IMPACTS OF EXERCISE ON BLOOD PRESSURE: ACUTE & CHRONIC
You’re at your doctor’s office for a routine check up, a possible sinus infection, or some other sickness, and you enter the waiting room with a nurse. Typically, one of the first things they'll assess is your blood pressure. You’re already nervous and now your blood pressure is higher than it should be.
What does high blood pressure actually indicate, though?
And how do you address it?
Today, I’m going to help you understand this metric, why it’s important for overall health and how exercise can greatly impact blood pressure both acutely and for the long haul.
LET'S GO OVER THE BASICS
High blood pressure, also known as hypertension, is when your blood pressure, the force of blood flowing through your blood vessels, is consistently too high.
This is an incredibly common occurrence among adults in the United States and can easily go undetected for years, causing increased stress on the body and poorer health outcomes.
Blood pressure is categorized by two numbers, a systolic mmHg (which is the upper number) and a diastolic mmHg (which is the lower number). (mmHG stands for millimeters of mercury, which is how blood pressure is measured).
Systolic blood pressure: the pressure exerted against artery walls when the heart is actively beating
Diastolic blood pressure: the pressure exerted against artery walls when the heart is resting
A typical, normal blood pressure, as defined by the American Heart Association is anything less than 120/80 mmHg.Anything above this is categorized as elevated or high, and is then broken into stages depending on how much higher it is.
So why is knowing all of this important? High blood pressure affects your cardiovascular system, and is a risk factor for things such as heart attacks and strokes. Having a normal blood pressure reduces your risk for both these and other health issues.
WHERE DOES EXERCISE COME INTO PLAY?
Although medications are known to be effective for lowering hypertension and, in many cases, shown to be more effective than exercise protocols, some studies show that exercise can be just as effective as medications in lowering systolic blood pressure.
Exercise is the first line of defense when diagnosed with elevated or high blood pressure, so when done consistently, can be used as a preventative measure to avoid daily medications and the eventual development of further cardiovascular risk (Naci et. al 2018).
A meta-analysis on the effects of regular aquatic exercise showed a net decrease in -8.4mmHG SBP and -3.3mmHg DBP in patients with hypertension (Igarashi, Nogami 2020).
With results like these, I want to emphasize how important exercise is for long term health–and that means exercise in any form. We know exercise can help us lose body fat and gain muscle, but to extend our lives and improve the quality of our lives in later years is a completely different ball game, and one you should consider just as important as losing that extra 5lbs.
HOW DOES EXERCISE AFFECT BLOOD PRESSURE ACUTELY AND CHRONICALLY?
Research tells us that active individuals have a lower risk for becoming hypertensive versus sedentary individuals. Acutely (short-term), evidence shows that in the post-exercise or recovery window, up to 22 hours post exercise. This impacts both healthy individuals who do not have hypertension, as well as those with hypertension. The higher your blood pressure, the greater reduction in blood pressure typically seen.
In theory, the idea of exercising every other day should inherently help reduce the likelihood of higher blood pressure numbers with this concept. Long term, a loss of body fat, an increase in musculature, and consistent exercise shows these same effects, of a decrease in both systolic and diastolic blood pressure numbers. Endurance exercise has shown to be used primarily in studies (walking, running, swimming, etc), but we know that strength training is still an important part of the equation.
The exact methods of how exercise impacts blood pressure is not entirely known, but is believed to impact the following:
Impact insulin sensitivity in a positive way (also great for pre-diabetics and diabetics); You want your body to be sensitive to insulin, as it is the hormone that controls blood glucose levels. Being less sensitive means your body cannot regulate blood glucose, leading to insulin resistance and diabetes.
Alter vasoconstrictors and vasodilators: Your blood vessels will open wider and constrict more, increasing or decreasing blood flow based on signals sent from the brain. When you take aspirin for a headache, this works as a vasodilator, opening up your blood vessels for increased blood flow. Exercise typically leads to vasodilation to allow more nutrients and oxygen to get to the muscles working.
Decrease catecholamines: The most common catecholamines are epinephrine, norepinephrine, and dopamine, so think fight or flight responses. This is your body’s way of dealing with stress. We know that exercise leads to an increase in concentrations of these in your body, which leads to an increase in blood pressure during exercise. However, the impacts of this lead to a lowered response at rest.
Decrease total peripheral resistance: TPR is the amount of force on blood flowing through all the blood vessels in your body). If we are thinking of what blood pressure is, TPR is the overarching umbrella for this. Lowered TPR is due to a lower cardiac output and stroke volume (how blood is moving through your body). A lower TPR means there is less total pressure throughout the body’s vascular system. (from the ACSM position stand on Exercise and Hypertension).
HOW TO APPLY THIS KNOWLEDGE
That may have been a lot to understand, so let’s think simply on how to apply this knowledge. The FITT principle (frequency, itensity, time, type) applied to this population (those with hypertension and those wishing to prevent it) should be exercising:
Frequency: On most days of the week
Intensity: 40-60% VO2 Reserve, or think at a moderate intensity
Time: Greater than or equal to 30 minutes continuous or accumulated effort (10 minute bouts of walking have been shown to help reduce risk of CVD)
Type: primarily endurance physical activity (cardio) with supplemental resistance training (at least 2x/week hitting all major muscle groups).
*This principle is an ACSM guideline for those with hypertension or elevated blood pressure. Please consult with your doctors and health professional team before starting a new exercise regimen if you currently have high blood pressure, or are on medications that impact blood pressure).*
UNTIL NEXT TIME - COACH SHELBY