Red Light Therapy Before or After Workout | LightTherapy.no
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Red Light Therapy Before or After Workout: Which Works Better?
I get asked this one a lot. Often from people who already know red light helps with recovery and now want to know whether they should also be using it before training. The short answer is that pre-workout and post-workout use are two different applications of the same tool, with different mechanisms, different protocols, and different effects. Most people who use both consistently see more out of it than people who only use one. But the pre-workout question is the one with weaker awareness, and it's probably the more interesting one in terms of actual performance changes.
I'll walk you through both. What I do, what the research shows, what makes sense for different goals.
Red light therapy before a workout primes your muscles by pre-loading mitochondrial energy production, increasing local blood flow, and reducing perceived exertion during the session itself. Red light therapy after a workout accelerates recovery by reducing oxidative stress, calming inflammation, and supporting tissue repair. The research supports both applications, with pre-workout sessions of 5-15 minutes typically done 0-30 minutes before training, and post-workout sessions in the same time range within the first couple of hours after the session ends.
My Own Use, Briefly
I still train. Not the way I did as a personal trainer, but consistently. And I use red light around training because I notice the difference when I do versus when I don't.
Pre-workout, for me, is mainly about feeling like the engine is warm before I start. It's a subtle thing, not dramatic, but I notice better output in the first few sets when I've done five or ten minutes on the legs and lower back before training. Post-workout is more obvious because the muscle soreness over the following 24 to 48 hours is noticeably less when I do it consistently. Especially as I've got older, with the osteoarthritis stuff in the background, that recovery edge matters more than it used to.
So I do both. Different protocols, different reasons, both worth their place. Let me explain what each one actually does at the tissue level.
Pre-Workout: What's Actually Happening
The pre-workout application is the more interesting one mechanistically, partly because it goes against what most people assume red light is for. Most people associate red light therapy with recovery. The pre-workout effect is performance, not recovery.
Here's the biology. When you light up a muscle with red and near-infrared wavelengths before training, you're causing several things to happen in the tissue before you put load on it. ATP production in the mitochondria ramps up. Cytochrome c oxidase absorbs the photons, the electron transport chain accelerates, and the cells are essentially primed with more available energy than they would have started the session with.
At the same time, local blood flow increases through the nitric oxide pathway. The cells lining your blood vessels release nitric oxide in response to near-infrared light, the vessels relax, more blood gets into the muscle. You're essentially showing up to the session with a muscle that's already warmed up at the vascular level before you've moved a muscle yourself.
The downstream effects on actual performance have been studied across a range of exercise types. A 2016 systematic review by Vanin and colleagues, published in Lasers in Medical Science, pooled the data on pre-exercise photobiomodulation and found consistent reductions in muscle fatigue and improvements in muscle performance markers across studies. You can find it here.
More recent work has continued to support the picture. Researchers including Ferraresi, Hamblin, and others have published on the pre-conditioning effect of light on muscle, with consistent findings around delayed onset of fatigue, improved peak performance, and reduced muscle damage markers post-exercise when light is applied before the session rather than after.
The effect sizes aren't dramatic. We're not talking about turning a normal training session into a record-breaking one. We're talking about a few percent improvement in fatigue resistance, peak output, time to exhaustion in protocols where these things are measured. For a competitive athlete those few percent matter. For someone training for general fitness or health, they show up as the session feeling slightly easier and the recovery being slightly better.
Post-Workout: The More Familiar Story
This is the one most people already know about. After a hard training session, your muscles have accumulated metabolic byproducts, undergone microtrauma, generated reactive oxygen species, triggered an inflammatory response. All of that is normal and necessary. It's how training works. The signal of damage is part of what drives adaptation.
But that signal can also accumulate to the point where it's slowing you down between sessions, making sleep worse, leaving you sore for days, blunting the next session. This is where post-workout red light comes in.
The mechanism is roughly the opposite of what people assume. Red light doesn't suppress the adaptive signal entirely. What it does, based on the research, is reduce the excess oxidative damage and inflammation while allowing the underlying adaptive signaling to continue. You recover faster without losing the training effect.
A 2018 meta-analysis by Vanin and colleagues, again in Lasers in Medical Science, looked specifically at post-exercise photobiomodulation and found significant reductions in muscle soreness, faster recovery of muscle strength, and reduced markers of muscle damage in treated groups versus controls. Here.
