Low cardio fitness levels foreshadow stroke risk

WASHINGTON - Lower levels of cardio-respiratory fitness in men can increase the risk of death due to stroke by sixty percent, a new study has found.

The study was conducted at the University of South Carolina’s (USC) Arnold School of Public Health (ASPH).

A stroke is a condition where a blood clot or ruptured artery or blood vessel interrupts blood flow to an area of the brain. Cardio-respiratory fitness was shown to be a reliable predictor of stroke risk.

Researchers analysed data on 45,706 men aged 18 to 100 years, grouped as having low, moderate or high levels of cardio-respiratory fitness as measured by a maximal treadmill exercise test.

A lack of oxygen and glucose (sugar) flowing to the brain leads to the death of brain cells and brain damage, often resulting in an impairment in speech, movement and memory.

Based on self-reported information, participants were deemed as sedentary, walker-jogger-runners, or sports participants.

The study was controlled for age, cholesterol levels, diabetes, smoking, alcohol use and family history of cardiovascular disease.

The rate of fatal stroke among low-fit men was 3.2 per 10,000 man-years, compared to 2.0 for both moderately and highly fit men.

Non-fatal stroke rates were 10.8, 8.9 and 6.4 for low, moderate and high fitness levels, respectively. Incidence of total stroke showed a strong inverse relationship with increasing levels of fitness.

While men who ran, jogged, walked or played sports tended to have higher fitness levels, activity levels alone were not an independent predictor of stroke risk.

“These findings suggest that health professionals might consider assessing their patients’ cardio-respiratory fitness and counselling them to improve fitness levels to prevent stroke,” said John Sieverdes, a doctoral scholar at ASPH who led the study.

“While physical activity has been shown to reduce health risks, this study concluded that fitness level was closely associated with stroke prevention,” said Sieverdes.

Participants were enrolled in the Aerobics Centre Longitudinal Study in Dallas, Texas between 1970 and 2001 and had no history of stroke, myocardial infarction or cancer at their baseline visit, said a release of ASPH.

The findings were presented Thursday at the American College of Sports Medicine’s 57th Annual Meeting in Baltimore.