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Performance

Red light and exercise recovery

Near-infrared light applied directly to a specific muscle shortly before exercise has a reasonable set of trials in healthy volunteers reporting more repetitions to fatigue and lower markers of muscle damage. Whole-body panels are a different question, and the evidence there does not currently support a performance benefit. A 2025 review of five whole-body studies in 105 active people found none reporting improved fatigue or performance markers, though two reported better sleep. This is an honest early rather than a promising one.

Evidence so far
Early
Reading timeAbout 12 minutes

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Why this is being studied

Exercise recovery here means the soreness, fatigue and biochemical disturbance that follow hard training, and whether light exposure changes how quickly a body settles afterwards. The light that has been studied for muscle is near-infrared at roughly 780 to 950 nm, which reaches subcutaneous tissue and superficial muscle. The idea is that light absorbed by mitochondria in muscle under oxidative stress may support energy production and damp inflammatory signalling, though the trials that report this delivered far more energy to a small muscle than a whole-body session does.

Where the evidence stands

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The mechanism

What is going on, and why this might help

What is going on in exercised muscle

Hard training leaves muscle with microscopic damage, inflammatory signalling, oxidative stress and mitochondria that are temporarily working below par. Soreness over the following days reflects that process rather than lactic acid. Recovery is the tissue clearing debris, resolving the inflammation and rebuilding, and anything that claims to speed recovery is claiming to influence one of those steps.

What the light is absorbed by

Cytochrome c oxidase in muscle mitochondria absorbs red and near-infrared light. Where nitric oxide is sitting on that enzyme and slowing respiration, the model is that absorbed photons displace it, briefly raising oxygen consumption and ATP output. Nitric oxide released locally widens small vessels and increases blood flow to the muscle, and a low-level burst of reactive oxygen species acts as a signal that activates antioxidant and repair pathways rather than causing harm. This is the rationale for applying light before exercise rather than after: the intention is to prime the tissue.

The biphasic dose response

The muscle trials point to roughly 20 to 60 joules per muscle site, delivered by probe or cluster, with weaker effects outside that range. The same total energy can behave differently depending on whether it is delivered quickly at high intensity or slowly at low intensity. This is the single biggest reason to be careful about transferring muscle findings to a panel: the energy per site is not comparable.

How far the light actually goes

Near-infrared at 780 to 950 nm reaches subcutaneous tissue and superficial muscle, on the order of millimetres to a couple of centimetres. A quadriceps or a calf has muscle within that range; deeper muscle and anything behind bone does not. A whole-body panel at 15 to 30 centimetres delivers roughly 10 to 60 milliwatts per square centimetre spread across the body, which lands in the skin dose range and only at the shallow end of the tissue dose range. That is the physical reason the localised evidence has not carried over to panels.

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The studies

Every study is laid out the same way: what the researchers wanted to find out, who took part, what they actually did, what they found, why it might work and where the limits are. No jargon, and a link to the original if you want to read it yourself.

Each study is laid out the same way: what the researchers asked, who took part, what they did, what they found, why it might work, and where the limits are. The clinician layer at the end of each one carries the numbers.

Paper 1

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

Vanin et al. · Lasers in Medical Science · 2018 · Systematic review and meta-analysis of randomised trials in healthy volunteers

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What they asked

By the mid-2010s there were dozens of small trials shining light on muscle before or after exercise, with mixed results and no agreement on how much energy to use or when to apply it. This international group asked whether, pooled together, the trials show improved muscular performance and reduced fatigue in healthy people, and whether a dose window can be identified from the pattern of positive and negative results.

Who took part

The review covered randomised trials in healthy volunteers rather than people with an injury or illness, which is important because light appears to do more in stressed tissue than in tissue that is already working well. Participants were typically young and active, often recreational athletes, and the exercise tasks ranged from repeated knee extensions to cycling and running protocols designed to induce fatigue.

What they did

The authors searched the literature, pooled outcomes such as repetitions to fatigue, time to exhaustion, peak torque and blood markers of muscle damage including creatine kinase and lactate, and grouped trials by wavelength, energy per site and whether the light was applied before or after exercise. Each trial compared active light against a placebo device.

What they found

The review reported that near-infrared light applied to muscle before exercise increased repetitions to fatigue and reduced markers such as creatine kinase compared with placebo. The pattern of results suggested a dose window of roughly 20 to 60 joules per muscle site, with less effect above and below it. Application before exercise generally looked better supported than application afterwards.

