The most interesting observations involved the response of salivary T to the different recovery conditions. Post high-intensity exercise conditions of PR, 15- and 25-minute CWI led to decreased T at 24 hours post-exercise, when compared to immediately after high-intensity exercise, while 35 minutes of CWI did not cause statistically-significantly changes in T from immediately post-exercise to the 24-hour mark. T at 24 hours post high-intensity exercise was also higher than 1 hour post high-intensity exercise for the 25- and 35-minutes CWI conditions. Additionally, T demonstrated a rebound effect with the 35-minute CWI condition, resulting in increased T 48 hours post high-intensity exercise when compared to baseline (Table 1). These results suggest that longer bouts of CWI after high-intensity exercise may lead to increased T 48 hours post high-intensity exercise. This data suggests that a 35-minute bout of CWI following exercise may be an effective method for trying to increase T 24 and 48 hours post high-intensity exercise when compared to PR.
These results support the previous claims that the hormonal response to high intensity exercise will lead to an increase in both T and C.4,1314 The results also suggest that, regardless of the method of recovery following exercise, either PR or differing times of CWI, C will remain elevated 1 hour post workout and become no longer significantly different from baseline levels 24 and 48 hours post high-intensity exercise.
While results suggest that longer bouts of CWI may increase prolonged recovery in athletes regarding T, it is also important to mention that TCR had no statistically significant changes between conditions. The TCR can be a useful tool in measuring athlete recovery following high-intensity exercise.8 If one would base the status of athlete recovery solely off TCR, it may suggest that CWI has no significant effect on the hormonal response of T and C regarding athlete recovery post high-intensity exercise, which is consistent with other findings.14 Therefore, it is also important to focus on the hormonal responses to high-intensity exercise by looking at each hormonal response independently. While there may have been no significant difference across conditions for TCR or C, conditions of CWI that consisted of 25 and 35 minutes showed to have significant effects on T after high-intensity exercise, which is contrary to other findings.14 These results suggest that PR may have better acute physiological effects as compared to CWI regarding immediate-post high-intensity exercise T, which is a consistent finding.15,16
Practical applications of these results suggest an athlete may want to determine their recovery method following high-intensity exercise depending on their recovery goal. When seeking the goal of acute recovery, results suggest an athlete may want to partake in PR as compared to longer bouts of CWI; however, the data suggests CWI may be more beneficial for prolonged recovery. Examples of clinical situations may be observed during two-a-days when athletes want to recovery quickly before another practice later that day. PR showed results of elevated T 1 hour post high-intensity exercise, as compared to decreased T 1 hour post high-intensity exercise for all CWI conditions. If an athlete has the goal of recovery within a limited time, it may be more beneficial for that athlete to maintain higher T between bouts of exercise, decreasing their catabolic state. When athletes have a longer time to recover, such as a day or two before competition or single practice days, longer bouts of CWI may be more beneficial for athletes. With data showing elevated T 48 hours post exercise when compared to baseline T, recommendations of 35-minute CWI post-exercise may be warranted for athletes whose recovery goals are to reach a peak in T 48 hours after high intensity exercise. Some limitations of this study include the small number of participants as well as the inability to control outside factors, such as diet or normal activity levels of participants with certainty between testing windows. Another limitation would be that longer bouts of CWI such as 35 minutes are generally not common amongst athletes; it might be difficult for an athlete to partake in CWI for longer bouts during busy times where there is a high demand for cold whirlpools.
Clinical applications of these results should be taken into consideration when evaluating the recovery goals of athletes. Recommendations of PR after post high-intensity exercise may be more beneficial when athletes aim for acute physiological changes that lead to recovery. Conversely, longer bouts of CWI, for example 35 minutes, may be more beneficial to athletes who have increased amounts of time to recover. Further studies are needed to investigate the hormonal response to high intensity exercise within the 1 hour and 24 hour post high intensity exercise window to be able to make more evidence-based recommendations with regards to athlete recovery.