Extreme exercise can cause harmful side effect
Three years ago, Christina D’Ambrosio went to her first spin class, pedaling fast on a stationary bike to the rhythms of popular music as an instructor shouted motivation.
But D’Ambrosio, who exercises regularly, found the hour- long class was harder than she anticipated. By the end her legs were sore and wobbly.
‘‘ I thought my body just wasn’t used to that kind of muscle ache because it was my first class,’’ said D’Ambrosio, a kindergarten teacher from Pleasantville, New York.
Over the next two days, her legs throbbed with excruciating pain, her urine turned a dark shade of brown, and she felt nauseated. Eventually she went to a hospital, where she was told she had rhabdomyolysis, a rare but lifethreatening condition often caused by extreme exercise. It occurs when overworked muscles begin to die and leak their contents into the bloodstream, straining the kidneys and causing severe pain.
After a two- week hospital stay, D’Ambrosio was released and has since recovered. Her case was highlighted in April in The American Journal of Medicine along with two other cases of spinning- induced rhabdomyolysis treated by the same doctors.
The report noted that at least 46 other cases of people developing the condition after a spin class were documented in the medical literature, 42 of them in people taking their first class. The report cautioned that the condition was very rare, and not a reason to avoid high- intensity exercise. But the authors said their goal was to raise public awareness so that people who begin a tough new workout program will ease into it to lower their risk of injury.
‘‘ I would never discourage exercise ever,’’ said Alan Coffino, the chairman of medicine at Northern Westchester Hospital in Mount Kisco, N.Y., and a co-author of the new study. ‘‘Spin class is a great exercise. But it’s not an activity where you start off at full speed. And it’s important for the public to realize this and for trainers to realize this.’’
Rhabdo, as many experts call the condition, has long been documented among soldiers, firefighters and others whose professions can be physically demanding. An Army study in 2012 estimated that about 400 cases of the condition are diagnosed among active- duty soldiers each year. On occasion there have also been large clusters of college athletes hospitalized with it after particularly grueling workouts.
But doctors say they are now seeing more of it among weekend warriors, driven in part by the popularity of high- intensity workouts. Spinning, in particular, has gained a huge following; large chains like FlyWheel, SoulCycle and others report millions of rides and tens of millions in annual sales. Studies show that high- intensity exercise offers myriad health benefits, but for a small subset of people, many of them beginners, rhabdo can crop up and quickly turn ugly.
In 2014, doctors at NewYorkPresbyterian Weill Cornell Medical Center in New York City published a report on two patients who arrived at the emergency room with rhabdo shortly after their first spin class. One was a 24- year- old woman hobbled by pain, her legs swollen and feeling ‘‘ as tight as drums.’’ She was rushed to surgery, where doctors sliced her thighs open to relieve a dangerous buildup of pressure.
Another study found that between 2010 and 2014, there were 29 emergency room visits for exercise- induced rhabdo at NewYork-Presbyterian alone. Weightlifting, CrossFit, running and P90X were the reasons for some visits. But the most common one was spinning.
There is some evidence that certain medications, including statins, stimulants and antipsychotic drugs, as well as genetic susceptibilities may contribute to the condition, said Patricia Deuster, a professor of military and emergency medicine at the Uniformed Services University of the Health Sciences in Bethesda, Maryland.
But in general it occurs when people simply do not give their muscles time to adjust to an aggressive new exercise, experts say. A little damage to muscles is a good thing because that stimulates them to grow and adapt to stress. But when the stress is too great, fibers are destroyed. When that happens, they break apart and release compounds that can be harmful to the liver, such as a protein called myoglobin, which causes brown or tea- colored urine, a classic symptom of rhabdo.
While almost any intense activity can cause rhabdo, it almost always strikes people who are doing something new. That is why people should always progress from light to moderate and then vigorous intensity when doing a new exercise, said Eric Rawson, chair of the department of health, nutrition and exercise science at Messiah College in Mechanicsburg, Pennsylvania.
‘‘ You can be fit, and I can come up with a workout that you are unaccustomed to, and that could be what causes rhabdo,’’ he said.
Two things can help you avoid rhabdo, said Joe Cannon, an exercise physiologist and personal trainer in suburban Philadelphia. Before starting a new program, do a less intense version of it first. That means riding a stationary bike at a moderate pace before starting a spin class, or doing just one set of a weight lifting exercise rather than multiple sets and repetitions.
But the most important advice is to know your limits: Don’t be afraid to leave a class or to say no to a trainer if you are struggling.