Red Light Therapy, Saunas, Cold Plunges, and Grounding: What’s Real and What’s Hype
Posted inTraining & Conditioning

Red Light Therapy, Saunas, Cold Plunges, and Grounding: What’s Real and What’s Hype

The information in this article is for educational purposes only and is not intended as medical advice. Always consult a licensed healthcare provider before starting any new health protocol.

Every biohacker on the internet has the same morning routine. Wake up. Drink sea salt water. Get morning sunlight. Hit the cold plunge. Sit in the sauna. Stand on the grass barefoot. Sit in front of a red light panel. Post it all on Instagram.

Some of these practices have decades of research behind them. Some have almost none. And the line between “evidence-based protocol” and “expensive trend” is something nobody pushing these products wants you to think too hard about.

Here’s what the science actually says about each one — no sponsorship deals, no affiliate links, no agenda.

Cold Plunges

What it is: Deliberate immersion in cold water — typically 38-55°F — for 1-5 minutes. Ice baths, cold plunge tubs, cold showers, or just a chest freezer full of water in your garage.

The claimed benefits: Increased dopamine, reduced inflammation, faster recovery, improved mood, fat loss through brown fat activation, immune system boost, mental toughness.

What the research actually says:

The dopamine claim is real — and it’s the strongest argument for cold exposure. A frequently cited study showed that cold water immersion at 57°F increased dopamine levels by approximately 250% and norepinephrine by 530%. Those levels stayed elevated for several hours. That’s a significant neurochemical response — bigger than what most supplements produce. This is why people describe feeling alert, focused, and elevated after a cold plunge. It’s not placebo. It’s measurable brain chemistry.

The inflammation and recovery claims are more complicated. Cold water does reduce inflammation — that’s basic biology. But for athletes, that’s not always desirable. Post-exercise inflammation is part of the adaptation process. Your muscles need that inflammatory response to rebuild stronger. Several studies have shown that cold water immersion immediately after strength training can actually blunt muscle growth over time. The current thinking among sports scientists is that cold exposure is best used on rest days or well after training — not as a post-workout recovery tool.

The fat loss claims center on brown fat activation. Cold exposure does activate brown adipose tissue, which burns calories to generate heat. But the actual caloric expenditure from this process is modest — we’re talking maybe an extra 100-200 calories, not a fat loss transformation. It’s a real mechanism but not a meaningful weight loss strategy on its own.

The immune system research is mixed. Some studies show positive effects on immune markers. Others show no significant difference. Not enough to make a definitive claim.

The honest take: The dopamine and mood benefits are legitimate and well-supported. If you do a cold plunge and feel incredible afterward, that’s real neurochemistry, not just toughness or placebo. For recovery, timing matters — keep it away from your strength training sessions. As a fat loss tool, it’s marginal at best. The mental toughness component — doing something uncomfortable deliberately — has value that’s harder to quantify but real.

Cost: A dedicated cold plunge tub (Plunge, Cold Stoic, etc.) runs $4,000-8,000. A chest freezer from Home Depot costs $200-400 and does the same thing with less Instagram appeal. A cold shower costs nothing.

Saunas

What it is: Deliberate heat exposure in either a traditional sauna (dry heat, 150-195°F) or an infrared sauna (lower temperature, 120-150°F, using infrared light to heat the body directly).

The claimed benefits: Cardiovascular health, longevity, detoxification, muscle recovery, improved skin, stress reduction, growth hormone release.

What the research actually says:

The cardiovascular research on saunas is strong — and it’s the most compelling reason to use one. A large Finnish study that followed over 2,300 men for 20+ years found that those who used a sauna 4-7 times per week had a 40% lower risk of all-cause mortality compared to those who used it once per week. They also had significantly lower rates of cardiovascular disease, stroke, and sudden cardiac death. That’s a massive dataset with a massive effect size.

The mechanism is straightforward — heat stress increases heart rate, improves blood vessel function, and activates heat shock proteins that help maintain cellular health. Your heart rate in a sauna can reach 120-150 BPM, which is comparable to moderate exercise. Some researchers describe sauna use as “cardiovascular exercise for people who can’t exercise” — though it’s beneficial for people who already exercise too.

