Strength Beyond the Barbell
When we talk about resistance training, we usually focus on the obvious benefits such as building strength, gaining lean muscle, and improving bone density. And rightly so. These outcomes are valuable, measurable and easy to communicate to clients. But for those of us in the fitness profession, it’s worth exploring what else strength training can do, in particular, the benefits that aren’t immediately visible in the mirror or on the scale.
What if we told you that resistance training might also support emotional wellbeing and gut health? That it could play a role in helping your clients feel better mentally, not just physically? That’s not a marketing hook. It’s something science is starting to support. And as fitness professionals, we’re in a prime position to bring this knowledge into our sessions and conversations.
Let’s take a closer look at how lifting weights could also lift mood and take a look at what’s going on in the gut, which might explain it.
The Gut-Brain Axis and Why It Matters for Mental Health
If you’ve been keeping an eye on the research over the past few years, you’ll have seen a growing interest in something called the gut-brain axis. It’s the idea that the gut and the brain are in constant communication. The gut sends signals to the brain through neural, hormonal and immune pathways. This cross-talk can influence mood, cognition and even behaviours like anxiety or motivation.
A key player in this relationship is the intestinal barrier, that is the selectively permeable lining that separates our bloodstream from the contents of the gut. When this barrier is compromised, substances like lipopolysaccharide (LPS), a toxin found in the cell walls of certain bacteria, can leak into circulation. The body sees LPS as a threat, sparking inflammation that can affect the brain as well as the rest of the body.
LPS itself is hard to measure in humans, so researchers often track something called lipopolysaccharide binding protein (LBP) in the blood. Higher levels of LBP are associated with greater intestinal permeability, commonly referred to as “leaky gut”, has been linked to mood disorders like depression.
It’s a fascinating, emerging area which begs the question, “Can we use exercise, such as resistance training, to help maintain or even improve the integrity of the gut barrier and support better mental health?”
Resistance Training Improves Mood & Gut Health
A 2025 randomised controlled trial by Dow and colleagues set out to explore this very question. The researchers recruited 20 sedentary but otherwise healthy adults, all in their late 30s to early 40s. One group followed an 8-week resistance training programme 3 days a week, progressing from 45% to 80% of estimated 1RM. The other group acted as a waitlisted control.
They measured strength (via bench press and split squat), mood (using validated surveys like POMS and CES-D), and markers of gut permeability (specifically, serum LBP).
After 8 weeks, the results were quite something:
- The resistance training group saw a 74% increase in total strength. That’s impressive in its own right, but not unexpected for previously untrained individuals.
- More interestingly, their serum LBP levels dropped by 16%, while the control group’s LBP levels actually increased by 9%. This suggests an improvement in gut barrier function for those who were training.
- Mood also improved in the training group. Their POMS scores, which assess mood states like tension, fatigue, and confusion, showed a significant improvement compared to the control group.
Importantly, the improvements in strength, gut health and mood were not directly correlated. This shows the mood boost wasn’t just down to getting physically stronger and the better gut health wasn’t simply a by-product of improved fitness. Resistance training seems to be doing something more holistic here.
What Else Does the Evidence Say?
The Dow study isn’t the only one pointing to this broader benefit of lifting weights. A meta-analysis by Gordon et al. (2018) pulled data from over 30 trials and found that resistance training significantly reduced depressive symptoms, even in people with clinical depression. This wasn’t about getting shredded or benching twice your bodyweight, just the act of engaging in structured resistance training seemed to help improve mood.
Another study by Moore et al. (2022) explored gene activity in the gut following a 6-week resistance training programme in older men. Although it didn’t measure mood, the researchers found changes in genes linked to mucin biosynthesis, which supports the gut lining and reductions in genes associated with LPS production. That points to a gut that’s better protected and less inflamed.
Then there’s work by Broadhouse et al. (2020), which looked at older adults with mild cognitive impairment. After completing a resistance training programme, participants showed changes in hippocampal plasticity. This is a fancy way of saying the brain was adapting and potentially improving memory and cognition.
How Does It Work?
So we know resistance training can improve mood and gut health, but how exactly does it work? What’s going on inside the body that helps explain these changes?
Researchers are still piecing the puzzle together, but a few standout mechanisms are beginning to emerge. These aren’t just theoretical. They’re grounded in biology and supported by growing evidence.
