Certain activities demand focus if you desire good outcome. Prayer/Sadhna is one known activity.
Exercise/Running/Cycling is one such activity. You need to be with self for the designated time frame. No family, no phone, no chit-chat, no music.
When you go for run equipped with IPod, you divide your attention among senses. Your mind wither frequently. Billions cells will not participate in activity and will never get gratified properly.
Division of attention = inefficient execution of tasks among whom attention is divided.
You and your body. Period.
Try it. Your exercise throughput will increase manifold. Billions cells of your body-Nation will be indebted. Senses will be gratified.