Condition category
Circulatory System
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status

Plain English Summary

Background and study aims
High blood pressure affects many people in the UK. People with raised blood pressure (140-159/90-99 mmHg) are recommended to make changes in their lifestyle (e.g. smoking/alcohol/diet/exercise) and/or medication in order to reduce their blood pressure. Current knowledge suggests that a particular type of exercise - isometric exercise - can lower blood pressure. Isometric exercise involves holding a fixed body position for a short period of time. As most of the information about the benefits of this type of exercise comes from laboratory-based studies, researchers want to find out if it is possible for GP practices to offer NHS patients with clinically high blood pressure an isometric exercise plan to do at home and how it might affect their blood pressure over 6 months. They will also find out the experiences of those doing this type of exercise and whether it can be done consistently at home over time.

Who can participate?
Adults over the age of 18 with high blood pressure (systolic blood pressure of 140-159 mmHg)

What does the study involve?
Participants will be identified as potentially eligible by their GP surgery and invited to take part in the study. Upon consent, they will be asked to complete 5 days of home blood pressure monitoring followed by a screening appointment, involving checks of medical history and medication. They will also be asked to complete an isometric exercise ability test involving a 60-second wall squat to determine if they will be able to do the basic exercise. Once this is completed, participants will be randomly allocated to one of two groups. Those in the first group will be given standard care/lifestyle advice for raised blood pressure and asked to record their blood pressure for five days at weeks 4, 12 and 24. The second group will also be given standard care/lifestyle advice and prescribed an individualised isometric exercise programme. In order to prescribe this, the participant will be asked to visit their GP surgery to undertake a short isometric exercise test. They will then be asked to complete the isometric exercise training thrice weekly for 6 months, along with the blood pressure measurements at weeks 4, 12 and 24. Participants will also be asked to complete questionnaires at week 4, week 12 and week 24.

What are the possible benefits and risks of participating?
Participants in the isometric exercise group may benefit from improvements in leg strength and fitness over the training period which could benefit long-term health. They may also experience a reduction in blood pressure. After 6 months the control participants will also get an opportunity to complete the isometric exercise training.
Participants may take a while to get used to doing the exercise and may initially feel unbalanced whilst doing the isometric wall squats. Participants may experience a burning sensation in their legs as well as their body temperature increasing and heart beating faster. This is the body’s normal reaction to performing the exercise and should lessen as participants get used to the exercise plan. Following the exercise sessions, participants may experience slight muscle aching in the following 48-hour period during the early points of the exercise training plan. This would be a perfectly normal response to the exercise and should have no long-lasting effects. Blood pressure and heart rate increase during isometric exercise, but there is currently no evidence to suggest that this presents any risk to individuals with already elevated blood pressure. The risks of sudden heart problems (like a heart attack) during or after doing isometric exercise are very low. Participants will receive a phone call after the first week of exercise to check they are happy with their exercise plan and to collect heart rate and blood pressure data from the first week to check they are exercising at the right level of difficulty. Participants will be asked to inform the researchers straight away if they experience any problems whilst participating in the study. If the study team are concerned about a participants safety from the information collected throughout the study their GP will be informed. Provisions have been made for reducing the risk of contracting COVID-19. These include minimising the number of visits to the participants GP surgery (either 0 or 1) and if/when participants have to visit, the necessary personal protective equipment will be worn by the research staff with any social distancing procedures in place at the surgery being followed.

Where is the study run from?
Canterbury Christ Church University (UK)

When is the study starting and how long is it expected to run for?
April 2019 to December 2021

Who is funding the study?
National Institute for Health Research (NIHR) (UK)

Who is the main contact?
Dr Jonathan Wiles

Trial website

Contact information



Primary contact

Dr Jonathan Wiles


Contact details

Canterbury Christ Church University
North Holmes Road
United Kingdom
+44 (0)1227 922209



Additional contact

Miss Ellie Santer


Contact details

Canterbury Christ Church University
North Holmes Road
United Kingdom
+44 (0)1227 923357

Additional identifiers

EudraCT number

Nil known number

Nil known

Protocol/serial number

IRAS 274676, CPMS 45195

Study information

Scientific title

Feasibility study to assess the delivery of a novel isometric exercise intervention for people with Stage 1 hypertension in the NHS



Study hypothesis

Isometric exercise can be successfully delivered to patients with Stage 1 hypertension in an NHS primary care setting.

