Abstract
Sauna bathing is a recovery strategy driven by increased thermal load and can be used before or after exercise, highlighting the need to understand how thermal load relates to exercise timing. However, accompanyingcardiovascular load may compromise physiological benefits, warranting investigation into sauna timing to identify an optimal balance between thermal and cardiovascular load. PURPOSE: Examine differences in thermal and cardiovascular load across different timing strategies of sauna bathing relative to exercise. METHODS: 8 recreationally active participants (males: n = 7; females; n = 1; age: 29 ± 5 years; body mass: 72.5 ± 7.1 kg; height: 174.3 ± 7.7 cm) performed functional fatiguing exercise in a randomized, counterbalanced order, and were assigned to three protocol groups: post-exercise sauna (PostSB), pre-exercise sauna (PreSB), and no sauna (NoSB). Sauna bathing consisted of sitting in a portable sauna pod (ambient temperature: 44.3 ± 0.8℃; relative humidity: 95.0 ± 1.4%) for 45 min, with 5 min of rest outside the pod following every 15 min of exposure, while core temperature (Tc) and heart rate (HR) were monitored at 5-min intervals. The fatiguing exercise protocol was performed before or after sauna bathing and consisted of 15-min downhill running, drop jumps (3 sets x 20 reps), and eccentric-focused push-ups and pull-ups (3 sec eccentrics; 3 sets x 10 reps), with Tc and HR being monitored throughout the entire duration. Thermal and cardiovascular load were quantified as the time-integrated Tc and HR responses (area under the curve [AUC] from zero) across sauna bathing and exercise periods. Differences in thermal and cardiovascular load were analyzed using linear mixed-effects models with condition included as a fixed effect and subject as a random effect, and effects reported as estimated marginal means and 95% confidence intervals. Condition-specific linear mixed-effects models were used to quantify population-level associations between total Tc and total HR. RESULTS: A significant main effect of condition on Tc and HR (p<0.001) was revealed. For Tc, PreSB (3,211 [3,192;3,230] a.u.) and PostSB (3,198 [3,179;3,217] a.u.) resulted in greater thermal load compared to NoSB (2,976 [2,957;2,996] a.u.; p < 0.001), with no significant difference between PreSB and PostSB (p = 0.345). HR observed a similar response, with PreSB (11,177 [9,980;12,375] a.u.) and PostSB (10,719 [9,521;11,916] a.u.) demonstrating greater cardiovascular load compared to NoSB (9460 [8,262; 10,657] a.u.; p < 0.01), and no difference between PreSB and PostSB (p=0.381). Across all conditions, thermal load was statistically correlated with cardiovascular load (β=6.59±1.30, p<0.001). Condition-specific analyses revealed significant correlations between thermal and cardiovascular load during NoSB (r=0.74, p=0.035) and PreSB (r=0.63, p=0.092), but not PostSB (r=0.53, p=0.173). CONCLUSION: Sauna bathing increased thermal and cardiovascular load when combined with exercise, independent of timing, while exercise may increase inter-individual variability in Tc and HR responses during subsequent sauna exposure.
Recommended Citation
Richardson, Isabel J.; Keefe, Marcos S.; McCollum, Tyler B.; Brojanac, Alexandra P.; and Sekiguchi, Yasuki
(2026)
"Accumlated Thermal and Cardiovascular Load are Unaffected by Sauna Bathing Timing Relative to Exercise,"
International Journal of Exercise Science: Conference Proceedings: Vol. 2:
Iss.
18, Article 44.
Available at:
https://digitalcommons.wku.edu/ijesab/vol2/iss18/44