You probably take probiotics for your gut. New research suggests they might also be helping your lungs and heart work more efficiently during exercise.
The Study
Probiotics are a $10.5 billion industry, and that number keeps climbing—most of the sales pitch centers on digestion and immune health. A new meta-analysis sought to determine whether there’s more to the story.
Researchers combined data from 21 studies covering 685 people to see if taking probiotics actually changes physical performance, not just gut symptoms.
The Big Winner: VO2 Max
The results zeroed in on one metric: VO2 max, the measurement of how well your body uses oxygen during exercise, widely considered the gold standard for cardio fitness. Cycling-based VO2 max testing showed the biggest jump in the entire analysis. Overall aerobic endurance improved too.
Here’s what didn’t budge: muscle strength, agility, sprint speed, and change-of-direction tests. Based on this data, probiotics aren’t a strength supplement. They’re an endurance supplement.
The Dose and Strain That Worked
Because the analysis pulled from 21 different studies, dosages varied. Only doses between roughly 1 billion and 100 billion CFU (colony-forming units) per day showed a benefit — good news, since that’s the range most probiotic products on store shelves already fall into.
Strain type mattered more than expected. Multi-strain and single-strain products both worked, with multi-strain edging out slightly ahead. But only one specific strain, Lactobacillus plantarum, showed a clear, statistically significant benefit on its own. If performance is the goal, check the label for that name specifically.
How Long Until You’d Feel It
Don’t expect overnight results. Benefits started showing up around 30 days in, and the biggest gains were predicted between 90 and 110 days of consistent use. That timeline tracks with how probiotics typically work: they need time to settle into your gut microbiome before any downstream effects kick in.
Worth Adding to Your Routine?
This research suggests probiotics’ reputation may be underselling what they actually do. If you’re chasing better endurance or conditioning, a probiotic supplement with Lactobacillus plantarum on the label, taken daily for at least a few months, could be a simple, low-risk addition to your training.
The information in this article is for educational purposes only and is not a substitute for personalized medical or nutritional advice. Talk with a physician or registered dietitian before adding a new supplement to your routine, especially if you have an existing health condition.
