Kesan latihan senaman aerobik terhadap parameter kardiovaskular, fungsi endotelium dan kerosakan DNA di kalangan wanita prahipertensi dan hipertensi

Abstract

In Malaysia, the prevalence of hypertension is high. Hypertension is closely related to endothelial function and oxidative stress. The risk of hypertension is higher among women after 50 years of age. Aerobic exercise has been recognized as a useful intervention in the treatment of hypertension. This study was done to determine the effects of regular aerobic exercise on cardiovascular parameters, endothelial function and DNA damage in prehypertensive and hypertensive women before commencement of medication. Thirteen women aged 35 to 60 years old were recruited and underwent blood pressure (BP) measurement at rest and during a 24 hour period (24-H ABPM), blood tests for determination of lipid profile and glucose, urine test for measurement of 8-hydroxy-2’-deoxyguanosine (8-OHdG) as an indicator of oxidative stress, aerobic capacity test, body composition and ultrasound Flow Mediated Dilation (FMD). The exercise group (n=6) performed treadmill exercise three times per week at 30 minutes per session at 50 % of heart rate reserve (HRR) for four weeks, which was then increased to 70 % HRR and 45 minutes for another four weeks. The control group (n=7) continued with their usual routine. After four weeks, there was a significant reduction in resting systolic BP in both groups (P<0.05). As regards the resting heart rate (HR), submaximal exercise HR and exercise systolic BP, there were significant reduction in the exercise group (-4.00 bpm, -6.00 bpm, -17.00 mmHg, P<0.05) while the control group had an increment (+3.00 bpm, +3.57 bpm, +4.29 mmHg, P>0.05) respectively. After eight weeks, both groups had significant reduction in maximal exercise HR and systolic BP, with the exercise group achieving it at a higher exercise intensity (6.05 + 1.37 METs vs. 4.84 + 0.65 METs). In addition, there was a significant reduction in urine 8-OHdG in the exercise group (before intervention= 6.58 + 2.26, post intervention= 4.33 + 0.79 ng/mg creatinine, P=0.04). The exercise group also maintained their aerobic fitness and had significant increment in exercise time (before intervention= 13.29 + 0.96, post intervenstion= 14.67 + 2.23 minute, P=0.01). This study found that aerobic exercise at moderate intensity three times per week with 30 to 45 minutes every session reduced systolic BP and HR during exercise, decreased oxidative stress and maintained aerobic fitness in prehypertensive and hypertensive women who were not on medication.