BLUF
Infrared saunas (IR saunas) are increasingly popular in athletic recovery protocols. Unlike traditional saunas, IR saunas use infrared light to penetrate deeper into tissues, which may enhance muscle relaxation, blood flow, and recovery. The articles reviewed show that an IR sauna session at 110-115 degrees Fahrenheit immediately post-training leads to a ~20% greater reduction in muscle soreness and 42-60% improved neurological recovery after high-intensity strength or endurance training compared to the non-sauna control groups. Based on these findings, IR Sauna can be a very effective tool in recovery and follow-up training after intense training.
Strength Training Recovery
Training Protocols
The strength training protocol consisted of the following in a single session.
- Back Squats + Vertical Jump: 3 sets of 3 repetitions at 90-95% 1RM for back squats, paired with 3 Vertical Jumps. Rest: 1 minute between exercises, 3 minutes between sets.
- Nordic Hamstring Curls + Standing Long Jumps: 3 sets of 5 reps for Nordic curls and 3 standing long jumps. Rest: 1 minute between exercises, 3 minutes between sets.
- Leg Press + Box Jumps: 3 sets of 3 reps for leg press at 90-95% 1RM, paired with 1 box jump. Rest: 1 minute between exercises, 3 minutes between sets.
Sauna vs. Control Group Protocols:
- Infrared Sauna (IRS): Participants sat in an infrared sauna for 30 minutes after training, at 43°C (109°F) with 21% humidity for 20 minutes.
- Control (Passive Recovery): Participants engaged in passive recovery by sitting at room temperature (20°C or 68°F) for the same duration.
Testing Protocols
The testing protocols below measured neurological and muscle soreness indicators pre and post training.
Vertical Jump Testing Protocol – Measure neuromuscular performance and assess explosive lower-body power recovery after training and recovery sessions.
- Procedure:
- Three Vertical Jump Trials: Each participant performed three jumps per testing session.
- Hand Position: Participants placed their hands on their hips to prevent the use of arm swing, ensuring that the power generated came solely from the lower body.
- Rest Interval: A short rest was given between each jump to allow partial recovery and ensure consistency across the trials.
- Measurement and Analysis:
- Highest Jump Recorded: The highest jump from the three trials was taken as the final vertical jump score for each session.
- Timing of Measurements: Jump testing occurred at three time points:
- Baseline – Before the training session.
- Immediately Post-Recovery – After either the IRS or passive recovery session.
- 14 Hours Post-Recovery – To assess the impact of the recovery method on performance maintenance.
Muscle Soreness Testing Protocol – Assess subjective muscle soreness as a marker of recovery and muscle discomfort following the strength training session and recovery interventions.
- Measurement Tool:
- A 10-point Likert scale was used, where participants self-reported their muscle soreness levels. 0 = No Soreness, while 10 = Extreme Soreness
- Procedure:
- Self-Reported Soreness: Participants rated their soreness based on how they felt in the primary muscle groups targeted during the training session (e.g., legs, glutes, lower back).
- Timing of Measurements: Muscle soreness assessments were conducted at two key time points:
- Immediately Post-Recovery – Right after the infrared sauna or passive recovery session.
- 14 Hours Post-Recovery – To capture lingering muscle soreness and evaluate the effectiveness of each recovery method.
Recovery Results
Neuromuscular Recovery
- Control Group (Passive Recovery):
- Baseline: 13.39 inches (initial measurement).
- Immediately Post-Recovery: 12.72 inches (5.0% decrease from baseline).
- 14 Hours Post-Recovery: 12.40 inches (7.4% decrease from baseline).
- Sauna Group (Infrared Sauna Recovery):
- Baseline: 13.46 inches.
- Immediately Post-Recovery: 13.19 inches (2.0% decrease from baseline).
- 14 Hours Post-Recovery: 13.07 inches (2.9% decrease from baseline).
Muscle Soreness
- Control Group (Passive Recovery):
- Immediately Post-Recovery: 5.2 (baseline for soreness immediately post-recovery).
- 14 Hours Post-Recovery: 4.8 (7.7% decrease in soreness).
- Sauna Group (Infrared Sauna Recovery):
- Immediately Post-Recovery: 4.3 (baseline for soreness immediately post-recovery).
- 14 Hours Post-Recovery: 3.8 (11.6% decrease in soreness).
Endurance Training Recovery
Training Protocols Used
The endurance training protocol simulated the demands of a trail running race on a treadmill, with specific intervals designed to induce muscle damage, as follows:
Simulated Trail Run:
- Duration: 48 minutes, broken into five blocks.
- Interval Structure:
- 6 minutes on a flat surface (0% incline) to establish a steady running pace.
