Cold and hot water immersion after running improve some recovery markers but not strength or mood

A randomized controlled trial assigned trained runners to either cold-water or hot-water immersion after two distinct high-intensity running protocols, then tracked a broad set of recovery indicators over 24 hours. Neither immersion type improved muscle force output or perceived fatigue, but each produced selective benefits in cardiovascular and neuromuscular measures that depended on which running protocol had preceded them.

What the study found

Neither cold-water nor hot-water immersion improved knee-extensor force—whether measured through voluntary effort or electrically evoked contractions—nor did either intervention reduce mood disturbance or perceived exertion during follow-up runs. These null results held across both running protocols and all post-exercise time points assessed.

Cold-water immersion was associated with higher cardiac vagal modulation two hours after exercise compared with a placebo condition, regardless of which running protocol participants had completed. This shift in autonomic balance suggests the heart was recovering toward a more parasympathetically dominant state more quickly, though the clinical meaning of that difference in healthy athletes remains uncertain.

Hot-water immersion was associated with lower oxygen consumption during brief submaximal runs conducted within 24 hours of the main session, a finding that held across both exercise protocols. Whether this reflects genuine improvement in running economy or a transient physiological artifact of the heat exposure is not established by this design.

Muscle activation of the vastus lateralis during maximal voluntary contractions increased at two and four hours post-exercise, but the pattern was protocol-dependent: hot-water immersion produced this effect after continuous endurance running, while cold-water immersion produced it after high-intensity interval running. This interaction suggests the type of preceding exercise stress may shape which recovery modality, if any, offers a neuromuscular benefit.

Limits worth knowing

The two running-protocol groups were analyzed separately and were small (n = 12 and n = 10), substantially limiting statistical power and the reliability of subgroup comparisons. Participants were trained runners, so findings may not extend to recreational exercisers or other populations. The study examined a single recovery session rather than repeated use over days or weeks, leaving longer-term effects unknown. Funding sources and potential conflicts of interest are not described in the available abstract. The study did not assess sleep quality, hormonal responses, or markers of muscle damage, all of which are commonly relevant to recovery research.

About this entry. The Heartwood Review summarizes published, peer-reviewed research in its own words and links to the original source. It is not medical advice; consult a physician before beginning or changing any thermal or recovery practice. Findings summarized here describe the study cited, not any product sold by Teak & Marble Atelier. Corrections.