Purpose: This study investigated effects of far-infrared sauna (FIRS) bathing on recovery from strength training and endurance training sessions, but also possible differences between FIRS and traditional (TRAD) Finnish sauna bathing.
Methods: Ten healthy physically active male volunteers had on various days either a 60 min hypertrophic strength training session (STS) or a 34-40 min maximal endurance training session (ETS), which was following by 30 min bathing in special FIRS sauna at temperature of 35-50°C and humidity of 25-35%. After the sauna, subjects sat for 30 min at room temperature (21°C and 25-30% humidity). In comparison, 30 min of TRAD took place at 35-50°C and in 60-70% humidity. Performance tests included maximal isometric bench press and leg press, counter movement jump (CMJ) and maximal oxygen uptake on a treadmill.
Results: After STS, there were decreases in maximal isometric bench press (p < 0.001), maximal isometric leg press (p < 0.001), CMJ (p < 0.001) and pH (p < 0.001), but increases in heart rate (p < 0.001) and lactate concentration (p < 0.001) as expected. During recovery there were no differences in any variables between FIRS and no sauna bathing (NO SAUNA). Maximal ETS increased oxygen uptake (p < 0.001), heart rate (p < 0.001), lactate concentration (p < 0.001) and decreased pH (p < 0.001) as expected. During recovery at 30 min, CMJ was significantly (p < 0.05) higher (0.34 ± 0.09 m) after FIRS bathing than after sitting with NO SAUNA (0.32 ± 0.0 m). After sauna heart rate was higher (p < 0.05) in TRAD (92 ± 13 beats/min) than in FIRS (71 ± 7 beats/min).
Conclusion: In conclusion, deep penetration of infrared heat (approximately 3-4 cm into fat tissue and neuromuscular system) with mild temperature (35-50°C), and light humidity (25-35%) during FIRS bathing appears favorable for the neuromuscular system to recover from maximal endurance performance. FIRS bathing is a very light loading for the body and provides a comfortable and relaxing experience.
Keywords: Exercise; Far-infrared; Neuromuscular; Performance; Sauna.