Exercise is the key to good health, but as with anything—even water or vitamins—too much of a good thing can be dangerous. For 41-year-old Gemma Underwood, a Scottish fitness enthusiast and orange belt in karate, her passion for training nearly cost her life. What started as an “intense” martial arts session led her down a frightening path to the emergency room, where she was diagnosed with a rare and potentially deadly condition called rhabdomyolysis. Her story is a sobering reminder for gym-goers and athletes everywhere: fitness without balance can be fatal.It was just another training day in March for Underwood in South Ayrshire, Scotland. Her karate session had been grueling, pushing her physical boundaries, but she felt satisfied—until the next morning. Unable to get out of bed due to severe muscle pain and swelling, she noticed her arms had ballooned, and her muscles were extremely tight. But the most alarming sign was what she saw in the bathroom mirror: her urine had turned a disturbing dark brown, which she described as resembling “Coca-Cola.”Panicked and confused, Underwood rushed to the emergency room. Medical professionals quickly diagnosed her with rhabdomyolysis, often referred to as “rhabdo,” a serious condition involving the breakdown of muscle tissue that releases toxic proteins—specifically myoglobin—into the bloodstream. If untreated, these proteins can clog the kidneys, leading to kidney failure or even death.What is Rhabdomyolysis?Rhabdomyolysis is not commonly discussed in mainstream fitness conversations, but it’s a well-known risk among medical professionals and elite trainers. According to the Cleveland Clinic, rhabdo occurs when skeletal muscle breaks down rapidly due to extreme physical exertion, trauma, or dehydration. As muscle fibers die, they release their contents into the bloodstream, overwhelming the kidneys and potentially causing multi-organ failure.Symptoms vary and can be deceptively mild in early stages. They typically include:Muscle pain, swelling, or tendernessWeakness or difficulty moving limbsFatigue or malaiseNausea or vomitingSignificantly reduced urination or dark-colored urine (a major red flag)In Underwood’s case, the condition escalated quickly—an all-too-common reality when the signs are misunderstood or ignored. Doctors told her the cause was likely inadequate hydration during her intense workout. “I wasn’t hydrated enough,” she admitted. “I should have been drinking more water before.”Water plays a vital role in preventing rhabdomyolysis. Without enough fluids, the kidneys struggle to flush out myoglobin and other harmful muscle breakdown products. During strenuous exercise, particularly in high-heat environments or lengthy sessions, fluid loss through sweat increases dramatically. If not replenished, the body enters a state of dehydration, magnifying the impact of muscle strain.Despite being fit and experienced, Underwood made the critical mistake of underestimating her hydration needs—a mistake that nearly proved fatal.Underwood spent five days in the hospital receiving intravenous fluids and was fitted with a catheter to monitor kidney function. She’s now on a mandatory exercise hiatus for at least three weeks and has made hydration a top priority.“I’m currently resting, no exercise at all, and drinking plenty of fluids,” she shared. “It was terrifying knowing I could’ve died from something that seemed so routine. Make sure you're hydrated before any workout, no matter how intense it is.”Her message is clear: no one is immune to the dangers of overtraining. Her story is a cautionary tale not just for elite athletes but for anyone who steps into a gym or takes on a new fitness challenge without adequate preparation.How to Exercise Smart and Stay Safe?While rhabdomyolysis is rare, it’s becoming increasingly common among high-intensity workout communities, especially in CrossFit, spin classes, and boot camps where participants are encouraged to push limits. The good news? It’s entirely preventable.Here’s what every exerciser should remember:Hydration is non-negotiable: Drink water before, during, and after workouts. Electrolytes help too.Ease into new routines. Whether you’re new to fitness or returning after a break, increase intensity gradually.Listen to your body. Pain and fatigue are signals, not challenges to override.Know the symptoms. Dark urine, severe swelling, and unexplained weakness are not to be ignored.Rest and recovery matter. Muscles grow and repair when you rest—not when you overtrain.