Exercise and Blood Pressure: The Role of the Fitness Instructor
Everyone seems to have it, but what exactly is high blood pressure? Blood
pressure is the force in the arteries when the heart beats (systolic pressure)
and when the heart is at rest (diastolic pressure). It's measured in millimeters
of mercury (mm Hg). High blood pressure (or hypertension) is defined in an
adult as a blood pressure greater than or equal to 140 mm Hg systolic pressure
or greater than or equal to 90 mm Hg diastolic pressure.
High blood pressure directly increases the risk of coronary heart disease
(which leads to heart attack) and stroke, especially when it's present with
other risk factors.
Table A. Classifying Blood Pressure
If Your Blood Pressure Values Are: You Have:*
Systolic ** Diastolic **
Less than 130 and Less than 85 Normal blood pressure
130-139 or 85-89 High-normal blood pressure
140-159 or 90-99 Stage 1 (mild) hypertension
160-179 or 100-109 Stage 2 (moderate) hypertension
180-209 or 110-119 Stage 3 (severe) hypertension
210 or higher or 120 or higher Stage 4 (very severe) hypertension
--------------------------------------------------------------------------------
Source: Report of the Joint National Committee on Detection, Evaluation,
and Treatment of High Blood Pressure, Bethesda, MD, National Heart, Lung,
and Blood Institute, National High Blood Pressure Program, 1993
* If your systolic and diastolic blood pressures are at different levels,
the higher level is your blood pressure class.
** Systolic blood pressure is the top, or first, number; diastolic is the
bottom, or second, number.
One of the central and most specialized roles of a fitness instructor, is
that of exercise prescription. Individual clients will have specific goals
and needs that must be catered for in order to design the optimal programme
of exercise. In spite of this specificity, most individuals can be categorized
into one of a number of general populations. A number of medical considerations
will have to be taken into account or even be central to programme design;
one of the most common will no doubt be hypertension. Hypertension is present
in epidemic proportions within industrialized societies and is linked to many
cardiovascular pathologies. There remains much debate over the merits of aggressive
pharmological therapy in the treatment of individuals with mild to moderate
elevations in blood pressure. There is however, no such debate over the efficacy
of aerobic exercise as a treatment.
Research suggests that aerobic/endurance exercise is most beneficial for hypertensive
populations. Endurance exercise training will elicit an average reduction
of 10mmhg for both systolic and diastolic blood pressures in individuals with
mild hypertension (ACSM, 2000). As a fitness instructor the mode, frequency,
duration and intensity of exercise need to be evaluated. It is recommended
by the ACSM that endurance training at 50-85% of maximum oxygen uptake is
undertaken for 20-60 minutes 3-5 days per week. It should also be emphasised
to the client that physically active and aerobically fit hypertensive individuals
have markedly reduced mortality rates in comparison to there sedentary hypertensive
peers. This is due to the fact that endurance exercise has a beneficial effect
upon the cardiovascular system that interacts with other CVD risk factors.
The danger that is associated with the adoption of an exercise programme,
is the higher blood pressure induced by exercise. It is thought that hypertensive
individuals are at greater risk of sudden cardiac death. Although there is
limited evidence to support this notion, it remains prudent to recommend lower
intensity exercise (<85% max oxygen uptake). Resistance training can still
be prescribed, but high repetitions should be prescribed and perhaps a circuit
of exercises should be encouraged rather than a standard sets and repetitions
protocol. Another consideration is the interaction between exercise and medication.
Although most anti hypertensive drugs will generally reduce the absolute level
of blood pressure that is experienced during exercise and also the heart rate
response. This is a crucial consideration when setting the intensity of exercise
on different exercise equipment. Beta blockers are thought to reduce absolute
exercise tolerance and the exercise induced rise in HDL cholesterol. It is
therefore suggested that angiotensin-converting enzyme inhibitors. Calcium
channel blockers, and alpha-blockers are especially well suited for persons
with uncomplicated essential hypertension and physically active lifestyles.
The adoption of a physically active lifestyle is itself something that must
be emphasised and promoted. Research that have investigated the effect of
exercise on blood pressure and stop training, indicate that their blood pressure
returns to initial pre-exercise values following a sustained period of detraining.
The blood pressure lowering effect of exercise training is evident only as
long as a regular training programme is maintained. This should be outlined
to clients, once a regular pattern of physical activity had been adopted.
Other important considerations for hypertensive individuals, as mentioned
earlier, is the possibility that endurance exercise training may elicit other
health benefits in addition to lowering of blood pressure. The incidence of
other modifiable CAD risk factors, including obesity, abnormal lipid profiles,
insulin resistance, and glucose intolerance, is also more prevalent in hypertensive
individuals.
Endurance exercise training, in addition to reducing blood pressure in hypertensive
individuals, also improves glucose intolerance and insulin resistance, obesity
and caloric balance and lipid profiles in relatively healthy individuals.
Hopefully the previous information has given a brief overview of exercise
and hypertension and in addition to a knowledge of exercise types and programme
design, should provide enough information to construct exercise programmes
that provide major physical and mental health benefits to your clients. The
following is a brief summary of the special considerations that you may wish
to take into consideration during the construction of a programme of exercise
for an individual with hypertension:
· The type, frequency and duration of activity are important. People
with hypertension should exercise daily for 30 minutes or more at a moderate
level to gain health benefits.
· People using medications, such as beta-blockers, should be cautious
of developing heat illness when exercising. These medications and diuretics
impair the ability to regulate body temperature.
· Adults with hypertension should extend the cool-down period of the
workout. Antihypertensives, such as alpha blockers, calcium channel blockers,
and vasodilators may cause BP to lower too much after abruptly ending exercise.
· Overweight and obese adults with hypertension should combine regular
exercise and weight loss to effectively lower resting BP.
· Promoting the BP-lowering effects of single exercise sessions may
best motivate people to exercise. Physicians are encouraged to promote the
role of exercise in controlling BP to their patients.
· A physician evaluation and clearance is necessary for those with
severe or uncontrolled BP prior to beginning an exercise program. Higher risk
patients (such as those with coronary artery disease or chronic heart failure)
should lessen the intensity of their training program.
In addition to exercise prescription however, it would be thoughtful to provide
a client with additional lifestyle guidelines. Perhaps an information sheet
containing the following points would be prudent:
· Maintain a healthy weight.
· Exercise on a regular basis.
· Reduce sodium to 2.3 grams or less each day.
· Avoid appetite suppressants, decongestants, and nonsteroidal anti-inflammatory
medications.
· Reduce stress by learning relaxation techniques.
· Reduce dietary fat and cholesterol.
· Limit alcohol consumption to less than one ounce daily.
· Stop smoking.
Motivation is key in the fitness industry, and information such as that contained
within this article is essential for reinforcing any desire a client or potential
client has to adopt an exercise programme. In addition, if staff appear knowledgeable
and caring it will further reinforce the incentive to exercise.
