This week’s fitness blog covers guidelines for fitness instructors when they are taking a client’s blood pressure.
When a gym instructor first meets a client, they’ll ask questions about their goals, lifestyle, medication and other information that could impact on their training. They will also assess the client’s health and fitness by taking a blood pressure reading. Too high blood pressure can be a precursor to conditions such as coronary heart disease.
Both systolic and diastolic blood pressure will be measured and most personal trainers nowadays will use an automated blood pressure monitor rather than the traditional aneroid sphygmometer plus stethoscope method.
Systolic blood pressure
Systolic blood pressure is the pressure against the arterial walls when the left ventricle of the heart contracts. If this is too high the result is pressure on the heart. As any personal trainer will know, if a muscle comes under prolonged pressure, it will fatigue and potentially fail to complete its function. For the heart muscle, this will clearly have serious implications.
Diastolic blood pressure
Diastolic blood pressure is when the left ventricle is refilling, so there’s no driving force behind the blood, even though the blood is still flowing through the arteries and veins.
Preparing a client for a blood pressure reading
Before taking someone’s blood pressure, a personal trainer should make sure the client is sitting upright with both feet flat on the floor. They should be wearing loose clothing, tight collars should be loosened and watches removed.
Readings are taken pre-exercise and the client should be relaxed. Caffeine and tobacco should be avoided as they can elevate the heart rate and alcohol can lower blood pressure.
Some people will find having their blood pressure taken a stressful experience, which can result in an elevated reading. A good personal trainer will build a rapport with their client, talk them through the process and make them feel at ease.
Taking the blood pressure reading
The fitness instructor will attach the cuff to the left arm for standardisation, two fingers’ width above the bend in the elbow and ideally in contact with the skin, with the plastic tube on the outside and in line with the brachial artery.
Once the client is relaxed, the personal trainer will start the machine and the cuff will inflate. The pressure will increase until the pulse is cut off at the systolic limit. The machine will decrease pressure, the flow of blood will continue and the diastolic reading will be taken at the point where the cuff can no longer sense the palpitation of the blood going through.
If a personal trainer is using an aneroid speedometer, they will need to listen for the blood flow to stop, loosen the cuff, then listen for the palpitations to halt.
Analysing blood pressure readings
The process of taking a client’s blood pressure should be repeated three times to get an average reading. If any of the readings vary by more than 5mg of mercury, the personal trainer should continue until they have at least two readings within 5mg. The optimal blood pressure readings are: systolic 100-120mmHg; diastolic 60-80mmHg.
Low blood pressure
If the readings are low, the client is showing signs of low blood pressure, which can make them subject to fainting, or it may be that they haven’t eaten recently. It’s a good idea for a personal trainer to address this question before the client begins any gym programme.
Any readings below systolic 100mmHg and diastolic 60mmHg, the fitness instructor should refer their client to a doctor and not exercise them that day.
High blood pressure
Readings at the higher end of normal – 120-140mmHg for systolic and 80-85mmHg for diastolic – are known as pre-hypertensive.
Readings of around 140-160mmHh systolic or 85-90mmHg diastolic represent stage 1 hypertension; readings of 160mmHg+ systolic or 90mmHg+ diastolic fall into stage 2 hypertension. Some gyms will refer a client to their GP at stage 1, some at stage 2.
Generally it’s considered worse to have a high diastolic than a high systolic rate. Equally, there’s a danger that if a client’s systolic rate is 160 while resting, it could quickly elevate to 180 or 200+ during exercise.
Blood pressure increases with age and the ASCM (American Sports College of Medicine) has provided a chart to show the mean systolic and diastolic rates for different ages and genders during a maximal treadmill exercise.
Age Men Women
SBP DBP SBP DBP
18-29 182±22 69±13 155±19 67±12
30-39 182±20 76±12 158±20 72±12
40-49 186±22 78±12 165±22 76±12
50-59 192±22 82±12 175±23 78±11
60-69 195±23 83±12 181±23 79±11
70-79 191±27 81±13 196±23 83±11
ACSM Guidelines for Exercise Testing (2000)