August, 2022

Andrews, Nathaniel. J, MSc Candidate

Muscle Health Research Centre, School of Kinesiology and Health Science, Faculty of Health, York University, Toronto, Ontario, Canada

Take home message

  • Acute cold-water immersion (CWI) appears to enhance recovery of neuromuscular function or increase endurance when the next resistance or endurance exercise session is performed <1 hour after the first. For endurance exercise specifically, the benefits of CWI on recovery are linked to exercising in hot ambient conditions.
  • Using CWI 24 to 48 hours following sprint exercise may improve recovery of jump performance and strength.
  • Chronic CWI interventions after resistance, endurance, and sprint exercise show no performance benefits and can impair performance as well as blunt training adaptations.
  • Prolonged hot water immersion (HWI) potentially improves endurance in thermoneutral environments when the next exercise session is within a 2-hour period, whereas daily HWI for 5 to 6 days can aid in heat acclimation.

Background

  • CWI is a popular intervention that is believed to accelerate post-exercise recovery, improve performance, and enhance long-term training adaptations.
  • On the other hand, HWI is commonly used in rehabilitation to accelerate recovery from skeletal muscle injuries and exercise-induced muscle damage.
  • It is uncertain how effective post-exercise cooling or heating interventions are for improving acute recovery as well as in augmenting chronic training adaptations.

How the study was done

  • The literature review comprehensively investigated the effects of post-exercise cooling and heating on acute recovery of performance (e.g., strength, power, endurance) following resistance, endurance, and sprint exercise as well as the influence of CWI and HWI on chronic training adaptations.
  • CWI and HWI studies involved immersion of the whole body (up to neck depth or body and head fully submerged) or exercised limbs.
  • Temperatures for CWI ranged from 5 to 20 °C, whereas 38 to 40 °C were used for HWI.
  • Water immersion was typically performed immediately following exercise, and then functional assessments were performed at different post-recovery timepoints.

What the researchers found

  • Resistance exercise:
    • Acute CWI – Application between 5 to 40 minutes post-exercise could increase recovery of strength, but no effect or negative effects were observed for endurance at 24 to 72 hours post-exercise.
    • Chronic CWI – At 4 to 8 weeks, no changes were observed with repeated CWI use on training adaptations, but CWI over 12 weeks of resistance training blunted strength gains and impaired endurance.
    • Acute or Chronic HWI – No benefits were observed on performance or adaptations
  • Endurance exercise:
    • Acute CWI – Application for <30 minutes improved endurance in hot temperatures when subsequent exercise was performed <1hour after the initial session. However, cooling >2 hours impaired recovery of endurance and no influence or negative impacts on jump performance and strength. In addition, using CWI between 24 to 72 hours post-exercise did not promote recovery of endurance or neuromuscular function
    • Chronic CWI – No improvements were observed for post-exercise endurance for up to 5 weeks.
    • Acute or Chronic HWI – Prolonged 2-hour HWI increased endurance during subsequent exercise performed 2 hours after the initial session, and daily HWI post-exercise over 5-6 days may improve acclimation to hot environments. However, 4 weeks of HWI did not improve running performance.
  • Sprint exercise:
    • Acute CWI – Potential benefits in jump performance and strength recovery were observed at 24 to 48 hours post-exercise. In contrast, CWI blunted sprint performance when applied 15 to 60 minutes post-exercise, but CWI of up to 2 hours did not alter strength or jump performance recovery post-exercise.
    • Chronic CWI – Repeated use of CWI did not alter sprint exercise training adaptations.

Conclusion

  • This article provides a summary of the evidence-based research that exists and how to best implement CWI or HWI to enhance the post-exercise recovery of exercise performance.
  • Nonetheless, the efficacy of post-exercise heating and cooling on functional performance depends on various factors such as exercise-type, timing of application, water temperature, whether recovery methods were acute or chronic, and temperature of the exercise environment.
  • Potential limitations in studies utilizing CWI or HWI include a lack of standardized heating or cooling protocols, and difficulty with designing a placebo.

References

Chaillou, T., Treigyte, V., Mosely, S., Brazaitis, M., Venckunas, T., & Cheng, A. J. (2022). Functional impact of post-exercise cooling and heating on recovery and training adaptations: Application to resistance, endurance, and sprint exercise. Sports Medicine-Open, 8(1), 1-26.