Marathon running has increased in popularity over the past three decades, with participation in the United States rising from 25,000 runners in 1976 to nearly 470,000 in 2008. Many professional and recreational runners take prescription drugs, unaware of potential side-effects that affect runners in particular.
One such class of drugs, called statins, which includes medicines such as Lipitor, Crestor and Pravachol, lowers blood cholesterol by inhibiting a cholesterol-producing enzyme and may even lower the risks of heart attack and further cardiovascular disease in a narrow category of patients.
A new study forthcoming in the American Journal of Cardiology examined the effect of statins on creatine kinase (CK), an enzyme linked to muscle damage. Elevated levels of CK in the blood and muscle after exercise correlates with muscle damage.
The study, conducted by Dr Beth Parker of the Henry Low Heart Centre at Connecticut's Hartford Hospital, is the first to measure CK levels in athletes taking statins after physical activity in a real-life environment rather than in a university laboratory.
For several years, exercise physiologists have monitored CK levels of athletes to help avoid overtraining. Marathon running and other extreme endurance events are associated with significant muscle damage. CK levels are, on average, 10 to 15 times greater or even higher 24 hours after the race.
More harm than good
Dr Parker is adamant in stressing the psychological and physiological benefits of sensible daily moderate exercise. "Raising unnecessary warnings may actually do more harm than good by deterring active folks from accruing the well-established benefits of daily activity," she said. Normally, the benefits of exercise outweigh the harm of occasional increased CK levels. But what if the CK levels are further heightened by the use of prescription drugs?
In her study, conducted with 80 well-trained marathon runners, Dr Parker found that post-race levels of CK were markedly higher in the group of runners that were using statins to treat high cholesterol when compared to a control group (runners not using statins).
There have been many reports of side-effects from statin use that include muscle pain, fatigue, a serious and acute muscle condition called rhabdomyolysis (a severe breakdown of muscle that produces substantial amounts of muscle fibre contents, which are toxic to the kidneys), impotence and scarring of the liver. Alarming problems related to emotional and cognitive abilities, including anxiety, depression and memory loss, have also been reported.
When Dr Parker was asked about the practical implications of the study, she said, "Professional and recreational athletes are reported to be intolerant of statins due to muscle complaints."
She advised clinicians to consider discontinuing drug administration for several days prior to strenuous endurance events such as a marathon.
Finally she mentioned that future research should look at CK levels after physical activity in a larger pool of subjects across more varied statin dosages. As always, further research is needed to establish how the use of statins affects subjects from different demographics.
But for now, it may be wise to consult a physician about keeping the cholesterol-lowering drugs in the cabinet several days before the big race.
An exercise physiologist, Ricardo Guerra has a Masters of Science in Sports Physiology from the Liverpool John Moores University. He has worked with several clubs and teams in the Middle East and Europe, including the Egyptian and Qatari national teams.