Growth hormone claims are real but context-dependent. Sauna use can temporarily spike growth hormone, but the magnitude depends on temperature, duration, and frequency. One study showed a 16-fold increase in growth hormone after two 20-minute sauna sessions at 176°F. That sounds dramatic, but growth hormone spikes are temporary and it’s unclear how much that translates to actual muscle growth or fat loss compared to what exercise produces.

The “detoxification through sweat” claim is largely overstated. You do excrete some heavy metals and environmental toxins through sweat, but the quantities are small. Your liver and kidneys handle the vast majority of detoxification. Sweating is not a meaningful detox strategy. That said, it feels good, and the relaxation benefits are real.

The recovery benefits are moderate. Heat increases blood flow to muscles, which can help with soreness and stiffness. It’s a reasonable recovery tool, particularly for joint stiffness and general muscle tension.

Traditional vs infrared: Traditional saunas have more research behind them — the Finnish studies used traditional dry saunas. Infrared saunas operate at lower temperatures and heat the body more directly. They’re more comfortable for people who can’t handle extreme heat, and they’re easier to install at home. The research on infrared specifically is growing but less extensive than traditional sauna research.

The honest take: Saunas have the strongest evidence base of anything on this list. The cardiovascular and longevity data from Finland is hard to argue with. If you have access to a sauna and you’re not using it, you’re leaving a significant health tool on the table. The optimal protocol based on the research: 15-20 minutes, 3-7 times per week, at 175°F or higher.

Cost: Gym membership with a sauna is the cheapest option. A home infrared sauna runs $1,500-5,000. A traditional barrel sauna for your backyard runs $3,000-8,000. Many gyms, including Planet Fitness, have saunas or red light therapy beds available with membership.

Red Light Therapy

What it is: Exposure to low-wavelength red light (630-670nm) and near-infrared light (810-850nm) through LED panels, beds, or handheld devices. Also called photobiomodulation or low-level light therapy (LLLT).

The claimed benefits: Skin health, wound healing, reduced inflammation, muscle recovery, joint pain relief, testosterone production, hair growth, collagen production, mitochondrial function.

What the research actually says:

Red light therapy has a legitimate body of research — but it’s not as clean-cut as the marketing suggests.

The wound healing and skin health evidence is the strongest. Multiple studies show that red and near-infrared light promotes collagen production, reduces wrinkles, improves skin tone, and accelerates wound healing. Dermatologists and physical therapists have used photobiomodulation for years. This isn’t fringe — it’s established in clinical settings.

The joint pain and inflammation evidence is moderate. Several studies show benefits for osteoarthritis, tendonitis, and general joint pain. The mechanism — light energy absorbed by mitochondria, increasing ATP production and reducing oxidative stress — is biologically plausible and supported by cell and animal studies.

The muscle recovery evidence is promising but inconsistent. Some studies show reduced delayed onset muscle soreness (DOMS) and faster recovery. Others show no significant benefit. The dose, timing, and wavelength matter, and standardization across studies is poor.

The testosterone claim comes primarily from one study showing that red light applied directly to the testes increased testosterone levels. It’s a single study with a small sample size. The biohacker community ran with it. The evidence is too thin to make confident claims.

The hair growth evidence is moderate — FDA-cleared red light devices for hair growth exist and have clinical data supporting them. It’s not going to regrow a fully bald head, but for thinning hair, the evidence is reasonable.

The honest take: Red light therapy works for some things — particularly skin health, wound healing, and joint pain. The hype has outpaced the evidence for everything else. The big challenge is dose — most studies that show positive results use clinical-grade devices at specific wavelengths, distances, and exposure times. Whether a consumer panel you bought online delivers the same dose is an open question. If you have access to red light therapy at your gym, use it. If you’re thinking about spending $1,000+ on a home panel, understand that the evidence for the claims you care about most might not be as strong as the marketing implies.

Cost: Small handheld devices run $50-200. Full-body panels (Joovv, Mito Red Light, PlatinumLED) run $500-2,500. Red light therapy beds at gyms and spas are included with membership or cost $15-40 per session.

