Heart Disease Prevention and Lifestyle Factors: How Much Do They Matter?
By Morris Hasson, MD
The numbers illustrate just how prevalent heart disease still is among Americans: at age 40, approximately 1 in 2 men and 1 in 3 women will develop heart disease in their lifetime; at age 70, the risk for men is 1 in 3 and 1 in 4 for women. But these statistics only tell half the story. The role of lifestyle factors in preventing heart disease is the other, and more important part, given their power to dramatically change these numbers.
Consider how much progress has already been seen: from 1980 to 2000 the death rate from heart disease for men and women in the US fell by approximately 50%, and in the following decade, plunged another 31%. About half of this is attributed to improvements in how we are able to treat heart attacks with advances in stents, bypasses and the medical management of patients in the hospital. The other half is due to an increased focus on preventive measures, specifically:
Cholesterol control, accounting for approximately 50% of the improvement seen as a result of prevention
- Smoking cessation, 25%
- Blood pressure control, 25%
I can’t emphasize enough the importance of knowing that preventive measures, which include modifying lifestyle factors, is responsible for fully half of the significant decline in heart disease in the US. That finding is pivotal in guiding our approach to heart health with each individual patient.
Know your heart disease risk factors…and take control of them
The vast majority of people who develop heart disease do so for reasons known as risk factors. These include smoking, high blood pressure, high cholesterol, diabetes, and a family history of premature heart disease, defined as a heart attack or stent prior to age 55 for men and age 65 for women. Most of these can be controlled through a combination of appropriate medications and modification of lifestyle factors, as explored below.
For those at risk, maintaining healthy levels of cholesterol in the blood with statin medications is one of the most important strategies we have for preventing heart disease. These not only block the liver from manufacturing cholesterol but also reduce plaque rupture in the arteries.
Why is preventing plaque rupture so important? Sadly, for up to 30% of people, heart disease is only discovered when they have a fatal heart attack, and we have only recently begun to understand why. People have symptoms of heart disease when the demand for oxygen in the heart muscle is greater than the amount of oxygen delivered through a narrowed artery. For decades it was thought that an artery in the heart became narrowed at a very slow rate until it could no longer supply enough oxygen to the heart muscle. Further, it was thought that problems wouldn’t occur until the artery was more than 70% blocked. However, this idea of a slow, gradual narrowing of the arteries occurs only in about 10-15% of people.
In the mid-1990s it was discovered that the majority of heart attacks were not from a slow, gradual narrowing of the artery but occurred from a sudden avalanche of cholesterol. Cholesterol stored in artery walls suddenly fell into the bloodstream in a process called “plaque rupture.” In most people, cholesterol is not deposited in an inward direction, narrowing the artery, but is deposited outward into the artery wall. Imagine a cholesterol-filled blister in the artery wall that over time “ruptures” its contents which fall into the bloodstream suddenly, like a lava flow or an avalanche. Prior to the plaque rupture, these arteries were only about 40% to 50% blocked, which would provide plenty of oxygen during strenuous exercise, and little to no warning that a heart attack was likely to occur.
Another controllable and significant factor in preventing heart disease, the benefits from quitting smoking happen rather quickly. It is estimated that the risk of heart disease is about 40% lower within just two to five years of quitting smoking, making a convincing case for never being too old to receive the health benefits of eliminating tobacco.
Blood pressure control
Another key piece of the heart disease prevention puzzle is controlling blood pressure by promptly identifying and treating higher-than-normal blood pressure with lifestyle changes and medication when appropriate.
Blood sugar control
Type 1 and type 2 diabetes have also been identified as important risk factors for cardiovascular disease if poorly controlled, harming blood vessels and leading to hardening of the arteries. The first line of defense in achieving optimal blood glucose levels is by making dietary modifications to limit carbohydrate and sugar intake and manage weight, and adhering to a regular schedule of aerobic exercise.
Obesity is considered a major modifiable risk factor for heart disease by the American Heart Association. Weight gain negatively affects many other risk factors for heart disease, namely cholesterol, blood sugar and blood pressure. It is unclear if the higher risk associated with obesity is related to the increased levels of cholesterol, blood sugar and blood pressure or if there is something else at work here.
There is a somewhat surprising and very large amount of evidence showing that lack of physical activity is a major risk factor for heart attacks and strokes, similar to smoking, high cholesterol and high blood pressure. Regular physical activity is defined as 30 minutes of moderate exercise (such as walking at a speed of three to four miles per hour, gardening or leisurely riding a bike) five days a week; or more vigorous exercise, such as running, for 20 minutes, three times a week.
Make a plan…consult with a primary care physician
Begin with a visit to a primary care physician to understand individual risk factors and create a plan for lifestyle modifications and any appropriate medications. Take the time to consider:
“Borderline” blood pressure or cholesterol
As an internal medicine specialist for more than 30 years, I am saddened to see the number of patients who may have struggled with “borderline” blood pressure or cholesterol for decades. It is not hard to imagine the damage done to our hearts from simply watching “borderline” blood pressure and/or cholesterol for decades. The first recommended approach would be modifying lifestyle factors such as weight loss, diet and exercise to improve blood pressure and cholesterol levels. If these efforts prove unsuccessful within six to 12 months, it is essential to consider stepping in to treat with medicines. This can be a temporary or longer-term solution, as we realize for some people, it may require years before they successfully make lifestyle changes that can meaningfully lower their risk of heart disease.
Treating to the goal
I also find missed opportunities when people with cholesterol or blood pressure risk factors are treated and see improvements, but not enough to meet overall goals for ongoing prevention of heart disease. For example, a person may successfully use a combination of lifestyle changes and medications to lower their blood pressure from 170/100 to 145/92. While this is significant and represents an improved reduction in the risk for heart disease, it should be tailored to the individual by balancing their other risk factors as well as side effects if medicines are taken.
Early warning signs
Many people don’t attribute mild or unusual symptoms as an early warning of heart disease, but only expect the classic symptoms seen in movies, such as chest pressure severe enough to make them stop what they are doing, shortness of breath and left arm or neck pain. This actually occurs in only 10 to 15% of people experiencing heart attacks, while milder symptoms that are harbingers of heart disease are often overlooked until they suddenly become severe. I encourage patients to call immediately if they experience any unusual symptoms, especially if related to exertion – shortness of breath earlier than usual or experiencing heartburn during or after exercise.
To answer the question posed at the beginning of this blog, decades of research continue to prove that lifestyle factors – modifiable and controllable – matter greatly in maintaining a heart-healthy profile. Ceasing to smoke and controlling cholesterol, blood pressure, blood sugar, obesity and pursuing regular, moderate activity hold the key to preventing and lowering the risk of dying from a cardiac event.