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Reprinted from Australian Family Physician Vol. 34, No. 6, June 2005 4 419
Approximately 29% of Australians have blood
pressure (BP) above the recommended level of <120
systolic and <80 diastolic. These individuals account for
8.6% of patient encounters and 7.9% of prescriptions
in general practice.
1
As the population ages, these
statistics will increase. Over 50% of adults aged 55–74
years already have BP outside the desirable range
(Table 1). An individual with normal BP at 55 years
of age has a 90% lifetime risk of developing high
BP.
2
Costs associated with drugs, pathology, radiology
and complications due to stroke, coronary heart
disease, kidney disease, heart failure, and end stage
renal disease
3
makes hypertension the third greatest
modifiable medical risk factor burden in Australia,
second only to tobacco smoking and physical inactivity.
4
For this reason, lifestyle modifying treatments, including
diet and physical activity, are first line interventions for
high BP management, even when drug therapy is
implemented.
5,6
There is little debate that exercise is as important
as pharmacologic inter vention for many medical
conditions.
7
Yet, while medical students spend years
learning about how to prescribe drugs, they are rarely
instructed on the value of the exercise prescription
for various medical conditions, or how to prescribe it.
8
The hypertension-exercise relationship
Epidemiologic studies suggest that the relationship
between sedentar y behaviour and hypertension
is so strong that the National Heart Foundation,
5
the World Health Organisation and International
Society of Hypertension,
9
the United States Joint
Nationa l Committee on Detection, Evaluation
and Treatment of High Blood Pressure,
6
and the
Exercise and
hypertension
BACKGROUND Exercise is advocated for the
prevention, treatment and control of hypertension.
However, the treatment effect of exercise on
hypertension is difficult to determine as many
studies are poorly controlled and involve small
sample sizes.
OBJECTIVE This article reviews current
knowledge about exercise and blood pressure
(BP), and provides a guideline for exercise
prescription that considers the health status and
age of the patient.
DISCUSSION An evidence based literature
analysis by the American College of Sports
Medicine indicates that an isolated exercise
session (acute effect) lowers BP an average of
5–7 mmHg. Depending upon the degree the
patient’s BP has been normalised by drug therapy,
regular aerobic exercise significantly reduces
BP the equivalent of 1 class of antihypertensive
medication (chronic effect). For most hypertensive
patients exercise is quite safe. Caution is required
for those over 50 years of age, and those with
established cardiovascular disease (CVD) (or
at high CVD risk) and in these patients, the
advice of a clinical exercise physiologist is
recommended.
Healthy heart
•
THEME
Tom Baster
MBChB, BSc, DipMSM,
is a general practitioner,
Brisbane, Queensland.
tbaster@bigpond.net.au
Christine Baster-Brooks,
PhD, CSCS, is a
kinesiologist specialising
in exercise prescription
for aging populations,
Brevard Community
College, USA.
420 3Reprinted from Australian Family Physician Vol. 34, No. 6, June 2005
Theme: Exercise and hypertension
American College of Sports Medicine (ACSM)
10
have
all recommended increased physical activity as a
first line inter vention for preventing and treating
patients with prehypertension (systolic BP 120–
139 mmHg and/or diastolic BP 80–89 mmHg). The
guidelines also recommend exercise as a treatment
strategy for patients with grade 1 (140–159/80–
90 mmHg), or grade 2 (160–179/100–109 mmHg)
hypertension (Table 2). Physical activity is particularly
appealing because it has favourable effects on other
cardiovascular disease (CVD) risk factors. It is a low
cost intervention with few adverse side effects if
undertaken according to recommended guidelines.
11
How much can exercise lower BP?