Grounding (Earthing)

What it is: Walking barefoot on natural surfaces — grass, dirt, sand, or stone — or using grounding mats, sheets, or patches indoors. The concept is that direct contact with the earth’s surface allows your body to absorb negatively charged electrons, which neutralize free radicals and reduce inflammation.

The claimed benefits: Reduced inflammation, improved sleep, reduced cortisol, improved blood flow, reduced pain, faster recovery.

What the research actually says:

This is where the evidence gets thin. The grounding research consists of a small number of studies, most with small sample sizes and methodological limitations. A few studies have shown:

  • Reduced blood viscosity (thinner blood, better flow) after grounding
  • Changes in cortisol patterns that suggest improved sleep-wake cycles
  • Reduced markers of inflammation
  • Self-reported improvements in pain, stress, and sleep quality

The biological mechanism — electron transfer from the earth’s surface — is plausible from a physics perspective. The earth’s surface carries a negative electrical charge, and direct contact could theoretically influence the body’s electrical environment.

But the research is far from conclusive. The studies are small. Many rely on self-reported outcomes. There’s limited blinding (it’s hard to not know whether you’re standing barefoot on grass). The grounding product industry — mats, sheets, patches, bands — has grown far faster than the evidence supporting it.

The honest take: Walking barefoot outside feels good. There may be some biological benefit to direct earth contact, but the evidence is early and not strong enough to justify the definitive health claims being made. The products — grounding mats, earthing sheets, grounding patches — are a hard sell given the current evidence base.

Here’s the thing, though — walking outside barefoot in the morning sunlight for 10-15 minutes is free, it gets you sunlight (proven benefits), fresh air, and movement. Whether the “grounding” part adds a meaningful biological benefit on top of those other factors is unclear. But you’re not losing anything by doing it.

Cost: Walking barefoot is free. Grounding mats run $30-100. Grounding sheets run $100-300. If you’re going to spend money, spend it on a sauna or a cold plunge — the evidence is significantly stronger.

The Hierarchy of Evidence

If you’re going to invest time and money in recovery and wellness practices beyond your training and nutrition, here’s where the evidence actually stacks up:

Strong evidence — do this:

  • Sauna (3-7x per week, 15-20 minutes)
  • Cold exposure for mood and mental clarity (on rest days or away from training)

Moderate evidence — worth trying:

  • Red light therapy for skin, joints, and wound healing
  • Cold exposure for general recovery (with timing considerations)

Weak evidence — maybe, maybe not:

  • Grounding/earthing
  • Red light therapy for testosterone, muscle growth, or fat loss
  • Cold exposure as a primary fat loss tool

The free version: Walk barefoot outside in the morning sunlight for 15 minutes. Take a cold shower at the end of your regular shower. Use the sauna at your gym after training. You’ve just done four biohacks for $0.

The Bottom Line

The wellness industry wants you to believe that you need a $6,000 cold plunge, a $2,000 red light panel, a $5,000 sauna, and a grounding mat to optimize your health. You don’t.

What you need is to train consistently, eat real food, sleep enough, take your basic supplements, and get bloodwork done once or twice a year. After that foundation is solid — and only after — these tools can add incremental benefits.

The sauna has the strongest evidence. Use one if you can. Cold exposure is real for mood and dopamine. Red light therapy works for skin and joints. Grounding is mostly free and mostly unproven.

Don’t let the biohacking industry convince you that buying equipment is a substitute for doing the work.

The Biohacker Effect: Brecka, Huberman, and the Protocols Everyone Is Following
How Sleep Affects Your Gains More Than Any Supplement
Supplements 101: What You Actually Need and What’s a Waste of Money

Products and Brands Mentioned:

  • Plunge — Dedicated cold plunge tubs with temperature control.
  • Cold Stoic — Cold plunge tubs.
  • Joovv — Full-body red light therapy panels.
  • Mito Red Light — Red light therapy panels at lower price points than Joovv.
  • PlatinumLED — Red light therapy devices.
  • Restore Hyper Wellness — Wellness chain with saunas, cryotherapy, red light, and more.