What it means

This is the basis for the claim that light may support muscle performance, and it is a real signal. The catch for members is the delivery again: 20 to 60 joules concentrated on one muscle site, from a cluster probe held against the leg, is a different proposition from a few minutes standing in front of a panel. Nothing here describes a whole-body session.

Limits

Most of the pooled trials were small and conducted in laboratory conditions with tasks chosen to be sensitive to change rather than to resemble training. Healthy young volunteers have the least room to improve, which cuts both ways. Publication bias is a real risk in a field of small positive studies. The dose window was inferred across trials rather than tested directly, and outcomes such as repetitions to fatigue do not necessarily translate into better training over a season.

Paper 2

A systematic review on whole-body photobiomodulation for exercise performance and recovery

Álvarez-Martínez and Borden · Lasers in Medical Science · 2025 · Systematic review of five studies of whole-body photobiomodulation, n=105 active people

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What they asked

Whole-body light panels and beds became widely available long before anyone had tested them. This review asked the direct question: across every published study of whole-body photobiomodulation in active people, is there evidence of improved exercise performance, reduced fatigue or better recovery markers.

Who took part

Only five studies met the criteria, covering 105 active people in total. That number is the headline finding in itself: the entire published evidence base for whole-body panels and athletic performance is smaller than a single decent trial. Participants were physically active adults, and the studies varied in the panels used, the exposure times and the outcomes measured.

What they did

The reviewers searched the literature for studies using whole-body devices rather than localised probes, extracted performance and recovery outcomes such as power output, fatigue measures, biomarkers of muscle damage and sleep or heart rate variability where reported, and described the quality and consistency of what they found.

What they found

None of the five studies reported a benefit for fatigue or for performance biomarkers. Two reported improvements in sleep. The reviewers described the evidence base as small, varied in method and insufficient to support performance claims for whole-body devices.

What it means

This is the most directly relevant evidence for anyone using a full-body panel for training, and it does not support a performance benefit. It is not the same as showing that panels do nothing, because five small studies cannot settle a question, but it does mean nobody should be told a session will improve their training. The sleep signal is the more interesting thread and belongs to a different learning path.

Limits

Five studies with 105 people between them is a thin base for any conclusion, positive or negative. The studies used different devices, doses, exposure times and outcome measures, so they cannot be pooled into a single number. Most were short, with no long training block. Absence of a reported effect in small studies is weak evidence of absence, and the honest reading is that whole-body panels for performance are untested rather than disproven.

Paper 3

Whole-body photobiomodulation improves post-exercise recovery but does not affect performance or physiological response during maximal anaerobic cycling

Forsey et al. · Lasers in Medical Science · 2023 · Randomised crossover trial, n=48

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What they asked

This American team asked whether twenty minutes in a whole-body photobiomodulation device before hard anaerobic cycling would change performance during the effort, the physiological response to it, or the state of the body the following morning.

Who took part

Forty-eight participants took part in a crossover design, meaning each person completed both the light condition and the control condition on separate occasions, with themselves as the comparison. That design is efficient and removes differences between individuals, which matters in performance testing where people vary enormously.

What they did

Participants received twenty minutes of whole-body light or a control condition, then performed repeated Wingate tests, a short maximal cycling protocol that is punishing and highly reproducible. The team measured power output across the repeats, physiological responses during the effort, and heart rate variability the following morning as a marker of autonomic recovery.

What they found

Researchers found no difference in repeated Wingate power output and no change in the physiological responses measured during the effort. Next-morning heart rate variability was higher after the light condition, which the authors interpreted as better post-exercise recovery.

What it means

This is a fair summary of where whole-body light currently sits for exercise: no measurable effect on the performance itself, and a recovery marker moving in a favourable direction. Heart rate variability is a real physiological measurement but it is also sensitive to sleep, stress and caffeine, so a single overnight difference is a thread worth following rather than a finding to build on.

Limits

A crossover trial of this type is hard to blind, since standing in a lit panel is obvious. Heart rate variability was a secondary outcome and one of several measures taken, which raises the chance of a difference appearing by chance. A single session before a single test session says nothing about weeks of training. The study measured anaerobic cycling specifically, which is only one kind of demand.