Th e 2004 AC SM review of evidenced based
literature on the BP-exercise relationship
11
suggests
the following important conclusions for the GP
to consider:
• A lifestyle of physical activity can reduce the risk of
developing hypertension. Inactive individuals have
a 30–50% greater risk than their more physically
active counterparts for developing high BP as they
age. Therefore, an active lifestyle has an important
preventive effect
• Two types of endurance exercise effects are
significant – acute effects and chronic effects
– acute effects: there is an average reduction in
BP of 5–7 mmHg immediately after an exercise
session. This is referred to as postexercise
hypotension (PEH). While PEH occurs in both
normotensive and hypertensive patients, a greater
PEH is seen in hypertensives. The PEH effects can
occur for up to 22 hours regardless of the exercise
intensity
– chronic effects: the average BP reduction with
regular endurance exercise for hypertensives
not normalised by drug therapy in the literature
review is 7.4 / 5 .8 mmHg. I f baselin e BP i s
normal because of drug therapy, the average
decrease was a n addition a l 2.6/1.8 m m H g
irrespective of drug therapy type. The studies
used a variety of endurance based programs
involving walking, jogging or cycling of moderate
intensity (30–90% of VO2 reserve) ranging from
4–52 weeks in length. Sessions typically lasted
30–60 minutes
• Overall, resistance training has a favourable chronic
effect on resting BP, but the magnitude of the BP
reductions are less than those reported for an
aerobic based exercise program.
12
As well, limited
evidence suggests that resistance exercise training
has little PEH effect.
These decreases in BP do not seem to be large,
but as the ACSM point out, a 2 mmHg reduction in
systolic and diastolic BP reduces the risk of stroke
Table 1. Australian population statistics for hypertension, cholesterol and overweight
20
Hypertensive (%) Total cholesterol of 5.5 mmol/L or more (%) Overweight (%)
Age group in years Men Women Men Women Men Women
25–34 7.1 3.4 32.2 31.2 61.1 35
35–54 21.6 14.9 58 46.5 68.1 51.5
55–74 58.5 55.8 58.3 72.5 74.1 67.8
75+ 78.8 74.6 49.3 65.4 63.6 52
Table 2. Definition and classification of BP levels (mmHg)
5
Category Systolic Diastolic Action
Normal <120 <80 Encourage lifestyle modification if sedentary
High normal* 120–139 80–89 Lifestyle modification
Grade 1 (mild) 140–159 90–99 Lifestyle modification
Grade 2 (moderate) 160–179 100–109 Lifestyle modification
Grade 3 (severe) ≥180 ≥110 Lifestyle modification
Isolated systolic hypertension ≥140 <90 Lifestyle modification
*High-normal has been labelled as prehypertension
6
Reprinted from Australian Family Physician Vol. 34, No. 6, June 2005 4 421
Theme: Exercise and hypertension
by 14% and 17%, and the risk of coronary artery
disease by 9% and 6% respectively. The Heart
Foundation’s Hypertension management guide for
doctors states that fewer than 50% of patients
treated for hypertension will achieve an optimal
response with a single antihypertensive medication,
and that in the majority of cases 2 or 3 agents
from different therapeutic classes will be required.
5
As an example of the effects of drug therapy on
hypertension, the product information for irbesartan
quotes mean decreases in BP (based on 7 major
placebo controlled 8–12 week studies in patients with
Table 3. How to prescribe exercise to hypertensive patients based on health status and age
21
Patient category
Exercise testing
and monitoring
Exercise type
Frequency
Intensity
Duration
Weight problems
Column A
• Prehypertensives with no
suspected CVD <50 years
• Grade 1 hypertensives <50
years
Not necessary
Aerobic activities: walking,
jogging, cycling, swimming
Resistance training for retaining
muscle mass
Monitoring not necessary, but
suggest they seek advice from a
clinical exercise physiologist for
a conditioning and aerobic based
training program
6–7 days/week
Start with 20–30 minutes
continuous aerobic activity at
comfortable pace (50–65%) of
maximum heart rate for 3–4
weeks for general conditioning
Then exercise at up to 85% of
maximum heart rate
Maintain an endurance based
resistance training for muscle
maintenance
Aim for 30–60 mins/day
(minimum 150 mins/week of
aerobic activity)
Column B
• Prehypertensives with
suspected CVD
• Prehypertensives >50 years
with no suspected CVD
• Grade 2 hypertensives with no
suspected CVD <50 years
Recommended
Walking, cycling until medically
evaluated
Send to clinical exercise
physiologist for conditioning and
aerobic training advice
Monitoring probably not
necessary unless patient has
been sedentary for a number of