Ethics approval

Approved 22/05/2020, London - Bromley Research Ethics Committee (Level 3, Block B, Whitefriars, Lewins Mead, Bristol, BS1 2NT, UK; +44 (0)207 104 8105, +44 (0)207 104 8063;, REC ref: 20/LO/0422

Study design

Multi-centre randomized controlled feasibility study

Primary study design


Secondary study design

Randomised controlled trial

Trial setting

GP practices

Trial type


Patient information sheet

Not available in web format, please use contact details to request a participant information sheet


Stage 1 hypertensive patients (defined as a clinic BP of 140-159/90-99 mmHg) who are not taking anti-hypertension medication


Participants will be randomized into two groups, the intervention arm and the control arm, in a 1:1 ratio using sealed envelope software. Both groups will receive standard care/lifestyle advice and have their blood pressure monitored at week 1, week 12 and week 24. In addition, the intervention arm will be prescribed 6 months of isometric exercise training (three sessions per week, comprised of 4 x 2-minute bouts with 2-minute recovery periods in-between). The isometric exercise group will also be asked to complete a questionnaire about their experience of the exercise training, at week 4 and there will be a focus group asking the participants about their experience of the training, at month 4 and month 8.

Intervention type



Drug names

Primary outcome measure

1. Feasibility of isometric exercise prescription assessed using qualitative data from healthcare professional focus groups at month 11/12 of the study
2. Feasibility of isometric exercise intervention and study assessed using qualitative data from participants at month 7 and 11 of the study
3. Variance of blood pressure changes from baseline using participant blood pressure data at week 4, months 3 and 6
4. Sample size for a definitive randomised controlled trial, calculated using evidence of effect on participant systolic blood pressure change at week 1, months 3 and 6

Secondary outcome measures

1. Fidelity of the isometric exercise prescription measured using prescription competency assessment data at month 3
2. Fidelity of the isometric exercise prescription measured using observation data from the first Incremental Isometric Exercise Test (IIET) delivered from month 3 to month 5
3. Fidelity of the isometric exercise prescription defined by participant heart rate data within HR reference intervals at Day 7-10
4. Short and medium-term adherence rates recorded as those adhering to isometric exercise intervention at week 4, month 3 and month 6
5. Recruitment and attrition rates from data collected at sites at month 10 and month 15
6. GPs and healthcare professionals’ attitudes to isometric exercise as a treatment option for patients, measured using remote focus groups and telephone interviews at month 11/12
7. Cost and cost-utility of the isometric exercise intervention using healthcare resource use data and quality-adjusted life years (QALYs) at month 15 (or last patient follow up)
8. Participant experiences of undertaking isometric exercise using participant isometric exercise experience surveys at week 4
9. Effect of COVID-19 on recruitment rates and participation using participant focus groups or telephone calls at month 7 and 11 of the study
10. Feasibility of using observed home blood pressure readings for remote blood pressure monitoring, using participant blood pressure data and observations from the measures at day 1, week 4, month 3 and month 6

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Aged 18 or over
2. Clinic systolic BP 140-159 mmHg
3. Able to provide informed consent

