You’ve probably seen the Instagram posts, runners training at altitude camps in Boulder or Flagstaff, bragging about their EPO gains and blood volume increases.
And you’ve probably thought: “That sounds great, but I can’t take three weeks off work to live at 7,000 feet.”
Here’s what most runners don’t realize: you might not need to.
Research by Scoon and colleagues [1] found that runners who added 30 minutes of post-exercise sauna bathing to their normal training improved their time to exhaustion by 32%, equivalent to cutting nearly 2% off their 5k time. That’s the difference between a 20:00 5k and a 19:36. The difference between hitting your Boston qualifier and missing it by two minutes.
The mechanism? Heat stress triggers the same EPO production and blood volume expansion that altitude training does, but you can do it at your local gym for $15 instead of spending $3,000 on an altitude camp.
That’s because strategic heat exposure creates physiological adaptations that are remarkably similar to altitude training, increased red blood cell production, expanded plasma volume, and improved oxygen delivery to working muscles.
For time-constrained adult runners (that’s most of us), this is game-changing news. You don’t need to disrupt your life, your job, or your family schedule to get performance gains that were previously only accessible to professionals.
Here’s what you need to know: the specific protocols that work, when to use sauna training in your race preparation, which workouts to pair it with, and the safety considerations you can’t ignore.
Why Altitude Training Works (And Why You Can’t Do It)
Athletes have relied on altitude training for decades because the science is straightforward: reduced oxygen availability at elevation triggers your kidneys to release erythropoietin (EPO).
EPO signals your bone marrow to produce more red blood cells, increasing your blood’s oxygen-carrying capacity.
But here’s the problem: altitude training requires 500+ hours of exposure above 2,100 meters to maximize hemoglobin increases.
That’s not a weekend trip to the mountains. That’s weeks of living at elevation.
Most adult runners balancing training with careers and families simply can’t make that work. Even “live high, train low” protocols require access to altitude houses or hypoxic chambers that cost thousands monthly.
The Sweat Connection: How Heat Mimics Altitude
When you sit in a sauna after your workout, something remarkable happens.
You sweat, a lot. And that sweat comes primarily from your blood plasma (the liquid part of your blood, separate from red blood cells).
As plasma volume decreases and you become strategically dehydrated, blood flow to your kidneys drops. This reduction in renal blood flow triggers the same response as altitude: EPO release.
But there’s more happening than just dehydration.
The landmark study by Scoon and colleagues [1] found that competitive male runners who completed 3 weeks of post-exercise sauna bathing increased plasma volume by 7.1% and red blood cell volume by 3.5%.
These weren’t recreational joggers. These were competitive athletes with sub-18 minute 5k times.
Let’s look at what this actually means for your running.
What Blood Volume Expansion Does For Your Performance
Think about your cardiovascular system like a water pump.
When there’s more water in the system, each pump stroke moves more fluid with less effort. More blood volume means every heartbeat delivers more oxygen to working muscles without your heart working harder.
The result? Lower heart rates at the same effort levels and improved VO2max.
Research by Kirby and colleagues [2] on middle-distance runners demonstrated approximately 8% improvement in VO2max and 4% improvement in running speed at lactate threshold after intermittent post-exercise sauna bathing.
Compare this to traditional altitude training, which requires 500 hours at elevation to maximize hemoglobin increases, while heat training can be completed in 10-20 sessions over 2-4 weeks.
That’s not a marginal difference. That’s accessible performance enhancement.
The Protocol That Actually Works
The research is remarkably consistent on what produces results (and what wastes your time).
Traditional saunas at 85-90°C (185-194°F) with low humidity appear optimal for triggering adaptations. Infrared saunas at lower temperatures can work, though you may need longer sessions.
Duration matters: 20-30 minutes per session is the evidence-based sweet spot.
Timing is critical. Enter the sauna within 30 minutes of completing your workout, this capitalizes on your already-elevated core temperature and maximizes the physiological stimulus.
Start with 3-4 sauna sessions per week, each following a moderate to hard training run (not your hardest workout, and definitely not your long run).
The first session will be challenging. That’s not surprising if you’ve never done heat training before. But your heat tolerance builds quickly, most runners notice significant improvement within 3-5 exposures.
The proven protocol: sauna 3-4 times weekly for three consecutive weeks, then take a complete break.
Here’s the controversial part that most articles won’t tell you: strategic dehydration enhances the EPO response.
