Mid Sweden University

Background: Whole-body heat exposure, such as sauna bathing or hot water immersion (HWI) has been shown to induce various physiological adaptations that can improve athletic performance. However, the effects of post-exercise heat exposure on acute recovery and promoting training-induced performance adaptations are not well understood. The aim of this systematic review was to summarise the current evidence on the effects of post-exercise heat exposure on physical performance in healthy adults. Methods: This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A systematic search for articles was conducted in December 2023 and updated in June 2025 using the PubMed, SPOLIT, Medline, and SPORTDiscus databases. Eligible studies were randomised or crossover trials comparing whole-body post-exercise heat exposure (≥ 36 °C, e.g., hot water immersion to at least sternum level, or sauna bathing) to passive or placebo recovery. The risk of bias of the included studies was assessed using the Cochrane Collaboration Risk of Bias Tool version 2. Only studies that provided results on maximal physical performance outcomes in healthy adults were included. Results: Fourteen studies, including a total of 194 participants, met the inclusion criteria. Nine studies investigated acute effects after heat exposure and five were long-term training intervention studies. The acute studies reported uncertain results, with studies showing no effects (n = 4), beneficial (n = 4), or adverse (n = 1) effects of post-exercise heat exposure on performance recovery. The chronic studies suggested that post-exercise heating may improve running performance, at least in hot conditions. However, repeated heat exposures had no effect on cycling performance or VO<inf>2</inf>max. The overall quality of the evidence was low to moderate. The heterogeneity of study designs, heating protocols, exercise modes, performance outcomes and recovery times precluded meta-analysis. Conclusion: Based on the current evidence, it is not possible to draw definitive conclusions about the effects of post-exercise heat exposure on recovery and physical performance development. Additional high-quality studies are needed to determine the optimal heat exposure methods and recovery strategies for different types of training and performance outcomes. 

PURPOSE: The aim of this study was to investigate whether regular use of infrared sauna (IRS) after training can promote neuromuscular performance and positive changes in body composition during a 6-week training period.

METHODS: Forty female team sport athletes were pair-matched into two groups: IRS (n = 20) and control (CON; n = 20). Physical performance tests, body composition and hypertrophy measurements (dual-energy x-ray absorptiometry and ultrasound of m. vastus lateralis) were performed PRE and POST a 6-week strength and power training period, involving 2-3 sessions per week. Performance tests included a 20 m sprint, squat jump (SJ), countermovement jumps with body weight (CMJ) as well as with 15, 25, and 50% additional load (CMJ15%, CMJ25%, and CMJ50%), and a maximal isometric leg press (MVC). Participants in the IRS-group used IRS (10 min, 50℃) after training three times per week.

RESULTS: Training improved neuromuscular performance and muscle hypertrophy in both groups (p < 0.05). Following the discovery of an interaction effect for CMJ15% height (p = 0.002) and peak power (p = 0.010), post hoc tests revealed higher jump height POST-IRS (p = 0.006) and PRE-CON (p = 0.023) compared to PRE-IRS, and higher peak power POST-IRS (p = 0.002) compared to PRE-IRS. Furthermore, an interaction effect was observed for 5 m split time of the 20 m sprint (p = 0.020), but no differences were found between groups and timepoints. There were no interactions for the hypertrophy measures.

CONCLUSION: Incorporating post-exercise IRS bathing does not significantly impact hypertrophy gains, but might boost long-term power production capabilities.

Heat exposure after exercise may enhance recovery of physical performance but can also impose additional physiological stress on athletes. This study investigated the effects of post-exercise infrared sauna (IRS) on adrenal and autonomic nervous system (ANS) responses and examined how these responses adapt over time during a 6-week training intervention. Forty female team-sport athletes were pair-matched into an IRS-group and a control group (CON). Participants completed jumping exercises followed by IRS (10 min, 50 °C) or passive recovery and physiological assessments during two experimental trials: in the first (EX1) and in the last (EX2) week of the training intervention. The ANS responses were assessed by nocturnal heart rate (HR) and heart rate variability recorded before and after exercise session. Saliva cortisol concentrations, muscle soreness, and perceived recovery were assessed in the morning, before and after the exercise sessions. Cortisol increased by 5.1 ± 8.6 nmol/l the morning after EX1 in the IRS-group (p = 0.017), but not in the CON-group. Furthermore, a greater pre-post change in cortisol concentration was observed following EX1 (4.6 ± 10.4 nmol/l) compared to EX2 (−1.8 ± 7.6 nmol/l). The IRS-group showed a higher post-session HR in EX1 compared to the CON-group (61 ± 8 bpm vs. 55 ± 6 bpm; p = 0.019). Increased muscle soreness was observed at EX1 post36h only in the CON-group. Post-exercise IRS initially elevated physiological stress responses in female athletes. After six weeks of regular IRS use, athletes’ ANS balance and cortisol response adapted, suggesting effective physiological adjustment to the heat intervention within six weeks.

The International Olympic Committee's (IOC) consensus statement on 'methods for recording and reporting of epidemiological data on injury and illness in sport' recommended standardising methods to advance data collection and reporting consistency. However, additional aspects need to be considered when these methods are applied to specific sports settings. Therefore, we have developed a snow sports-specific extension of the IOC statement to promote the harmonisation of injury and illness registration methods among athletes of all levels and categories in the different disciplines governed by the International Ski and Snowboard Federation (FIS), which is also applicable to other related snow sports such as biathlon, ski mountaineering, and to some extent, para snow sports. The panel was selected with the aim of representing as many different areas of expertise/backgrounds, perspectives and diversity as possible, and all members were assigned to thematic subgroups based on their profiles. After panel formation, all members were provided with an initial draft of this extension, which was used as a basis for discussion of aspects specific to the discipline, application context, level and sex within their snow sports subgroup topic. The outcomes were then aligned with the IOC's existing consensus recommendations and incorporated into a preliminary manuscript draft. The final version of this snow sports-specific extension was developed and approved in two iterative rounds of manuscript revisions by all consensus panel members and a final meeting to clarify open discussion points. This snow sports-specific extension of the IOC statement is intended to guide researchers, international and national sports governing bodies, and other entities recording and reporting epidemiological data in snow sports to help standardise data from different sources for comparison and future research.

Aim: To retrospectively describe the annual training characteristics of elite biathletes across different age groups over 2 decades. Methods: Self-documented training-diary data from 18 elite biathletes (tier 4/5, 7 ♀, 11 ♂) between 1994 and 2014 were included in the study and classified by age group (junior: 16–18 y, U23: 19–23 y, senior: >23 y). Linear mixed models were used to analyze the effect of age group on training characteristics (intensity, distance, time, and modality shooting training) for each sex. Results: Male biathletes increased their total training volume (TV) by 34% across age groups, while female biathletes did not show increasing TV with age. Endurance TV increased from junior to senior level by 35% and 23% in both men and women. The proportional distribution of low-intensity training, moderate-intensity training,, and high-intensity training was significantly different for both sexes between age groups. Senior male biathletes shot 4% and 15% more annual shots than Under-23s and juniors due to greater number of technical and in-competition shots, while females only increased in-competition shots at senior level. Conclusion: This study provides further insights into the biathlon training puzzle, suggesting sex-specific differences in training strategies from junior to senior level. Our data may emphasize the importance of increasing endurance TV from junior to senior level by increasing the proportion of low-intensity training, with a reduction in moderate-intensity training and maintenance of high-intensity training when transitioning between age groups. Increasing the number of technical shots, as well as in-competition shots, while maintaining precision-shooting volumes may also be important for biathletes’ long-term development.