Participant type


Age group




Target number of participants


Participant exclusion criteria

1. Currently taking anti-hypertensive medication
2. White coat hypertension, as evidenced by averaged home systolic BP <135 mmHg
3. Inability to undertake study intervention (isometric exercise)
4. Previous history of any of the following:
4.1. Diabetes mellitus (Type 1 or type 2)
4.2. Ischaemic heart disease (myocardial infarction and/or coronary angina and/or coronary revascularization procedure)
4.3. Moderate or severe stenotic or regurgitant heart valve disease
4.4. Atrial or ventricular arrhythmia
4.5. Stroke or transient ischaemic attack
4.6. Aortic aneurysm and/or peripheral arterial disease
4.7. Uncorrected congenital or inherited heart condition
5. Estimated glomerular filtration rate <45 ml/min (calculated using CKD-EPI or MDRD formulae, and taking most recent documented results)
6. Documented left ventricular ejection fraction <45% and/or left ventricular hypertrophy (by either echocardiography or standard ECG criteria e.g. Sokolow-Lyon)
7. Documented urine albumin:creatinine ratio >3.5 mg/mmol
8. Inability to provide informed consent
9. If female, pregnancy or currently breastfeeding
10. Enrolled in another Clinical Trial of an Interventional Medicinal Product or Medical Device or another interventional study
11. Medical condition that, in the opinion of the investigator, would make the participant unsuitable for the study

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

Newton Place Surgery
Newton Road
ME13 8FH
United Kingdom

Trial participating centre

Northgate Medical Practice
1, Northgate
United Kingdom

Trial participating centre

Canterbury Medical Practice
Patrixbourne Road Bridge
United Kingdom

Sponsor information


East Kent Hospitals University NHS Foundation Trust

Sponsor details

Kennington Road
TN24 0LZ
United Kingdom
+44 (0)1233 633331

Sponsor type

Hospital/treatment centre



Funder type


Funder name

National Institute for Health Research

Alternative name(s)


Funding Body Type

government organisation

Funding Body Subtype

National government


United Kingdom

Results and Publications

Publication and dissemination plan

This research will lead to the following outputs: published guidelines for training and delivery of a home-based IE intervention for Stage 1 hypertensive patients in the NHS; data to inform sample size estimates for a substantive trial; a patented IE tool and copyrighted training manual for the IE intervention delivery; the identification of barriers and enablers for delivering this intervention in the NHS; and a funding application and protocol for a substantive randomised controlled trial in the NHS to establish effectiveness and mechanisms of IE action in reducing BP in this population.
The results of the study will be disseminated through local, national and social media. The researchers will present their results at national and international conferences (e.g. UKactive Summit) and publish findings in high-impact, open-access peer-reviewed journals in the field where the project team’s previous work has been well-received (e.g. Hypertension, Journal of Human Hypertension, Journal of Hypertension, Journal of Applied Physiology, PLOS Medicine, British Medical Journal).
Study participants will receive a personalised report of their own results and a summary of study findings will also be sent to GP practices and local organisations (E.g. CCCCG, EKHUFT, Kent and Medway STP, Kent AHSN and NIHR CRN:KSS). The study final report will be submitted and a lay summary disseminated to a wider audience to create national impact by engaging with policy and national governing body organisations (e.g., PHE, NICE, National Centre for Sport & Exercise Medicine), third sector organisations (e.g. BHF, BHS) with the aim of understanding the evidence required to influence current hypertension treatment guidelines with respect to offering lifestyle interventions like IE as standard care and a tangible product that can be marketed in the NHS.

IPD sharing statement
The datasets generated during and/or analysed during the current study are/will be available upon request from Dr Jonathan Wiles ( The data will become available 1 year after the study finishes which will be approximately December 2022 and may be accessed for up to 5 years. Anonymised data may be accessed by researchers at universities, NHS organisations or other healthcare providers where the sharing of data has a clearly defined purpose and its use will be of benefit to wider society. Data will be shared by secure data transfer. Consent from participants was obtained for the use of their information for future research and to be shared anonymously with other researchers.

Intention to publish date


Participant level data

Available on request

Basic results (scientific)

Publication list

Publication citations

Additional files

Editorial Notes

24/11/2020: The recruitment start date was changed from 01/11/2020 to 18/01/2021. 10/11/2020: Uploaded protocol (not peer reviewed) Version 3.2.1, 01 October 2020. 17/09/2020: Trial's existence confirmed by the Health Research Authority.