New Study Finds Strong Legs Could Be Key to Strong Heart

PRAGUE, Czechia — Patients with especially strong legs are less likely to develop heart failure following a heart attack, according to a new report from the European Society of Cardiology.

Myocardial infarction (a heart attack) is the most common cause of heart failure, with roughly 6%-9% of heart attack patients going on to develop a form of heart failure.

Prior studies had revealed having strong quadriceps — the large muscle at the front of the thigh — has an association with a lower risk of death among patients with coronary artery disease.

For this latest project, the study authors tested their hypothesis that leg strength does indeed have a link to a lower risk of heart failure following acute myocardial infarction. 

This study encompassed 932 patients hospitalized between 2007 and 2020 who had experienced an acute myocardial infarction. 

All of the patients exhibited no sign of heart failure before entering the hospital, and did not develop heart failure complications during their hospital stay. The average age of these patients was 66 and 81% of the participants were men.

“Our study indicates that quadriceps strength could help to identify patients at a higher risk of developing heart failure after myocardial infarction who could then receive more intense surveillance,” said study author Kensuke Ueno, a physical therapist at the Kitasato University Graduate School of Medical Sciences in Sagamihara, Japan. 

“The findings need to be replicated in other studies, but they do suggest that strength training involving the quadriceps muscles should be recommended for patients who have experienced a heart attack to prevent heart failure,” Ueno added.

In order to determine leg strength, the researchers measured maximal quadriceps strength. 

They did this by having patients sit on a chair and contract their quadriceps muscles as hard as possible for five seconds. A handheld dynamometer attached to the patient’s ankle recorded the maximum value in kilograms. 

The measurement was performed on each leg and the researchers used the average of both values. 

The strength of the patient’s legs was then expressed relative to body weight, meaning that quadriceps strength in kilograms was divided by body weight in kilograms and multiplied by 100 for a % body weight value. 

Patients were classified as “high” or “low” strength according to whether their value was above or below the median for their gender.

The median value for women was 33% body weight and the median value for men was 52% body weight. 

Through this process, the researchers determined a total of 451 patients had low quadriceps strength and 481 had high strength. 

During an average follow-up of 4 1/2 years, 67 patients (7.2%) developed heart failure. The incidence of heart failure was 10.2 per 1,000 person-years in patients with high quadriceps strength and 22.9 per 1,000 person-years in those with low strength.

The researchers analyzed the association between quadriceps strength (low vs. high) and the risk of developing heart failure, adjusting for factors such as age, sex, body mass index, prior myocardial infarction or angina pectoris, diabetes, atrial fibrillation, chronic obstructive pulmonary disease, peripheral arterial disease and kidney function. 

Compared with low quadriceps strength, a high strength level was associated with a 41% lower risk of developing heart failure.

The investigators also analyzed the association between quadriceps strength as a continuous variable and the risk of developing heart failure. They found that each 5% body weight increment in quadriceps strength was associated with an 11% lower likelihood of heart failure.

Dan can be reached at [email protected] and @DanMcCue