(Note: this is not the study article nor an abstract of the article, but a news report about the study. Still useful information for us old guys.)
From Medscape Medical News
High-Impact Exercise Reduces Stroke Risk
November 24, 2009 — Regular workouts are protective against ischemic stroke, say researchers. They suggest that the intensity of the activity is important and the effect is independent of the improvement exercise has on hypertension, diabetes, or dyslipidemia.
"We believe that maintaining, and even initiating, moderate- to heavy-intensity activity, such as racket sports or swimming, is an important component of risk reduction strategies against ischemic stroke," said Joshua Willey, MD, from Columbia University in New York.
"We are alarmed by the high percentage that was physically inactive."
Dr. Joshua Willey
"We are alarmed by the high percentage — 40.5% — of our sample that was physically inactive," he told Medscape Neurology.
The research team looked at more than 3000 people from the Northern Manhattan Study. Only 20% reported that they regularly participated in moderate- to heavy-intensity activities.
The average age of the study sample was 69 years, and participants were followed up for approximately 9 years. During that time, there were 238 strokes.
The results appear in the November 24 issue of Neurology and point to the benefits of high-impact workouts.
"We were somewhat surprised that the total energy expended was not associated with risk of ischemic stroke, but the intensity itself was," Dr. Willey said. "This could represent difficulties with measuring total energy expended in the elderly, or it may be that the ability to perform more moderate- to heavy-intensity activity is indicative of overall good health."
Table. Risk of Ischemic Stroke Associated With Physical Activity
Intensity of Activity Adjusted Hazard Ratio (95% Confidence Interval)
Any vs none 0.86 (0.66 – 1.13)
Light vs none 0.94 (0.71 – 1.25)
Moderate to heavy vs none 0.65 (0.43 – 0.98)
Moderate to heavy vs light to none 0.68 (0.46 – 0.99)
These results are contrary to other studies that found that even light exercise reduced the risk of stroke. In the Nurses' Health Study and the Women's Health Initiative Observational Study, even mild-intensity activity, such as walking, was beneficial.
"Due to the number of events, we may not have been able to detect more subtle protective effects from light-intensity activity that others have found," Dr. Willey explained.
Surprisingly, the protective effect investigators observed occurred only in men and not in women. "This may not be an actual biological phenomenon," he said. "There may be factors that we had not measured in our study, such as hormone replacement therapy." Some have suggested that hormone replacement increases the risk for stroke and influences physical activity.
Dr. Willey also points out that the cohort included older people with a high prevalence of physical inactivity and other stroke risk factors. He emphasized that there are many benefits of regular workouts beyond reduction of ischemic stroke. "Our findings should not discourage women from exercising," he said.
This study was funded by the National Institutes of Health. Dr. Willey has disclosed no relevant financial relationships.