The Scoon study [1] participants didn’t pound water during their sauna sessions. They allowed themselves to become dehydrated during the heat exposure, this controlled stress is part of what triggers the adaptation.
You can drink small amounts (up to 100ml) during a 30-minute session, but the goal is heat stress, not comfort. This creates the hormonal trigger you need without compromising safety.
When To Use It (And When To Skip It)
Start your sauna protocol 3-4 weeks before a goal race.
Peak benefits occur after approximately 12 sessions spread over 3 weeks. Then, and this is crucial, stop all sauna training 7-10 days before competition.
This taper allows your blood volume adaptations to stabilize and ensures you arrive race day feeling fresh, not fatigued.
But timing extends beyond the calendar. It’s also about which workouts you pair with heat exposure.
Use sauna after moderate to moderately-hard runs where you finish feeling strong, think tempo runs, threshold work, or steady-state efforts.
Skip the sauna after depletion workouts, long runs exceeding 90 minutes, or sessions already completed in hot conditions.
Unfortunately, the research reveals important limitations. A study [3] of swimmers showed that post-workout sauna impaired next-day performance after very hard sessions. After intensive exercise that leaves you depleted and dehydrated, sauna becomes an additional stressor that diverts recovery resources away from muscle repair.
The issue is that heat exposure increases blood flow to the skin for cooling rather than to muscles for recovery. When you’re already depleted, this trade-off works against you.
Listen to your body. If you’re dizzy, nauseous, or extremely fatigued, defer your heat session.
Safety First: What You Need To Know
Heat training isn’t appropriate for everyone.
If you have cardiovascular conditions, uncontrolled high blood pressure, or history of heat illness, this protocol isn’t for you. Pregnant women should not use post-exercise heat training, and anyone taking medications that affect sweating or thermoregulation must consult their physician first.
Proper hydration before entering the sauna is non-negotiable. Drink 500-750ml of fluid in the hour before your session.
Post-sauna, aggressive rehydration matters. Aim for electrolyte-rich fluids along with carbohydrates, research [4] suggests 1.2g of carbohydrate per kilogram of bodyweight each hour for the first 4 hours.
Exit immediately if you experience extreme dizziness, nausea, rapid heartbeat, or confusion. These are signs of heat exhaustion and require immediate cooling and rehydration.
But, we don’t want to be pushing through symptoms (despite how tough we are). Instead, we want to understand the signals our body is sending and respond appropriately.
Expected Results and Realistic Timelines
The Scoon study [1] demonstrated 1.9% improvement in 5k performance after just 3 weeks, participants increased their time to exhaustion at 5k pace by 32%.
For most runners, plasma volume expansion begins within 4-7 days. You’ll notice lower heart rates at given paces within 10-14 days. Peak adaptations occur around week 3.
Individual responses vary, but the research provides clear guidance: this protocol works for trained recreational runners, not just elites.
Your baseline heat tolerance affects initial adaptation speed, and runners with higher initial fitness levels may see smaller percentage gains. That’s not surprising if you’ve been training consistently for years.
Making It Work With Your Life
The beauty of post-exercise heat training is its efficiency.
You’re already at the gym or have just finished a home run. Adding 20-30 minutes of sauna doesn’t require separate training time or travel to an altitude camp.
Start by securing consistent sauna access, most gyms have them, community centers often do, and home units have become more affordable.
Schedule your first 3-week block during a base-building phase, not during race-specific training when every workout counts toward a specific adaptation.
Time it to end 3-4 weeks before your goal race, then stop completely 7-10 days out.
Monitor your recovery carefully during the first week. The added stress of heat exposure means you might need to reduce training volume by 10-15% initially. Watch your morning heart rate, if it stays elevated, you’re not recovering adequately.
The Accessible Performance Edge
While your competitors spend thousands on altitude houses or travel to elevation camps, you can achieve comparable adaptations with equipment that costs $10-20 per session at most gyms.
The research backs it: post-exercise sauna training triggers similar physiological adaptations to altitude, including EPO production, blood volume expansion, and improved oxygen delivery.
A 3-week protocol can deliver 2-3% performance improvements. For a runner targeting a 3:30 marathon, that’s over 6 minutes. For someone chasing a sub-20 5k, that’s 24 seconds.
The science is clear, the protocols are proven, and the barrier to entry is remarkably low.
Start with finding sauna access. Add sessions after moderate workouts. Build gradually. Stop before your race. Hydrate aggressively.
That’s the protocol. Now you have the knowledge to implement it correctly.