One key player is brain-derived neurotrophic factor, or BDNF. Often described as “fertiliser for the brain,” BDNF supports the growth and survival of neurons. It’s strongly associated with better mood, sharper thinking and lower risk of depression. Exercise, particularly resistance and high-intensity work has been shown to increase BDNF levels, giving the brain a biochemical boost that may help explain those post-workout mood improvements.
Then there are myokines, hormone-like molecules released by muscles when they contract. One of the most well-studied myokines is irisin, which has been linked to anti-inflammatory effects and even brain health. These myokines don’t just work locally, they travel throughout the body, potentially influencing everything from fat metabolism to neuroplasticity.
Inflammation is another big one. Chronic low-grade inflammation is thought to play a role in mood disorders, especially depression. Resistance training has been shown to modulate inflammatory markers, reducing pro-inflammatory cytokines like TNF-α and IL-6, outside of the acute post-exercise window, and promoting a more balanced immune environment.
And then there’s the gut barrier itself. As discussed earlier, resistance training appears to reduce intestinal permeability, potentially by supporting the expression of tight junction proteins and mucin production. That means fewer bacterial toxins like LPS escaping into the bloodstream, reducing immune activation and, in theory, the inflammatory signals that can affect the brain.
It’s likely that these effects are working together, rather than in isolation. The muscle signals the brain, the gut communicates with the immune system and everything feeds back into mood, energy and motivation.
In short, resistance training isn’t just changing bodies, it’s changing biochemistry. And that’s where the real magic might be happening.
Practical Application
So what can we do with this information?
First, be aware that resistance training isn’t just a prescription for strength, it’s a potential tool for mental wellbeing. While we must stay within scope, as we’re not counsellors or therapists, we can still talk to clients about how training might help with stress, energy levels or even low mood. You might say something like:
“There’s some interesting research showing that resistance training can help with mood and even support gut health. Have you noticed any changes in how you’re feeling since starting your programme?”
You can also use simple tracking tools like asking clients to rate their mood before and after a session, to make the benefits more tangible over time.
It’s also worth noting that the Dow study used a remote delivery model. The training was done via an app and participants submitted videos for feedback. That’s encouraging for any of us working with online clients as it shows that mood and gut health benefits aren’t limited to in-person PT sessions. They can be achieved with thoughtful programming and regular contact, even through a screen.
Remote & Real-World Ready
The convenience of remote coaching, paired with personalised support, makes these benefits more accessible than ever. You don’t need a fancy studio or endless equipment. In fact, the Dow study deliberately chose low-skill, accessible exercises using dumbbells and cables as it is precisely the kind of setup many clients have at home or in commercial gyms.
What matters more than the tools is the structure, progression, and consistency of the programme. Over 8 weeks, participants trained just three times a week and the average session lasted around 45–60 minutes. That’s a realistic ask for most clients and it yielded measurable improvements in both physiological and psychological health.
A New Kind of Strength
/We often focus on helping clients get stronger, leaner, or more mobile. And that’s important. But this growing body of research reminds us that the benefits of resistance training reach much further.
We’re not just guiding people through sets and reps. We might be helping them sleep better, feel more balanced, manage stress, and support their gut-brain connection. Resistance training isn’t a cure-all, but it’s a powerful, accessible intervention with benefits that go far beyond the barbell.
Next time a client says, “I just feel better when I train,” you’ll know there’s some solid science behind that feeling.
References
- Dow, E., Hernandez, M. I., & Johnston, C. S. (2025). Eight weeks of resistance exercise improves mood state and intestinal permeability in healthy adults: A randomized controlled trial. Physiological Reports, 13, e70219. Click here to review the full research article.
- Gordon, B. R., et al. (2018). Association of efficacy of resistance exercise training with depressive symptoms: Meta-analysis and meta-regression analysis of randomized clinical trials. JAMA Psychiatry, 75(6), 566–576. Click here to review the full research article.
- Moore, J. H., et al. (2022). Exploring the effects of six weeks of resistance training on the fecal microbiome of older adult males: Secondary analysis of a peanut protein supplemented randomized controlled trial. Sports, 10(5), 65. Click here to review the full research article.
- Broadhouse, K. M., et al. (2020). Hippocampal plasticity underpins long-term cognitive gains from resistance exercise in MCI. NeuroImage: Clinical, 25, 102182. Click here to review the full research article.
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