A biomedical engineer claims that spending 100 days living underwater has reversed his biological aging by more than a decade. Joseph Dituri conducted a self-experiment by residing for 100 consecutive days in an underwater habitat 22 feet (about 6.7 meters) below the surface off Key Largo, Florida. The mission exposed his body to elevated pressure and higher oxygen levels, similar to hyperbaric oxygen therapy. After resurfacing, Dituri reported dramatic health improvements: a 72-point reduction in cholesterol, significantly lower inflammation markers, increased testosterone levels, nearly doubled restorative REM sleep, and enhanced brain connectivity according to neural scans. The most striking claim is that the hyperbaric environment appeared to influence his telomeres, the protective caps on chromosomes that shorten with age, effectively slowing or reversing aspects of biological aging. While brain imaging showed improved cognitive connectivity, the scientific community is cautious. As a single-subject case study, the results cannot be considered definitive proof of age reversal. Many experts note that claims about hyperbaric oxygen therapy and longevity have historically faced skepticism due to limited large-scale evidence. Nevertheless, Dituri’s project has generated significant interest in environmental and hyperbaric medicine. Larger clinical trials are now underway to investigate whether controlled exposure to high-pressure, high-oxygen conditions can deliver measurable, long-term benefits for human health and aging.