The Cooper Institute

Founded in 1970 by the "Father of Aerobics"
Kenneth H. Cooper MD, MPH


Can a Stroke Be Prevented?

Posted in

Friday, May 07, 2021

Stroke, which is also known as a cerebrovascular accident, is a form of cardiovascular disease that affects the arteries of the brain. A stroke occurs when an artery bringing oxygen and nutrients to the brain is blocked by plaque and blood clots (ischemic stroke), or when an artery in the brain bursts (hemorrhagic stroke).

According to the 2021 statistical update from the American Heart Association, approximately 795,000 strokes occur annually in the United States. Ischemic strokes account for about 87% of all strokes, while hemorrhagic strokes account for about 13%. In addition to being the leading cause of long-term disability, stroke also causes about 148,000 deaths each year in the U.S. Annual health care costs related to stroke are estimated at $50 billion.

Oftentimes, the person having the stroke is unaware of what is occurring. To compound this situation, many people are unaware of the warning signs of a stroke, which is the major reason why only about 10% of all stroke victims obtain the best treatment available. It is not uncommon for several hours to elapse from the time the stroke occurs until the victim arrives in the emergency room. Half of all the damage caused by stroke occurs within the first 90 minutes, while 90% of the damage occurs during the first three hours.

The warning signs of stroke include the following:

  • Sudden weakness or numbness of the face, arm, or leg on one side of the body 
  • Sudden dimness or loss of vision, particularly in one eye 
  • Loss of speech, trouble talking or understanding speech
  • Mental confusion; sudden loss of consciousness 
  • Sudden severe headache with no known cause  
  • Unexplained dizziness or sudden falls

Only ~70% of the U.S. population is able to identify just one of these warning signs of stroke. So, it should be obvious at this point that the degree of disability and the number of deaths from stroke could be markedly reduced if the public was better able to recognize the warning signs and acted accordingly (i.e. call 911) more quickly.

Risk Factors and Stroke Prevention

Risk factors are behaviors or characteristics that increase the likelihood of disease.  Some risk factors cannot be changed, while others can be changed by lifestyle modification or medication. Among the risk factors for stroke that cannot be changed are age, sex, family history of stroke, ethnicity, previous stroke, previous heart attack, and low birth weight. However, there are many other risk factors for stroke that can be significantly improved by lifestyle modification and/or medication. These include:

What about Exercise and Diet for Preventing Stroke?

An important study utilizing Cooper Clinic patients was published in Stroke. After completing a medical exam, including a maximal treadmill exercise test, a total of 46,405 apparently healthy men and 15,282 apparently healthy women were followed for an average of 17.5 and 16.3 years, respectively. A total of 692 strokes occurred among the men, and 171 strokes occurred among the women. Men and women were placed into four groups (quartiles) of cardiorespiratory fitness based on their treadmill test performance and age. For both genders, the risk of stroke was lower in quartiles 2-4 when compared to the reference group (quartile 1). For example, men who scored in the highest quartile of CRF were 40% less likely to experience a stroke during the follow-up when compared to men in the lowest quartile. A similar trend was seen in women. In both men and women, the overall trend for decreased stroke risk across cardiorespiratory fitness groups was significant. These results are shown in the Figures below.

From a dietary perspective, adherence to a Mediterranean-style diet high in olive oil, nuts, and other plant-based foods have been associated with a nearly 50% reduction in stroke risk when compared to a typical diet.

Regular consumption of fatty fish is also associated with a significantly decreased risk of stroke; scientists speculate that omega-3 polyunsaturated fats that are found in fatty fish may be responsible for this. Conversely, the Nurses’ Health Study showed that each 1 daily serving increase in sugar-sweetened soda was associated with a 13% increased risk of stroke.

So there you have it. Many strokes occur as a result of poor lifestyle, and are therefore, preventable. Furthermore, the number of stroke deaths and the degree of disability from non-fatal strokes could be greatly reduced if the public was more aware of the risk factors and warning signs of stroke, and if emergency help was summoned much more quickly.    


American Heart Association. Heart disease and stroke statistics-2021 update. Circulation. 143(8):e254-e743

Hooker, S.P., et al. (2008). Cardiorespiratory fitness as a predictor of fatal and nonfatal stroke in asymptomatic women and men. Stroke. 39:2950-2957.