (lost to follow-up = 3 and discontinued intervention = 2). In contrast, 35 participants dropped from control group (lost to follow-up = 21, hospitalized = 6, experienced stroke = 3, and withdrew from the study = 5). At the end of the study, there was an unequal sample distribution leading to losses. Approximately, 53.8% of participants in the control group dropped in this study, because participants felt very bored due to the monotonous behavior of the results of health education. Though they felt that they had many complaints about BP, but did not have enough access to the PHCs (Figure 2).

Table 1 shows from baseline data (n = 130), there were no statistically significant differences in the baseline characteristics of participant, SBP, and DBP in control and intervention groups (P > 0.050).

Table 2 shows that there were no significant differences in SBP and DBP pre- and post-test in the control group (P > 0.05). However, there were significant differences reducing SBP (130 mmHg vs. 90 mmHg; Z = −5.381) and DPB (90 mmHg vs. 80 mmHg; Z = −5.038) pre- and post-test combination of PMR and SE in the intervention group (P < 0.001).

Table 3 shows the comparison of number of type BP baseline and 3 months data in the control group (n = 30). There were significant differences baseline and 3 month data in control group for SBP (χ² = 60.0; P < 0.001) and DBP (χ² = 50.0; P < 0.001). The number of type SBP remained baseline and 3 month data. For type DBP, there were remained the number normal BP, although there were increased number of pre hypertension (6.7%) and reduced number of hypertension stage I (6.7%) from baseline and 3 month data.

Meanwhile, in intervention group (n = 60), the comparison of number of type BP baseline and 3 months data shows that there were significant differences baseline and 3 month data in intervention group for SBP (χ² = 54.13; P < 0.001) and DBP (χ² = 23.92; P = 0.001) as shown in Table 4. There was increased number of normal and pre hypertension for SBP and DBP (10% vs. 10%; and 20% vs. 31.6%), and reduced hypertension stage I for SBP and DBP (30% vs. 41.6%).

Table 5 shows the distribution of participants based on BP categories among dropout of participants in the control group (n = 35) and intervention group (n = 5). We observed the parameters of the majority of the control group: SBP with normal = 11.4%, pre hypertension = 51.4%, hypertension stage I = 37.1%; and all of DBP with normal; whereas the intervention group (SBP with pre hypertension = 80% and hypertension stage I = 20%; and all of DBP with normal).

This pilot study demonstrated effective improvement of BP among farmers using the combination of PMR and SE in agricultural health settings in Indonesia. After 3 months of follow-up, it is observed that the combination of PMR and SE significantly reduced SBP and DBP values in the intervention group compared with the control group. Therefore, the combination of PMR and SE is effective in reducing the SBP and DBP among farmers. The magnitude of reduction in BP was similar to those reported regarding the SE decreasing BP^5,26 and PMR reducing BP.¹⁷ These effects were clinically and statistically significant, as discussed below.

This study found that in the intervention group SBP and DBP were reduced among farmers after practicing the combination of PMR and SE. This is likely because, in the intervention group, the farmers learned and practiced SE movements as routine activities in the morning before going to work in the fields. After practicing SE optimally, it is possible for the body to relax more and the muscles may be ready for doing the main work,²⁷ so that the cardio-respiration of the body will get maintained and the daily pattern of BP is controlled.^26,28 Therefore, adequate training is needed for 15 min for the farmers before doing the core work in the agricultural fields.

SBP and DBP were reduced in the intervention group after practicing PMR for 3 months. This may be explained that PMR in 16 muscle groups, allows farmers to relax their muscles that have been used after working in the agricultural fields. Muscle relaxation provides an opportunity for muscles to be able to restore the situation by replacing damaged cells with new cells.²⁷ Thus, the process of using muscles is balanced with the recovery process of cell and muscle tissue, so that BP is controlled.^25,29 Therefore, PMR is needed for the farmer for 15 min before the farmers start to sleep, and getting adequate rest and adequate sleep will be able to support the maintenance of controlled BP.

