Systematic review finds little evidence that contrast therapy improves heart or metabolic health

Researchers conducted a PRISMA-guided systematic review of interventional studies examining how alternating heat and cold exposure affects cardiovascular and metabolic markers, ultimately synthesizing data from 19 of 21 eligible studies. The review found minimal support for effects on resting heart rate, blood pressure, vascular function, or markers of glucose and lipid metabolism.

What the study found

The review identified little to no evidence that contrast therapy meaningfully shifts resting heart rate, blood pressure, or vascular health indicators — all established markers of cardiovascular risk. Similarly, metabolic outcomes including glucose regulation and lipid profiles showed little response to the intervention across the included studies.

The one area where a signal did emerge was physiological adaptation to thermal stress itself: repeated alternating heat and cold exposure appeared to blunt the acute rises in heart rate and core body temperature that typically accompany heat exposure, and was associated with modestly lower resting core temperature over time. The authors characterize this as evidence of heat adaptation rather than a broader cardiometabolic benefit.

The authors are explicit that the evidence base is insufficient to support firm conclusions or practical recommendations. They call for larger, well-controlled studies with systematic measurement of vascular and metabolic endpoints to clarify both the short-term and long-term effects of contrast therapy on cardiometabolic health.

Limits worth knowing

The review synthesized only 19 studies, a relatively small pool that likely reflects the early state of the research field rather than a comprehensive evidence base. Heterogeneity in protocols, populations, outcome measures, and follow-up durations across included studies complicates direct comparison, even with standardized mean difference conversions. The review searched literature only through mid-2025 and was limited to three databases. Funding sources for the review itself are not disclosed in the abstract, and the individual included studies may vary in methodological quality. Long-term cardiometabolic outcomes and effects in specific subpopulations were not separately analyzed.

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.