Sore muscles after a workout suggest they were stressed enough to gain strength.
Greater strength is the goal, but intensive workouts can leave your muscles tender, inflamed, and tight.
And persistent post-workout soreness can hinder everyday activities and discourage future workouts.
Let's take a look at the clinical research testing omega-3s as allies against undue muscle soreness.
But first, let's review the reasons why omega-3s should and could help ease muscle soreness.
Why omega-3s may work to ease pain in muscles
The omega-3 fatty acids abundant in fatty fish — DHA and EPA – are critical players in the body's inflammation control system.
Our bodies use omega-3 DHA and EPA to create chemicals called resolvins and protectins, which the immune system uses to end or moderate inflammation.
(For more on that, see Fish Oil Linked to Lower Inflammation, Pain May be Relieved by Omega-3 Byproducts, and their links to related reports.)
Chronic inflammation is known to promote chronic conditions such as heart disease, cancer, dementia, and arthritis.
The average American's excessive intake of omega-6 fatty acids — and inadequate consumption of omega-3s — promotes chronic inflammation.
Research into the effects of supplemental omega-3s on post-exercise inflammation and related muscle soreness has been limited, but preliminary indications have been positive.
For example, see Omega-3s for Exercise: Trials Find Muscle and Breathing Benefits.
Texas trial in women finds fish oil reduced muscle soreness
Earlier this year, researchers from Baylor University in Texas published encouraging findings.
They conducted a clinical trial designed to examine the effects of supplemental fish oil on muscular soreness in women following strength training (Tinsley GM et al. 2016).
In this placebo-controlled, double-blind trial, “regular”, non-athletic women were assigned to one of two groups:
• Fish Oil — 6 grams of omega-3 fish oil per day
• Placebo — 6 grams of corn oil or soy oil per day
We should note that the fish oil contained an unusually high 5:1 ratio of EPA to DHA, while most fish oils provide only about twice as much EPA as DHA.
The researchers may have thought that a higher EPA to DHA ratio would have a more powerful anti-inflammatory effect.
After taking the supplement or placebo for a week, the women in the study participated in a single round of strength training, doing elbow flexion and leg extension exercises to the point of fatigue.
The women then reported their perception of muscular soreness every day over the following week, while continuing to take either fish oil or a placebo.
In addition, the research team also recorded the women's reports of soreness while they did functional movements, 48 hours after the single workout, and again one week later.
The women in the fish oil group reported 33% to 42% less muscle soreness when sitting still and moving than the control group.
The researchers believe that omega-3 supplementation holds significant promise for reducing post-workout muscular soreness.
Of course, 6 grams of omega-3s a day is an unusually high dose.
Most health authorities recommend that adults get a minimum of 250 mg to 500 mg of omega-3 DHA plus EPA per day
But clinical trials of limited duration — such as this one — often employ high doses of a substance undergoing tests, in order to gain a clear effect in a short period of time.
It seems likely that a lower dose — such as 2 to 3 grams of DHA plus EPA per day — would be likely to exert beneficial, though perhaps not as dramatic, effects.
Japanese clinical trial echoes the Texas results
Last June, researchers from several Tokyo universities published the results of a clinical trial in 24 healthy men (Tsuchiya Y et al. 2016).
The participants were randomly assigned to take fish oil or placebo capsules for eight weeks prior to prescribed daily weightlifting (bicep curls), and to continue taking them for five days.
The fish oil group took capsules containing 600 mg of EPA and 260 mg of DHA per day, and performed five sets of six bicep curls every day.
At the end of the study period, the fish oil group had gained extra range of motion and bicep contracting power, while enjoying reduced muscle soreness.
Omega-3s cut post-exercise inflammation in non-athletes
An earlier study by Saint Louis University researchers tested the effects of omega-3s on exercise-induced inflammation (Jouris KB et al. 2011).
The male participants performed bicep curls on two separate occasions – once after 14 days of no omega-3 supplements, and again after seven days of daily supplementation with 3,000 mg of omega-3s.
Before and 48 hours after bicep exercises, signs of inflammation were measured – participants reported their perception of muscle soreness, swelling in the muscles was measured, and the temperature of the skin was recorded.
The results showed that 3,000 mg of supplemental omega-3s minimized the severe, delayed-onset muscle soreness that results from strenuous strength exercises.
As the Saint Louis scientists said, these results suggest that fish oil could alleviate muscle pain among novices and serious athletes alike:
“Based on these findings, omega-3 supplementation could provide benefits by minimizing post-exercise soreness and thereby facilitating exercise training in individuals ranging from athletes undergoing heavy conditioning to sedentary subjects or patients who are starting exercise programs or medical treatments such as physical therapy or cardiac rehabilitation.”
Three weeks of omega-3s improved performance
The athletic benefits of omega-3 fish oil may extend beyond pain relief to enhanced performance.
In a study involving 30 male athletes, serious cyclists were given either a seal oil supplement rich EPA and DHA or a placebo (olive oil) for 21 days.
The athletes' muscular performance was measured, and they reported their perception of post-exercise fatigue (Lewis EJ et al. 2015).
After three weeks, the fish oil group experienced a 20% increase in muscle function.
According to the researchers, this was a result of fish oil boosting the body's “neuromuscular performance”.
In addition, the athletes in the fish oil group experienced less muscular fatigue from intensive training (17 hours a week) compared to the control group.
Scottish study is an outlier
One study found reduced inflammation after exercise, but nothing else.
That Scottish study, conducted in 20 men, found that supplemental fish oil reduced markers of inflammation and DNA damage following six weeks of prescribed exercise (Gray P et al. 2014).
However, the men in the fish oil group did not report reduced muscle soreness.
We couldn't discover the dose of omega-3s used, so it's possible that they weren't getting enough to produce results within six weeks.
Still, most of the published clinical evidence suggests that omega-3 fish oil does reduce exercise-related muscle soreness.
It can't hurt to try omega-3s
Most of the relevant research on omega-3s is encouraging.
This may not matter a great deal to those of us whose resistance exercise consists of some push-ups or light weight lifting.
But it certainly can matter when it comes to serious strength training with weights or machines, and to intensive interval training, such as sprinting.
As we described, there are sound biological reasons why omega-3 fish oil might reduce muscle soreness.
And, it seems plausible that regular consumption of omega-3s from seafood or supplements may reduce muscle soreness and increase muscle performance.
The doses used with success were several times higher than the doses recommended for general health.
But the positive outcomes of most studies suggest that lower, but substantial doses may, over a long period serve to ease soreness.
And since omega-3s offer so many other benefits, it can't hurt to try higher doses if muscle soreness has been a barrier to reaching your exercise goals.