This study identified that almost more than a half of participants in the control group dropped out in this study which reflected that no comparable number of participants left in the control group for the analysis. This indicated differential dropout that caused the results to be biased.³⁰ Therefore, researchers analyzed each one group pre- and post-test. The reasons for participant dropout in this study was the BP measurement indicating pre hypertension and hypertension stage I that caused participants in the control group to be hospitalized and experienced stroke. The 3 months of study in the control group reflected un-compliance with lost to follow-up and withdrawal. Non-compliance is generally a problem that arises in clinical intervention studies, which requires a long time period and is not reliable if all participants follow the clinical intervention.³¹ Therefore, researchers analyzed type BP baseline and 3 months data in control and intervention groups, separately. The main outcome in this study was BP, which was controlled in the subjects, here farmers, through a home visit to maintain PMR and SE program. If farmers were taking medication, researchers eliminated them from this study. Researchers were maintaining farmers so that they strictly follow the instruction of the study, although some participants-researchers were dropped due to problems in the part of the results. Researchers also used local PHNs as a third-person approach to monitor the adherence of PMR and SE practices by farmers who had training at the first-time meeting in this study.

Researchers knew factors that affected BP, including salt consumption, smoking, and medication adherence,³² family social support, depression, anxiety, and self-efficacy,³³ and physical activity.³⁴ However, in this study, researchers focused on SE as management for physical activity and PMR to reduce depression and anxiety among farmers. Therefore, researchers could maintain their BP. Then, in the study, researchers measured the main outcomes of the BP and researchers did not take the others tests and controlled the other variables. This is the community study and no other lab test could be conducted in rural areas of Indonesia which confirmed the results of previous studies that access to medicines facilitation³⁵ and social condition³⁶ are influencing factors in managing hypertension in rural areas of Indonesia.

The study found that the number of type BP of SBP and DPB were significantly different between baseline and 3 month data in the control and the intervention group. In particular, there was a decrease in the number of participants who experienced hypertension stage I in the intervention group. An overview of the results showed that SBP and DBP in the control group remained as such even after 3 months of follow-up. This requires an optimal health education in the farmer group, and it should be noted that regular BP checks at the PHCs will be able to measure the actual state of BP³⁷ leading to early identification of health problems in farmers. The health screening program can be done by integrating the health care system of farmers to rural areas to facilitate access to quality health services.

The combination of PMR and SE is effective in reducing BP among farmers. After 3 months follow-up of the data, the number of type SBP and DBP remained at baseline levels in the control group; while the number of SBP and DBP categories increased to normal and pre hypertension after 3 months of intervention. Therefore, a combination of PMR and SE could be implemented as an occupational health nursing program by PHNs in the farmer population. Furthermore, controlled compliance of participants in randomized controlled trails for clinical practice research should be done for reducing drop-out subjects in a community health setting research.

The implementation of a combination of PMR and SE in this study has several limitations. The PMR and SE practice program urgently requires compliance by farmers in carrying out regular and continuous training to maintaining their BP, although the number of participants who dropped out is high in this study. Therefore, scheduled supervision is needed from PHNs to increase the independence of farmers in conducting PMR and SE.

The method of measuring BP was performed by rounding off data and the results did not describe the true state of BP values. Measurements should be taken based on PHNs related to the operational standards of BP measurement procedures in PHCs. Then, for further research, matching of the subject in the control and intervention groups for randomized controlled trial study should be done and so a large number of samples are needed in the population of farmers with hypertension. Thus, the effectiveness of therapy can be assessed more objectively and can become a standard of therapy in the community.

Researchers used RCTs design. Therefore, samples are grouped randomly equal with the only difference being the intervention so to decide if the results are trustworthy. However, in this study, samples were later become unequal due to losses. Despite lost to follow-up, the study explained the losses with appropriate management using and analyzing 1-group pre- and post-test. Then, researchers conducted random assignment in groups at the appropriate level, however, unequal at the end. It is assumed that the study had an adequate sample size which was large enough to detect meaningful effects of the intervention as the study found that the intervention produced statistically significant effects.