Medically reviewed by Lindsay Cook, PharmD
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- Omega-3s may slightly lower resting heart rate, but the effect is small.
- High-dose omega-3 supplements may increase the risk of atrial fibrillation in some people.
- Omega-3s from food sources like fish are generally safer and may offer added heart benefits.
Omega-3s are among the most popular supplements for heart health. They are frequently taken to help reduce risk factors, such as high triglycerides, in people with heart conditions. But can omega-3s influence heart rate, and should people with heart rhythm conditions like atrial fibrillation be cautious? We spoke with a pharmacist about how omega-3s affect heart rate, heart rhythm, and overall cardiovascular function.
Do Omega-3s Lower Resting Heart Rate?
People with elevated heart rates sometimes turn to omega-3 supplements, hoping to lower their resting heart rate and support overall heart health.
"Some studies have shown decreased heart rate with omega-3s," Christine Cadiz, PharmD, a clinical pharmacist in cardiology at UC Irvine, told Health.
A 2023 study in people with atrial fibrillation, also known as A-fib, showed that the participants with higher total omega-3 fatty acid blood levels and higher docosahexaenoic acid (DHA) levels had lower heart rates. This suggests that higher omega-3 levels may be associated with lower heart rates.
However, studies have found omega-3s typically lower heart rate by only about 2 to 3 beats per minute, which is a small change, according to Cadiz. However, if that reduction is maintained over time, it could have meaningful benefits for heart health.
Omega-3s may help lower heart rate through their anti-inflammatory effects and by influencing the electrical signals in heart cells. However, the mechanisms aren’t fully understood.
Can Omega-3s Raise Heart Rate or Trigger Arrhythmias?
Heart rate refers to the speed of your heartbeats, measured as beats per minute, while your heart rhythm is the pattern of your heartbeats and how regular they are.
A-fib, a heart rhythm disorder, can cause the heart to beat irregularly and often much faster than normal, sometimes causing sensations of fluttering or a pounding heartbeat.
While omega‑3s may offer benefits for some cardiovascular outcomes, they may modestly increase the risk of A-fib in certain people, particularly older adults or those with preexisting heart disease.
For example, a 2024 review found that high-dose omega-3 supplements of 1–4 grams per day were associated with a dose-dependent increase in A-fib risk. Doses around 1 gram per day raised A-fib risk by about 12%, while doses of 1.8–4 grams per day increased risk by roughly 50%.
"This increased risk of A-fib was seen in patients both with and without underlying cardiovascular disease, with a higher risk in those with a history of myocardial infarction (heart attack)," said Cadiz.
Does Food vs. Supplements Make a Difference?
When it comes to A-fib, how you consume omega-3s matters. Higher dietary intake of omega-3s from foods like fatty fish was generally associated with a lower risk of A-fib, meaning that food-based sources of omega-3s don’t pose the same risk.
This may be because food sources do not contain as high a concentration of omega-3s as supplements, though more research is needed.
“Compared to fish oil, eating fatty fish provides additional benefits, such as vitamins and protein,” said Cadiz. Cadiz noted that for those who aren’t able to meet the American Heart Association’s recommendation of at least two 3.5-ounce servings of fish per week, especially fatty fish, omega-3 supplements may be helpful.
However, it's important to speak with a healthcare provider before starting a supplement, particularly if you have a heart condition or take medications.
Who Should (and Shouldn’t) Take Omega-3s for Heart Health?
Omega-3 supplementation can be especially beneficial for certain populations, such as those with high triglycerides. "Those that have high blood lipids, particularly elevated triglycerides, may benefit most from prescription omega-3 fatty acids," noted Cadiz.
Research shows that higher doses of omega-3s can be effective for lowering triglyceride levels.
They may also be a good option for people who don’t eat fish, as they can help maintain healthy omega-3 levels, which are important for overall heart health.
However, people with a history of A-fib or other arrhythmias should discuss omega-3 supplement use with their healthcare provider to make sure it’s safe.
