Returning to running: planned heat protocol

The participant reports daily hot-tub use October 1–5, 2026, at 104°F (40°C). Duration is estimated from recollection at 15–25 minutes per session. Timing relative to runs was not recorded.

Log each session’s date, minutes immersed, water temperature, depth, placement relative to running, and response. If post-run use begins, record the change and approximate delay after exercise. A second daily session is not proposed. Future sessions will be measured rather than reconstructed.

Warning

Research exposures are not a home-use prescription. CDC guidance limits water to 40°C/104°F and advises against alcohol. Avoid adding heat while overheated or dehydrated; stop if unwell. Drink water.

Jenkins et al. (2025) studied ten trained runners over five weeks: five 45-minute immersions weekly, initially at 40°C. VO₂max rose approximately 4.4%. Most sessions immediately followed training; comparable benefits from standalone baths remain unresolved.

Zurawlew et al. (2016) found better five-kilometre performance in heat, but not temperate conditions, after six days of post-run immersion. Their 2018 morning study reduced thermal strain during morning and afternoon exercise. Neither establishes an optimal clock time or validates this participant’s recalled exposure.

Source links: Rosner’s TikTok post · @rosner_performance · Rosner’s website.