European Journal of Cardiovascular Medicine

BMI is used for prediction of risk factor clustering among children and adolescents. It has significant clinical utility with respect to diagnosis and prognosis of various diseases. Overweight and obesity are associated with a number of diseases such as hypertension, cardiovascular diseases (CVDs), diabetes, endocrinal disorders.[1] The prevalence of overweight and obesity among children and adolescents aged 5–19 years has risen dramatically from just 8% in year 1990 to 20% in 2022. The rise has occurred similarly among both the boys and girls, in 2022 19% of girls and 21% of boys were overweight.[1] Among the various anthropometric indices BMI is found to be significantly correlated with RPP especially among young adults. Earlier arterial blood gas analysis was done to determine myocardial oxygen consumption (MVO2max), which is invasive, time consuming and tedious procedure.[2] RPP is a reliable indicator which determines myocardial oxygen consumption and work load in any condition. It is used in determining MVO2 max as it is simple and reliable process for calculation.[3] RPP is the product of SBP and HR, as both are indicators of coronary artery disease.[4] RPP is an easy and fairly reliable method to assess myocardial workload in resting state less than 100 is considered normal and above this implies an individual to cardiovascular risk.[5] Young adults are future of the society and their good health is the need of a good nation. Therefore, this study was designed to determine the correlation between body mass index and rate pressure product (RPP) among young adults so that necessary preventive measures can be taken to avoid further health hazards.

This cross-sectional study was conducted in Department of Physiology VIMSAR, Burla between Jan to March 2024.  We recruited 100 study participants, which included 66 males and 34 females. The study protocol was approved by Veer Surendra Sai Institute of Research and Ethics Committee; vide no 270-2022/I-S-O/001/dt 02.01.2024. This study followed the guidelines of Helsinki Declaration 1975, as revised in 2013. Written consent was taken from each subject. Simple random sampling method was applied for selection of study participants. For recruitment of study participants, we screened 114 college students from different general colleges of this locality. Among them 4 did not agree to participate and 10 were excluded on the basis of exclusion criteria and finally we selected 100 study participants. For selection of study participants’ healthy young adults between the ages 20 to 24 years were selected. Students suffering from coronary artery disease, kidney disease, endocrine disorders and on drug therapy were excluded from the study. Each study participant was clearly explained the study protocol and the procedure of recording of study variables. The height and weight were measured according to WHO protocol. Height was measured using a wall mounted measuring tape and the measurement was expressed in meter. During the measurement of height, the participants were instructed to stand erect, bare foot; both the arms were on two sides of body and foot touched to the wall. Weight was measured using a weighing machine standardized with a known 10 kg weight. They were instructed to have light clothing and bare foot while recording the body weight. BMI was calculated using Quit let index (BMI = weight in Kg / height in m2).The subjects were instructed to take 5 min rest before recording of heart rate (HR) and SBP. SBP was measured by mercury sphygmomanometer in sitting posture. Radial artery was palpated after 1 min and the pulse rate was taken as resting heart rate. Rate pressure product was derived by the designed formula RPP = SBP×HR×10-2.[6] Data was entered in Microsoft Excel. Statistical analysis was done by statistical software SPSS 20. Pearson correlation and unpaired t test were used for analysis of data. Microsoft word and excel used to produce tables and graphs.

Fig 1 depicts distribution of subjects on gender basis. Total no of subjects was 100 which included 66 males and 34 females.

Table 1 depicts age and anthropometric parameters. The mean age among males and females was 19.6±1.3 and 19.4±1 years respectively and the variation was not significant (p=0.426). The mean height among males and females was 167±7.5 and 156±8.1 cm respectively and the variation was significant (p=0.000). The mean weight among males and females was 67.8±13.5 and 54±9.2 Kg respectively and the variation was significant (p=0.000). The mean BMI among males and females was 24.2±4.5 and 22±3.3 respectively and the variation was significant (p=0.020).

Tab 1: - Age and anthropometric parameters

BMI-Body mass index, SD-standard deviation

Table 2 depicts hemodynamic parameters. The mean SBP among males and females was 128±10 and 115±9 mm hg respectively and the variation was significant (p=0.000). The mean HR among males and females was 81±13 and 98±13 beats per min respectively and the variation was significant (p=0.000).The mean RPP among males and females was 103±20 and 112±18 respectively and the variation was significant (p=0.034)

Tab 2: -Hemodynamic parameters

SBP- Systolic blood pressure, HR-heart rate, RPP-rate pressure product.

p<0.05 was considered to be significant.

Fig 2 depicts the correlation between BMI and SBP which showed a positive correlation (r=0.5310) between BMI and SBP significantly (p=0.032).

Fig 3 depicts the correlation between BMI and HR which showed a positive correlation (r=0.443) between BMI and HR significantly (p=0.001).

Fig 4 depicts the correlation between BMI and RPP which showed a positive correlation (r=0.512) between BMI and RPP significantly (p=0.002).

In the present study there was a positive correlation between BMI - SBP, BMI vs HR and BMI vs RPP. The difference is possibly due to sympathetic tone between underweight and overweight subjects.[7] A Danish study which included 276835 school children from 7 to 13 years of age found there was a significant linear association between obesity and the incidence of coronary artery events in adulthood.[8] Ravishankar P et al results states that systolic blood pressure  is linearly related to BMI in underweight and overweight males and overweight females.[9] In children and young adults obesity has been found to be associated with a higher prevalence of cardiovascular risk factors including hyperglycemia, hypertension, hyperlipidemia.[9] High BMI  play an important role in the pathogenesis of autonomic dysfunction. Adipose tissue in excess may cause accumulation of lipids in non-adipose tissue and may cause cardiac dysfunction through lipotoxicity.[10] The positive correlation between RPP with BMI indicated that cardiovascular risk increases withincrease in anthropometric indices especially BMI. RPP is considered as an index for MVO2 as well as one vital indicator of functional status of ventricles. Determination of MVO2 is considered to monitor the level of exercise to be practicedby various groups of people like obese persons, CVD individuals, diabetic patients as well as in normal health-conscious individuals including athletes.[11] Exercise is good for health but it should be standardized and done in limits otherwise creates health hazards. Different researches suggested that work of cardiac muscle beyond limits may lead to the occurrence of angina. RPP estimation is utilized to determine the limits of exercise.[12] The RPP in resting conditions varies between 70 and 90 in healthy adults is safe for good health. The RPP more than cutoff 100 is a potent risk factor for of cardiovascular health. [13,14]

This study revealed that RPP can be considered as an index of sufficiency of coronary perfusion. This central role of RPP in cardiac physiology is used in non-invasive quantification of MVO2 which is crucially important in both cardiovascular investigation and clinical cardiology. This study highlights the importance of managing and preventing obesity in youth as they are at higher risk of developing premature coronary artery disease

Funding – Nil

Conflicts of interest – No conflicts of interest

Acknowledgement: Authors are thankful to the staffs of Department of Physiology, VIMSAR, Burla, for their support to accomplish this work.

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