Effect of Bmi and Level of Physical Activity on Blood Pressure and Heart Rate

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Table 7: Outcomes of analysis of covariance

Variable

PGender

PBMI

PGender*BMI

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Systolic Arterial Pressure

0.06

0.98

Diastolic Arterial Pressure

0.35

0.42

Mean Arterial Pressure

0.14

0.59

Heart Rate

0.005

0.55

0.01

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Variable

PActivity

PBMI

PActivity*BMI

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Systolic Arterial Pressure

0.89

0.79

Diastolic Arterial Pressure

0.72

0.81

Mean Arterial Pressure

0.98

1.0

Heart Rate

0.11

0.43

0.37

Values ≤ 0.05 are bolded.

Data are from a total of 598 participants. The P-Values on the other hand determines the significance of the data. P-values that are ≤ 0.05 suggest evidence against the null hypothesis (i.e. no statistical significance between the variables). As such, age, height, weight and BMI all have P-values less than 0.05. Therefore, it is indicative that these variables are factors that may influence blood pressure and heart rate.

Table 5: Characteristics of participants according to their usual level of physical activity.[pic 10]

Data are from a total of 598 participants. P values are the outcomes of one-way analysis of variance. *P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001 for post hoc comparisons with ‘no exercise’ (Dunnett’s test). TPW = times per week, SD = standard deviation, BMI = body mass index.

The post hoc comparison using a Dunnett’s test allows for comparisons between one control treatment (no exercise) and each of experimental treatments (amount of exercise per week). P values for, weight and BMI are both

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Figure 6 Relationships between body mass index and arterial pressure and heart rate according to usual level of physical activity.

[pic 11]

Individuals who do not participate in regular exercise (blue, n = 94), 1-2 times per week (green, n = 212), 2-5 times per week (red, n = 195) and more than 5 times per week (pink, n = 88). For other variables no significant effects of usual level of activity were detected, so the line of best fit for the combined data is shown. Individuals whom partake in exercise five times per week were distributed in a central manner. However, mean arterial pressure was on average higher in comparison to the other experimental groups. In contrast, individuals who exercise did minimal exercise and 1-2 times per week showed a scattered distribution.

DISCUSSION:

This study aimed to investigate the influence of level of activity and body mass index upon the The relationship between body mass index and hemodynamic function was explored whilst conducting this study. Evident with the above results, BMI is one of many factors that can account for the fluctuations observed in blood pressure and heart rate.

P-Values derived from this Dunnett’s’ test for both weight and BMI were found to be Zachariah et al. obese or individuals with higher BMIs, tend to have increased blood volume and larger stroke volume (amount of blood pumped out of the heart via the left ventricle to the rest of the body during each contraction) (Zachariah et al., 2014). Therefore, as BMI and weight increase, systolic pressure (force exerted upon the arteries as during contraction to push blood throughout the rest of the body) will also increase. This is most likely due to larger (obese) individuals needing remodel the diameter of the arteries in order to compensate for the higher ambient flow (Lakatta et al., 2009). Furthermore, an increase in systolic blood pressure is often associated with a decrease in diastolic blood pressure (Licata et al., 1994) which was highlighted with a P-value of 0.03 (Table 5) . However, such relationship is often associated relative risks of cardiovascular mortality (Jahrling et al., 1980). Therefore, subjects whom fall under these categories should seek further testing to minimalize possible risks.

Furthermore, heart rate demonstrated an overall decrease as the level of exercise (times per week) increased; reducing from a mean of 79.6 (beats/min) to 71.8 (beats/min) from no exercise to five times per week, respectively. This trend was supported by the pattern seen in figure 6 where individuals undertaking exercise >5 times per week were having a lower heat rate in comparison to the other groups. A such, allowing the heart's left ventricle more e time to fill with blood and thereby deliver oxygen and nutrients to the body as necessary (Chandramohan et al., 2012).

It was expected that physical activity would have an impact on the relationship between body mass index and the hemodynamic variables, including; mean arterial pressure, heart rate, systolic arterial pressure and diastolic