Fasting and Feasting for Lower Blood Pressure

How long do you usually go from your last bite of food at night to your first bite the next day? In my experience, many people tend to go between eight and 10 hours.

When you occasionally push that “no food” window closer to 16 hours, though, you enter the realm of what has come to be known as intermittent fasting. The interest surrounding intermittent fasting and human health is increasing as research into its benefits continues to accumulate.

When we engage in varying degrees of intermittent fasting, several physiological changes relevant to blood pressure take place. Scientists believe that one such change is the increased production of a protein known as BDNF, or brain-derived neurotrophic factor.

BDNF is known to stimulate brain cells to release a compound known as acetylcholine, which has two blood pressure-related effects on the body:

1. It reduces heart rate.
2. It expands the blood vessels.

In concert, these changes contribute to lowering blood pressure as part of the body’s parasympathetic or “relaxation” response in the nervous system.

For this reason, researchers are increasingly intrigued by intermittent fasting as a potential mechanism to prevent hypertension in the broader population. A recent study of 60 people living with hypertension found that intermittent fasting had the potential to contribute to lower blood pressure scores throughout the day.

While this study alone does not provide indisputable evidence that fasting should be a primary treatment option for hypertension, it contributes valuable insight into what will surely continue to be a closely followed area of study.

What is blood pressure?

Blood pressure, just like it sounds, is a measure of how forcefully the blood flowing through the body presses against the veins and arteries that carry it. When this force remains chronically high, the blood vessels are at increased risk of damage, which contributes to an increased risk of death and disease.

A healthy blood pressure reading is considered 120/80, but what do those numbers actually mean?

Systolic blood pressure

The top number, known as systolic blood pressure, is a measure of the force exerted by blood when the muscles of the heart are contracting (beating).

Diastolic blood pressure

The bottom number, known as diastolic blood pressure, is a measure of the force exerted by blood when the muscles of the heart are relaxing (between beats).

When is it hypertension?

Although it’s up to a medical professional to formally diagnose hypertension, generally a blood pressure reading creeping toward 140/90 will be enough to get you there.

Causes of high blood pressure

High blood pressure is caused by several factors, including genetics, stress, and dietary choices. Excessive sodium intake, which is a massive problem in North America, is responsible for nearly one in three cases of hypertension.

Sodium in the Canadian diet

Given these startling figures, it should come as no surprise that sodium reduction is a key step toward preventing and managing hypertension.

Check out this list of the Top 6 Sodium Culprits according to Health Canada.

Taking charge against hypertension

Dietary modification, natural supplementation, and novel approaches such as intermittent fasting all have potentially important roles to play in improving human health and in the prevention and management of conditions such as high blood pressure.

The supervision and advice of your health care professional should always be respected. High blood pressure is a serious health concern, and in some individuals, medication may be necessary for either the short or long term to reduce the risk of negative health consequences.

A version of this article was published in the February 2020 issue of alive Canada with the title “Fasting and Feasting for Lower Blood Pressure.”