What is it?
Blood pressure is the measurement of the pressure inside arteries. Arteries are the blood vessels that take blood away from the heart for delivery to the body.
When assessing blood pressure two measures are taken, the systolic blood pressure and the diastolic blood pressure.
Systolic blood pressure
Systolic blood pressure is the higher reading on a blood pressure measurement. The systolic pressure coincides with the heart squeezing and pumping blood out of the heart. This squeezing of the heart sends a pressure wave through the arteries.
Diastolic blood pressure
Diastolic blood pressure is the lower reading on a blood pressure measurement. The diastolic pressure coincides with the heart relaxing between beats.
Reporting blood pressure
Blood pressure is usually reported as the systolic reading over the diastolic reading. For example, a systolic blood pressure of 124mmHg and a diastolic blood pressure of 76mmHg would be described as “a blood pressure of 124 over 76” and written as 124/76.
Other factors can affect blood pressure
There are many other factors that can affect blood pressure other than insulin resistance. Blood pressure can suddenly increase with factors such as mental stress or physical exertion. Therefore it is important to measure blood pressure after a period (at least a few minutes) of calm. It may be necessary to recheck blood pressure a few times to achieve a more accurate reading. Blood pressure can also be affected by other health conditions and therefore a high blood pressure does not always mean insulin resistance. However, insulin resistance is probably the most common cause for high blood pressure.
What is the healthy range?
A lower blood pressure indicates better health. In healthcare, blood pressure is graded depending on how high it is.
- A blood pressure of less than 130/85 is considered normal.
- A blood pressure of less than 120/80 is considered ideal.
How is blood pressure categorised in healthcare?
- Ideal is a systolic of less than 120 and diastolic of less than 80
- Normal is a systolic of less than 130 and diastolic of less than 85
- High-normal is a systolic of 130-139 or a diastolic of 85-89
- Grade 1 hypertension is a systolic of 140-159 or a diastolic of 90-99
- Grade 2 hypertension is a systolic of 160-179 or a diastolic of 100-109
- Grade 3 hypertension is a systolic of above 179 or above 109
Why does it increase with insulin resistance?
Blood pressure increases with insulin resistance due to at least two mechanisms:
- Insulin resistance of the small muscles that surround blood vessels prevents the muscles from relaxing. This causes the blood vessels to squeeze harder, increasing blood pressure.
- The kidneys play a central role in controlling blood pressure. A high insulin level, that happens with insulin resistance, alters how the kidneys function and raises blood pressure.
A high blood pressure may need medical attention.
- For people not known to have high blood pressure already a systolic blood pressure above 140 or a diastolic blood pressure above 90 should be routinely reviewed by an appropriate healthcare professional.
- Everyone with a systolic blood pressure of 180 (or more), or a diastolic blood pressure of 120 (or more) should be urgently reviewed by an appropriate healthcare professional. Urgent means the same day.