Dr. Hansaji Yogendra is making a subtler point than most people will catch. The headline promises the benefits of hot baths, but the real message is about temperature specificity. Hot water for circulation and muscle recovery. Warm water for joint pain and swelling. Normal temperature water for immune function. She's not saying hot baths are universally good — she's mapping different water temperatures to different physiological outcomes. That distinction matters more than most people realize.
It's the kind of nuance that gets lost when wellness content gets compressed into "hot baths are good for you." They can be. But the dose, the temperature, and your baseline health status all shape whether you're building resilience or creating a new problem.
The 2018 paper on habitual hot water bathing and cardiovascular function is worth paying attention to here. That research found regular hot water immersion produced vascular adaptations similar to aerobic exercise — improved arterial compliance, lower resting blood pressure over time, better endothelial function. The mechanism is the same one Yogendra is describing: vasodilation, increased blood flow, a cardiovascular training effect. The Finnish sauna literature tells the same story, just with higher temperatures and longer durations. Hot water bathing appears to be a gentler entry point into the same physiological territory.
The 2021 hydrotherapy review puts this in a longer historical context. Hydrotherapy isn't a wellness trend — it's one of the oldest therapeutic modalities in human history, with documented use across Roman, Japanese, Finnish, and Ayurvedic traditions. The mechanisms we're now measuring with lab instruments are the same ones those traditions intuited through centuries of practice.
Here's where I want to add some nuance to Yogendra's framing. She recommends normal temperature water for immune support and increased white blood cell count — and that's accurate. But the cold exposure literature goes further in this direction. Controlled cold stress, not just neutral temperature water, produces more pronounced immune activation: higher natural killer cell activity, elevated norepinephrine, the kind of robust immune priming that the Wim Hof protocols have demonstrated. Normal temperature bathing is a gentle nudge. Cold exposure is a more deliberate signal.
The caution around high blood pressure is worth taking seriously. Vasodilation from hot water can cause a sudden drop in blood pressure as you step out — that's the dizziness some people experience. And for those with poorly controlled hypertension, the initial blood pressure spike before vasodilation kicks in is the real concern. Warm water, not hot, is the safer protocol for that population.
Use temperature as a tool, not a default. Hot water — 104 to 109 degrees Fahrenheit — for post-workout muscle recovery and circulation. Warm water for joint pain, puffiness, or when you want the relaxation without the cardiovascular demand. Cold water when you want immune activation and the alertness cascade. And contrast — alternating between hot and cold — when you want all of it: the cardiovascular adaptation, the immune priming, the neurochemical clarity that comes from pushing your body through temperature extremes and letting it find equilibrium again.
The surprising insight here is that your bathtub is already a contrast therapy device waiting to be used deliberately. Most people pick a temperature out of habit or comfort. The research suggests you should pick a temperature based on what you're trying to accomplish. That's the shift from bathing as routine to bathing as ritual.