For practical purposes, this is what people notice. Less DOMS, that classic 24-to-48-hour soreness after a hard session. Faster restoration of strength between training sessions. The ability to handle more training volume per week without breaking down.
If you're training seriously, this matters. If you're trying to balance training with the rest of your life and not waking up sore every morning, this also matters.
Which Do You Need More, And When
Right, so given that both work, what should you actually do?
If you only want to do one, I'd say it depends on the goal.
If you're a competitive athlete trying to extract a few percent more from training sessions, pre-workout is probably where the bigger leverage is. The performance enhancement during the session itself directly translates into more training stimulus, which over time becomes more adaptation.
If you're training for general fitness and health, and the bottleneck is recovery and feeling fresh between sessions, post-workout is probably the better single application. The soreness reduction and faster recovery between sessions is what you'll notice most.
If you can do both, do both. Different effects, different mechanisms, additive. Pre-workout is short, five to ten minutes, applied to the muscles you're about to work, done within 30 minutes of starting training. Post-workout is similar length, applied to the same muscles, ideally within the first couple of hours after finishing.
A note on dosing. Just like with everything else in this category, the biphasic dose response matters. Too little light, nothing happens. Right amount, you get the effects described above. Too much, you can actually blunt the performance or recovery benefits. So sessions in the five to fifteen minute range, at appropriate distance from the panel, are where you want to be. Sitting in front of a panel for an hour because you want maximum effect is the wrong move. It can do the opposite of what you're after.
What I Actually Hear From Customers
The customer pattern I see is roughly this. People who train regularly start using red light therapy initially for recovery, because that's the angle they've heard about. They use it post-workout for a few weeks, feel a real difference in soreness, and then come back asking whether it's also worth doing before training.
When they add the pre-workout use, the most common feedback is that sessions feel slightly easier and they hit their numbers more reliably. Nobody comes back saying it transformed their training. Some come back saying they didn't notice any difference. Most land somewhere in between. A useful tool that contributes to the overall package, not the secret weapon they were hoping for.
The other thing that comes up a lot is whether to use it on injury-prone areas before training as a kind of prehab. A runner with a history of Achilles trouble doing a few minutes on the Achilles before a long run. A lifter with a cranky shoulder doing pre-conditioning before a heavy upper body day. The logic makes sense. You're priming the tissue with cellular energy and improving local blood flow in an area that's known to give problems, and the customer feedback on this is generally positive. There isn't dedicated research on this specific application, but the underlying biology fits.
The Dose Problem Again
I'll bang on about this because it matters. The single biggest reason people don't get results from red light therapy around training is that the dose at the tissue is wrong. Either the panel is underpowered and they're getting tiny amounts of light at the muscle level, or the panel is fine but the distance and time are wrong for what they're trying to do, or the panel is fine but the device they were sold has specs that look impressive on paper and don't match what comes out of it in reality.
I get the messages from people who bought elsewhere, used the panel diligently around their training for two or three months, and felt nothing. Usually we work out fairly quickly what the actual delivered dose was likely to have been, and it was either too low or in some cases too high. Either way, the result they were after wasn't going to happen with what they had.
Message me if you want to think through your own setup. You don't need to have bought from me. I'd rather you got the protocol right with what you already own than have you give up because the first attempt didn't work. If we work out that what you have isn't capable of delivering useful doses to the muscles you're training, then we can talk about whether something more suitable makes sense. Often the existing panel still has a role for surface work or smaller areas, and a different device handles the deeper muscle work.
I test every panel I stock with a spectrometer before it goes on the site. I've sent things back when the measured output didn't match the claims. Not fun conversations with suppliers, but necessary ones. The longer version of why this industry's published specs are mostly fiction is here.
Practical Protocol: What I'd Actually Tell You
If you train three to five times a week and want to use red light therapy around your sessions, here's a sensible starting point.
Pre-workout: 5-10 minutes on the muscles you're about to train, within 30 minutes of starting the session. Close range, direct skin exposure where possible, no clothing in the way. For lower body sessions, the quads and posterior chain. For upper body, the shoulders, lats, chest, whatever the main targets are. For full-body sessions, prioritise the largest muscle groups you're training that day.
