Can isometric resistance training safely reduce high blood pressure?


Date:
August 20, 2021
Source:
University of New South Wales
Summary:
This very accessible and easy to perform intervention could have
a strong effect on reducing blood pressure, say researchers.



FULL STORY ==========================================================================
When was the last time you had your blood pressure checked? High blood
pressure affects 1.13 billion people around the globe and in 2019,
it accounted for 10.8 million deaths. Worldwide, it's the leading risk
factor for mortality. More than a third of the Australian population
over the age of 18 has high blood pressure, yet it's estimated 50 per
cent of Australians don't realise they're living with it.


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As high blood pressure puts you at high risk of having a heart attack
or stroke (cardiovascular disease), it's important to keep track of your
blood pressure.

People over the age of 18 are advised to have a blood pressure check at
least every two years.

Given the impact of this global health challenge, there is a clear
need for strategies to reduce the prevalence and severity of high blood pressure, and exercise is one such strategy. While aerobic and dynamic resistance exercise appear effective at reducing blood pressure, a new
study led by UNSW Medicine & Health researchers has revealed isometric resistance training (IRT) as an emerging mode of exercise demonstrating effectiveness in reducing office blood pressure. Office blood pressure
refers to your pressure when taken during a GP visit, for example. It
is taken at one time-period, usually when you're sitting down.

What is isometric resistance training? IRT is a type of strength
training. During IRT, the muscles produce force but do not change
length. For example, pushing against a wall or holding a 'plank'.

This is different to more traditional strength training like a squat or
a push up or where muscles shorten and lengthen during the movement.

Currently, IRT is not recommended by several international guidelines for
the management of high blood pressure. This was mostly due to concerns
over its safety because the static nature of IRT causes blood pressure to increase markedly during exercise, particularly when performed using large muscle groups or at high intensity, compared to traditional strength
exercise such as lifting weights or aerobic exercise such as walking
or cycling.



========================================================================== However, lead authors of the study Mr Harrison Hansford and Dr Matthew
Jones, both accredited exercise physiologists at the School of Health
Sciences said their research showed IRT to be safe.

"We were interested in how IRT reduced blood pressure in people with high
blood pressure. We also wanted to know whether IRT was safe. We found
that IRT was very safe and caused meaningful changes in blood pressure -- almost as much as what you'd expect to see with blood pressure lowering medications," explained Dr Jones.

He said exercise is important for the management of high blood pressure,
but the researchers acknowledged many Australians were physically
inactive, with 'lack of time' commonly cited as a reason.

"IRT is a time-efficient means of reducing blood pressure, needing only
12 minutes a day, two to three days per week to produce the effects we
found in our review." "While the studies included in our review normally
used a specialised handgrip device, it's possible we would see the same
effects simply by asking participants to make a fist and squeeze it at
a certain intensity for the prescribed amount of time. This means IRT
could easily be performed while participants are sitting down watching
TV," said Dr Jones.



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"We also found IRT caused improvements in other measures of blood
pressure including central blood pressure (the pressure in the heart's
largest artery - - the aorta, and an important predictor of cardiovascular disease) and to a lesser extent ambulatory blood pressure (average blood pressure across a 24- hour period), neither of which had previously been reviewed." Although previous studies had shown IRT as being effective
for lowering office blood pressure, the studies had not comprehensively examined the safety of IRT.

IRT is accessible and easy to perform Dr Jones said IRT is a very
accessible and easy to perform intervention. He highlighted how exciting
it was to know such a simple intervention could have such a strong effect
on reducing blood pressure -- the leading risk factor for mortality,
globally.

"It's particularly exciting for people who may have difficulty performing
more 'traditional' exercise such as walking, cycling or strength
training knowing they have another exercise type in their toolkit to
help manage their high blood pressure." Dr Jones noted the research
team were surprised there were not increased risks of adverse events in
older adults.

"In fact, there were actually lower rates of adverse events in older
adults, making it a very appealing mode of exercise, especially in those
with mobility restrictions who may not be able to do other exercises
like aerobic or dynamic resistance training." Dr Jones acknowledged
research limitations in terms of the studies included in the scientific literature review, which were not always of 'high quality'. This means
the research team cannot be entirely confident in their results. Dr
Jones also acknowledged relatively few studies examined lower body IRT,
or IRT using different doses and intensities. Therefore, it is still
unclear how different types and doses of IRT may affect results, and
whether these would also be safe.

"There is a clear need for a large, high-quality randomised
controlled trials to better assess the effect of IRT on blood
pressure. To conduct such a study would be a clear goal for the
future. It would also be useful to study how different types
and doses of IRT affect results, and whether this differs between
males and females, so this would also be a goal of future research." ========================================================================== Story Source: Materials provided by
University_of_New_South_Wales. Original written by Emi Berry. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Harrison J. Hansford, Belinda J. Parmenter, Kelly A. McLeod,
Michael A.

Wewege, Neil A. Smart, Aletta E. Schutte, Matthew D. Jones. The
effectiveness and safety of isometric resistance training
for adults with high blood pressure: a systematic review
and meta-analysis. Hypertension Research, 2021; DOI:
10.1038/s41440-021-00720-3 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/08/210820111120.htm

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