S. Dassanayake1, G.T. Wilkins2, G. Sole1, M.A. Skinner1
1School of Physiotherapy, University of Otago, Dunedin, New Zealand, 2Dunedin School of Medicine, University of Otago, Department of Medicine, Dunedin, New Zealand

Background: Resistant hypertension (RHT), a phenotype of hypertension, cannot be effectively managed by medication alone. Aerobic and strengthening exercises are recommended as a cost-effective therapeutic modality to reduce blood pressure in hypertension. Although research is limited, exercise may also be effective in blood pressure management in RHT. Further, obstructive sleep apnoea (OSA), has a strong and close relationship with RHT but often remains undiagnosed.

Purpose: The purpose of this pragmatic clinical trial was to determine the effectiveness of a physiotherapist-supervised and homebased 12-week exercise programme on blood pressure in adults with RHT and OSA risk. The primary outcome measure was change in the magnitude of 24h ambulatory blood pressure (24hABP). Secondary outcomes were changes in 7-day activity levels, sleep, anthropometric parameters and quality of life.

Methods: The study comprised a single group pre-post-test clinical trial on a sample of adults 60 years and younger with RHT and OSA risk. Sample size was determined to detect a clinically significant 5mmHg difference in ambulatory blood pressure (significance level 5%, 80% power). The Wilcoxon ranked test was used for pre-post comparison of results.

Results: Fifteen adults (mean age 53.64±9.65y, n=7 male) with RHT and OSA risk consented. Mean anthropometrics were high: BMI 34.13±4.40 kg/m2; waist circumference male 109.07±10.89cm, female 111.62±15.27cm; neck circumference male 42.77±2.67cm, female 38.70±1.43cm. Eleven participants completed the study; 7/11 were included in statistical analysis for change in 24h blood pressure as 4/11 participants had medications changed between baseline and endpoint measurements. Pre-test mean systolic 24hABP was 149.86±15.75mmHg and post-test 143.43±7.50mmHg (z=-1.36, p=0.173), while pre-test diastolic was 85.29±11.43mmHg and post-test 81.28±5.65mmHg (z= -0.742, p=0.458). Mean pretest daytime systolic 24hABP was 153.28±16.74mmHg and 146.07.63mmHg post-test (z=-1.18, p=0.237); mean diastolic daytime ABP pre-test was 88.14±11.45mmHg and post-test 85.14±6.41mmHg (z=-0.738, p=0.416). Night-time systolic ABP pre and post-test were 133.86±19.18mmHg and 137.28±10.06mmHg (z=-1.19, p=0.233) respectively, while nighttime diastolic ABPs were 76.00±12.41mmHg and 74.14±5.76mmHg (z=-0.68, p=0.498). There was a clinically superior reduction in ambulatory blood pressure though differences were not statistically significant. The 7-day activity levels, sleep and anthropometric parameters also showed positive, but non-significant trends.

Conclusion(s): A negative trend was identified with clinically superior mean differences in blood pressure in response to a 12-week aerobic and strengthening exercise programme. Results suggest exercise be considered as a therapeutic modality to assist in blood pressure control in RHT. Exercise was also associated with improved sleep parameters and had a positive influence on anthropometric parameters, both of which are predisposing factors for hypertension. A fully powered randomised controlled trial is recommended for future research.

Implications: This research supports the role of the physiotherapist in contributing to management of blood pressure, including blood pressure resistant to medication and in those with RHT and OSA. The therapeutic effects of blood pressure reduction through physical activity should be an integral part of physiotherapy education at entry-level and in practice. The importance of managing blood pressure through exercise, a non-pharmacological and non-surgical intervention, demands further exploration.

Funding, acknowledgements: University of Otago PhD scholarship and School of Physiotherapy Research Fund

Keywords: Cardiorespiratory conditions, Hypertension, Exercise

Topic: Cardiorespiratory

Did this work require ethics approval? Yes
Institution: Ministry of Health, New Zealand
Committee: Health and Disability Ethics Commitee
Ethics number: 18/CEN/257

All authors, affiliations and abstracts have been published as submitted.

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