Post-workout: 10-15 minutes on the same muscles, within a few hours of finishing the session. Some people prefer to do it right after, some prefer to do it in the evening before bed if their session was in the morning. Both work. The window isn't tight.
If you're combining with stretching, mobility work, or sauna, fit the light sessions in alongside those rather than competing for time. Many people do their pre-workout light during their warm-up, and their post-workout light during their cool-down stretching.
Consistency matters more than intensity. A four-week trial of pre and post workout light, done consistently around every training session, will tell you more about whether it's useful for you than a sporadic three-month trial.
If you want to talk through what setup makes sense for your training, send me a message. I've helped a lot of athletes and recreational trainers think through this. You can also browse the red light therapy panel collection if you want to see what's available.
Where This Connects to Recovery More Broadly
If you've read the muscle recovery post, this is the same biology approached from a different angle. The recovery post is about what red light does after the damage is done. This post is about what it does to prepare for the damage and then clean it up afterward.
For a broader look at the research, the 2025 half-year research review covers muscle, joint, and tissue work across the year's notable studies.
Disclaimer: This article is for educational purposes only. It is not medical advice. If you have an injury, chronic condition, or specific training-related concern, consult a qualified healthcare or sports medicine professional before starting any new therapy.
Norwegian version of this article: https://lighttherapy.no/blogs/norsk/rodlysterapi-for-eller-etter-trening
Frequently Asked Questions
Should I use red light therapy before or after my workout?
Both work, and they do different things. Pre-workout use primes muscle performance by pre-loading mitochondrial energy production and improving local blood flow, with research showing reduced muscle fatigue and improved peak output during the session itself. Post-workout use speeds recovery by reducing oxidative stress and muscle damage markers, leading to less soreness and faster restoration of strength between sessions. If you can do both, do both. If you have to choose one, pre-workout favours athletes seeking performance, post-workout favours people whose main goal is recovery and consistency.
How long before a workout should I use red light therapy?
Most studies on pre-exercise photobiomodulation apply the light 0-30 minutes before the training session begins. Some research has tested longer pre-conditioning windows, but the strongest evidence is for application close to the session. A 5-10 minute exposure on the muscles you're about to train, done within half an hour of starting, hits the sweet spot for both timing and dose.
Will red light therapy reduce muscle soreness?
Yes, this is one of the better-supported effects of post-workout photobiomodulation. Multiple studies and meta-analyses show significant reductions in delayed onset muscle soreness (DOMS), faster recovery of muscle strength, and reduced markers of muscle damage in treated groups versus controls. The effect is most pronounced when light is applied within the first couple of hours after a session ends.
Kan jeg bruke rødlysterapi før trening?
Ja, forskningen støtter bruk av rødlysterapi før trening for å redusere muskeltretthet og forbedre ytelse under selve økten. Mekanismen er at lyset øker ATP-produksjonen i mitokondriene og bedrer lokal blodsirkulasjon i muskelvevet, slik at musklene er "ladet opp" før belastningen starter. Bruk typisk 5-10 minutter på musklene du skal trene, innen 30 minutter før økten begynner. Effekten er reell men moderat, og varierer fra person til person.
Does it matter if I use it on rest days?
For people training hard, daily red light therapy on rest days is fine and probably useful. The systemic effects on inflammation, mitochondrial function, and recovery don't switch off because you aren't training. Many athletes find that using red light therapy daily, regardless of whether they're training that day, smooths out their overall recovery and energy patterns better than only using it around sessions. The biphasic dose response still applies. Sessions of 10-20 minutes are plenty.
References
Vanin AA, Verhagen E, Barboza SD, et al. Photobiomodulation therapy for the improvement of muscular performance and reduction of muscular fatigue associated with exercise in healthy people: a systematic review and meta-analysis. Lasers in Medical Science. 2018. https://pubmed.ncbi.nlm.nih.gov/27718117/
Vanin AA, Miranda EF, Machado CS, et al. What is the best moment to apply phototherapy when associated to a strength training program? A randomized, double-blinded, placebo-controlled trial. Lasers in Medical Science. 2016. https://pubmed.ncbi.nlm.nih.gov/26795269/
Ferraresi C, Huang YY, Hamblin MR. Photobiomodulation in human muscle tissue: an advantage in sports performance? Journal of Biophotonics. 2016. https://pmc.ncbi.nlm.nih.gov/articles/PMC5167494/