years and feels uncomfortable
about exercise
Resistance training for muscle
maintenance
5–7 days/week
Work at light-moderate intensity
until evaluated and conditioned
Then undertake a maintenance
aerobic program at up to 85% of
maximum heart rate
Maintain an endurance based
resistance training for muscle
maintenance
Start with 20–30 mins/day of
continuous activity. Build to
30–60 mins/day
Column C
• Hypertensives with no
suspected CVD >50 years
• Hypertensives with suspected
CVD
Recommended
Low impact activities such as
walking, cycling, swimming
Resistance training for muscle
maintenance
Send to clinical exercise
physiologist for monitored
conditioning program
Follow aerobic training program
designed by a clinical exercise
physiologist. Periodic monitoring
may be necessary
5–7 days/week
Light-moderate. Lower intensity
can start with 20–30 mins/day of
continuous activity then build to
45–60 mins/day
Maintain an endurance based
resistance training for muscle
maintenance
Start with 20–30 mins/day of
continuous activity. Build to
30–60 mins/day (minimum 150
mins/week)
For patients who are overweight, emphasise weight reduction through diet modification. Goal is 60 mins/
day of aerobic exercise. Suggest alternating aerobic activity type to avoid injuries. Emphasise endurance
resistance training of 3 sets of 12–15 repetitions. Do not make resistance training main exercise. It is
important not to hold breath while lifting weights
422 3Reprinted from Australian Family Physician Vol. 34, No. 6, June 2005
Theme: Exercise and hypertension
a baseline diastolic BP of 95–110 mmHg) compared
to placebo after 6–12 weeks as:
• 7.5–9.9/4.6–6.2 mmHg for the 150 mg dose, and
• 7.9–12.6/5.2–7.0 mmHg for the 300 mg dose.
13
Why exercise has a reducing effect on BP
How physical activity positively affects BP is not known.
One theory is that physical activity improves endothelial
function. The endothelium lining of blood vessel walls
maintains normal vasomotor tone, enhances fluidity of
blood, and regulates vascular growth.
14
Abnormalities in
these functions contribute to many disease processes
including angina, myocardial infarction, coronar y
vasospasm, and hypertension.
Another theory proposes that exercise enhances
shear stress (a force acting parallel to blood vessels)
14
stimulating the production of nitric oxide (NO) by the
endothelium. In healthy blood vessels NO enhances
smooth muscle relaxation and maintains the blood
vessel in the normal resting state.
15
Small changes in
vessel diameter profoundly impacts vascular resistance.
There are also vascular structural changes such as
increased length, cross sectional area, and/or diameter
of existing arteries and veins in addition to new vessel
growth.
11
Endurance trained subjects, for example,
have larger arterial lumen diameter in conduit arteries
than untrained controls.
16
Aerobic based training also
appears to increase large artery compliance.
Table 4. Classification of physical activity
intensity based on physical activity lasting
up to 60 minutes
21
Intensity % maximum heart rate*
Very light <35
Light 35–54
Moderate 55–69
Hard 70–89
Very hard >90
Maximal 100
*Maximum heart rate can be estimated by 220–age
Figure 1. Flow chart for selecting a suitable exercise prescription for hypertensive patients
Is patient prehypertensive or hypertensive?
Prehypertensive
Suspected CVD
No Yes
<50 years
Yes No
Follow exercise
prescription
column A (Table 3)
Follow exercise
prescription
column B (Table 3)
Follow exercise
prescription
column C (Table 3)
Grade 1 and 2 hypertensive
Suspected CVD
No Yes
<50 years
Yes No
Follow exercise
prescription
column A
(Table 3)
Follow exercise
prescription
column C (Table 3)
Follow exercise
prescription
column C (Table 3)
Follow exercise
prescription
column B (Table 3)
Grade 2Grade 1
Reprinted from Australian Family Physician Vol. 34, No. 6, June 2005 4 423
Theme: Exercise and hypertension
According to ACSM,
11
physical activity may also
reduce the elevated sympathetic nerve activity that
is common in essential hypertension. The exact
mechanism for PEH remains unclear, but appears to
involve the arterial and cardiopulmonary baroreflexes.
Studies suggest that the operating point of the
arterial baroreflex is set to a lower BP after an acute
bout of exercise.
17
How to prescribe exercise
To determine the type of exercise you should
prescribe for hypertensive patients, use the flow
chart in Figure 1 and then consult the appropriate
column in Table 3. Your advice depends on the
patient’s age, BP and overall CVD risk. Based on
the literature review, ACSM recommends the
following guidelines.
