Short read
Douzi and colleagues at Poitiers, Landquart, Fribourg and Montreal published a narrative review in the International Journal of Biometeorology in 2026. It sets out what heat exposure and cold exposure each do, and asks what happens when the two are combined.
The single most useful sentence in it is not a result. It is a statement about the state of the field: it remains uncertain whether combining these two stimuli offers greater, lesser, or simply different benefits compared with each modality alone. The authors add that relatively few studies compare these protocols directly, and that further research is needed to clarify whether the opposing physiological responses of each therapy may interfere with each other, thereby compromising their effectiveness.
This is a narrative review. There is no systematic search, no risk-of-bias assessment, no pooled effect and no dose. It does not show that contrast fails, and it does not show that contrast works. It shows that the question has not been answered.
That is worth citing precisely because it comes from the people who study this for a living. Any caveat heatdive writes about contrast is weaker than the one the field writes about itself.