A game of tennis offers moderate to strenuous exercise, so do exercises like biking, swimming and jogging.
The study, which was published in the Journal of Neurology, found this kind of exercise might be keeping the brains of older people from developing an internal injury.
Dr. Joshua Willey studied the MRI scans of over 1,200 people. Their average age was 70.
Those who said their exercise was more intense and frequent showed fewer silent strokes when they were scanned, suggesting that the intensity of the exercise offers some protection to the brain.
Silent strokes have no symptoms but "can" signal some future danger. A silent stroke seems to be linked with things like memory problems, or mobility in the elderly or of a future risk of a stroke with clinical symptoms.
Although a lighter exercise like walking and yoga did not show an association with brain protection, Dr. Willeys says that even a lighter exercise offers health advantages.
Now if you didn't exercise today, it's okay. You get an excuse, because exercising in hot weather requires some thought and some precautions. Exercising in heated temperature puts extra stress on the heart.
So during the hotter months, exercise outside only during the cooler morning and evening hours. Also, remember to hydrate well. Half an hour before exercising, drink a full glass of water, then one every 30 minutes. Also, wear hats and loose fitting clothes that will let your body breathe. And be sure limit your exercise outdoors to no more than one hour.
Follow these rules and stay safe.