- 3 minutes uphill at a +10% incline.
- 3 minutes downhill at a 15% incline.
- Intensity: The running speed was adjusted for each interval based on incline to mimic real trail conditions. Uphill sections were at approximately 80% of maximal aerobic capacity, with downhill sections targeting high eccentric load to induce muscle damage.
Sauna vs. Control Group Protocols
- Infrared Sauna (IRS):
- Runners used a far-infrared sauna for 30 minutes at a temperature of 45°C (113°F) immediately post-run.
- This setting aimed to enhance blood flow and reduce soreness by promoting warmth-induced vasodilation.
- Control Group (Passive Recovery):
- Runners underwent passive recovery, seated comfortably at room temperature (20°C or 68°F) for the same duration.
Testing Protocols
Testing was conducted to assess muscle strength, soreness, and perceived fatigue at multiple time points following the endurance training session.
- Maximal Isometric Muscle Strength Testing:
- Objective: To measure muscle strength recovery post-exercise.
- Procedure: Runners performed maximal voluntary contractions (MVC) of the knee extensors at a 70° knee angle using an isokinetic ergometer.
- Measurement Timing: Strength was assessed before exercise, immediately post-run, then again 1 hour, 24 hours, and 48 hours after recovery.
- Muscle Soreness and Perceived Fatigue Testing:
- Objective: To evaluate muscle soreness and fatigue as markers of recovery.
- Measurement Tool: A computerized 100-point visual analog scale was used to rate soreness and fatigue (0 = no soreness/fatigue, 100 = extreme).
- Timing of Measurements: Soreness and fatigue were recorded immediately post-run, 1 hour, 24 hours, and 48 hours post-recovery.
Recovery Results
Maximal Isometric Muscle Strength Recovery
- Control Group (Passive Recovery):
- Immediately Post-Run: MVC showed a 29.6% decrease from baseline.
- 24 Hours Post-Recovery: MVC remained reduced by 22%.
- 48 Hours Post-Recovery: MVC showed a 20.8% decrease from baseline, indicating incomplete recovery.
- Infrared Sauna (IRS):
- Immediately Post-Run: MVC showed a 29.6% decrease from baseline.
- 24 Hours Post-Recovery: MVC improved to a reduction of 18% from baseline, showing faster recovery than passive.
- 48 Hours Post-Recovery: MVC returned closer to baseline, with only a 12% reduction, indicating enhanced strength recovery.
Muscle Soreness
- Control Group (Passive Recovery):
- Immediately Post-Run: Soreness scores averaged 61 on the 100-point scale.
- 24 Hours Post-Recovery: Soreness scores reduced slightly to 53 (a 13% decrease).
- 48 Hours Post-Recovery: Scores were 49, a 20% reduction from immediate post-run soreness.
- Infrared Sauna (IRS):
- Immediately Post-Run: Soreness scores averaged 61 on the 100-point scale.
- 24 Hours Post-Recovery: Soreness reduced significantly to 45 (a 26% decrease).
- 48 Hours Post-Recovery: Scores further decreased to 39, a 36% reduction from immediate post-run soreness, indicating faster recovery.
Findings Summary and Recommendations
Muscle Soreness
These results indicate that IR sauna sessions led to a consistent ~20% greater reduction in muscle soreness for both strength and endurance protocols compared to passive recovery.
- Strength Training: 20.8% improvement with IR Sauna compared to control.
- Endurance Training: 20.4% improvement with IR Sauna compared to control.
Neurological Recovery
These results suggest that IR sauna sessions contributed to substantial improvements in neurological recovery, with up to 60.8% better retention of performance following strength training and 42.3% better retention following endurance training compared to passive recovery.
- Strength Training (CMJ Performance): 60.8% improvement in performance retention with IRS.
- Endurance Training (MVC Performance): 42.3% improvement in performance retention with IRS.
Guidelines for IR Sauna Use:
- Duration: 20–30 minutes per session after intense training sessions.
- Timing: Immediate post-exercise use is most beneficial, facilitating faster recovery before the next training.
Bibliography
- Mero, A., Tornberg, J., Mäntykoski, M., & Puurtinen, R. Effects of Far-Infrared Sauna Bathing on Recovery from Strength and Endurance Training Sessions in Men. SpringerPlus, 2015.
- Hausswirth, C., et al. Effects of Whole-Body Cryotherapy vs. Far-Infrared vs. Passive Modalities on Recovery from Exercise-Induced Muscle Damage in Highly-Trained Runners. PLoS One, 2011.
- Ahokas, E. K., et al. A Post-Exercise Infrared Sauna Session Improves Recovery of Neuromuscular Performance and Muscle Soreness After Resistance Exercise Training. Biology of Sport, 2023.