Passive income: NO

Earning passive income solely from the side hustle of Cold Therapy and Thermal Contrast Optimization is unlikely for most individuals. While some automation and outsourcing can be implemented to streamline processes, achieving true passivity typically requires ongoing effort and involvement. Most people do not reach a level where this hustle becomes entirely passive, with only a few outliers experiencing significant passive income. My research across various platforms like Reddit, Twitter, and YouTube indicates that while some individuals share success stories, they are often the exception rather than the norm. It's important to note that myths and misleading expectations about the ease of achieving passive income in this niche can lead to disappointment. Overall, the potential for passive income from this side hustle alone is limited, and diversifying income streams may be necessary for sustained profitability.