News

The discovery

A supplement widely promoted for athletic performance may interfere with some of the heart’s beneficial adaptations to exercise, according to new Dalhousie University research published in Scientific Reports.

Key findings
 

• While these supplements are often promoted to support exercise performance and cardiovascular function, researchers found the combination of sodium nitrate and running prevented several beneficial cardiac improvements normally associated with exercise in females.
  
  
• Those benefits included changes linked to heart structure, ventricular function and calcium handling in heart cells, which helps regulate contraction and relaxation. The effects were much less pronounced in males, pointing to important sex differences that researchers say are too often overlooked in supplement research.

Why it matters

The findings challenge the assumption that supplements commonly associated with athletic performance are automatically beneficial, particularly when combined with exercise. They also underscore the need to study females directly, rather than assuming results observed in males apply equally across sexes.

We expected nitrates and exercise to work together to improve heart health. Instead, in females, the supplement prevented many of the positive cardiac adaptations normally produced by exercise.

— Dr. Susan Howlett, the study's corresponding author and a professor in Dalhousie’s Department of Pharmacology, who led the study with PhD student Elise Bisset, who is now a postdoctoral fellow at the Université de Montréal.

How the research was done

The study examined sodium nitrate, a compound commonly found in beetroot-based endurance products marketed to runners, cyclists and fitness enthusiasts. Before people change their workout routines, researchers caution that the study was conducted in mice and more work is needed to determine whether the same effects occur in humans. But they say the results raise important questions about the cardiovascular effects of long-term nitrate supplementation, especially among people using these products alongside regular aerobic exercise.

Learn more 

Paper: "Sodium nitrate supplementation prevents beneficial cardiac adaptations to running in female mice with few effects on male hearts"

Researchers: Dr. Susan Howlett l Elise Bisset