Type of exercise
Rhythmical and aerobic exercise involving large
muscle groups is the preferred treatment strategy
(walki ng , running, cyclin g , sw imming) fo r all
hypertensive patients. Moderate intensity exercise
(50–65% of maximum heart rate) on most days
of the week for at least 30–60 minutes appears
optimal. A brisk walking pace is moderate; jogging or
running is vigorous. Resistance training can be
prescribed as an adjunct to aerobic activity as this
type of exercise helps maintain and build muscle
mass, especially in an aging bo dy. However,
resistance exercise should not serve as the primary
exercise program as it does not have the same
antihypertensive effects as aerobic exercise.
11
Assessment before commencing exercise
Most prehypertensive and grade 1 hypertensive
patients can safely begin a moderate intensity
exercise program w i t h o u t extensive medical
screening.
18
Patients with grade 2 hypertension
a n d n o s i g n s o f C V D m u s t h ave t h ei r BP
controlled before they begin an exercise program.
Patients with risk factors for CVD and patients over
50 years of age will benefit from a stress test to
determine how their heart responds to exercise.
An exercise systolic BP higher than 220 mmHg, or
diastolic BP higher than 100 mmHg is considered
abnormal. Some with treated hypertension may
a l so h ave a n ex a gg er a t e d B P r es po n s e t o
exer c is e t h at is as s oc i at e d w it h i n cr ea s ed
CVD risk. Such individuals requi r e a card i a c
eva l u at i o n f o l lo w e d b y a t r a i n i n g p r o g r a m
designed and monitored by a certified clinical
exercise physiologist.
Patie nts over 50 years of a ge w ill require
additio nal evaluation, as at least h alf will b e
over weight, and/or will have high cholesterol
(Table 1); 40–50% will have heart, stroke and/or
vascular conditions; and around 50% will have
led a sedentar y lifestyle and be at high risk for
CVD.
19
Theoretically these individuals should be
placed under medical super vision in dedicated
rehabilit ation centres where they can receive
education about exercise, and their physiological
r e ac ti o n s t o exer ci s e m o n it or e d u n t il th ey
have s o me m in i mu m l evel o f c o n di t io n in g .
However, dedicated rehabilitation centres are
generally only available in major cities. They are
also usually used for postcardiac event patients and
not readily accessible to other patient populations.
An alternative is to arrange for the patient to
have a stress test, or stress echo, and consult
with a cardiologist. After you have this information
send the pa tient to a gym where there is a
resident clinical exercise physiologist on staff for
education about their health condition and how
an exercise program can improve it. The clinical
exercise physiologist should also design an ongoing
aerobic based training program for the patient
to pu r s ue after achiev i n g a minim a l level of
conditioning. While formal education and base
conditioning is t aking place, most patients can
begin light-moderate exercise such as walking. Note
that beta blockers diminish the heart rate response
to exercise, therefore patients taking these agents
should use the perceived level of exertion (Table 4)
rather than target heart rate.
Conclusion
Although it can be difficult to motivate patients
to exercise regularly, the benefits of exercise
equate to th e effects of drug treatment and
should be vigorously encouraged. If the exercise
program is designed correctly, it is quite safe for
most hypertensive patients and also has other
important health benefits relevant to their CVD
risk factors. It is therefore important to prescribe
exercise for patients who have hypertension, or
are at risk of getting hypertension, with the
same consideration as prescribing any oth er
effective treatment.
424 3Reprinted from Australian Family Physician Vol. 34, No. 6, June 2005
Theme: Exercise and hypertension
Summary of important points
• Aerobic exercise plays an important role in
BP control, and patients should be vigorously
encouraged to exercise.
• Blood pressure drops of about 5–7 mmHg can be
obtained with exercise which may reduce the need
for medication.
• Exercise is a low cost option and also has other
significant health benefits.
• For most hypertensive patients, exercise is quite safe
but caution is required for those with identified cardiac
risk factors. A clinical exercise physiologist can help
educate these patients about their health condition
and prescribe a program of suitable exercise.
Resource
For help in finding a certified exercise clinical physiologist
visit the Australian Association for Exercise and Sport
Science website at: www.aaess.com.au
Conflict of interest: none declared.
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AFP