When you are doing your BRISK walk or bike ride PLEASE enjoy the NATURAL sounds and sights instead of listening with your Ipod/Nano or talking on your cell phone. I’m sure that Apple and other makers of these devices are not going to be happy with this recommendation.
You want to immerse yourself in the NATURAL surroundings and it could also save your life! I constantly see people riding on their bikes with the ears covered with earbuds. If they have the sound turned up to levels where you can hear them when they pass by, then how can they be aware of emergency sirens!
Further more I will tell you as a short lived but former radio DJ my colleagues would blast the music through their headphones for their entire shift! They were setting themselves up for now wearing hearing aids like my members of the American Legion who were in Vietnam. LOUD music DESTROYS the sensitive interior ear hairs that you must have!
I hate to say it but the profession of being an audiologist in the hearing aid industry is going to BOOM for the next 50 years or more! I was shocked to find that some of the new high tech hearing aids go for upwards of $7500 or more!