Why do people run with dumbbells in their hands? and do they have to be heavy to do so?

Question

does it exercise the biceps or triceps or both?

Answer 1

It helps build upper body strength, and no, they do not have to be heavy.

Answer 2

i think they shouldn't be too heavy. people run with them in their hands because they increase the intensity of their workout, increase the number of burned calories and provide a workout for their hands as opposed to just exercising their legs while running.

Answer 3

some pple do that and some use ankle weights they arent heavy though only 2-5lbs and it burns more cals than regular running does plus gets u to move ur arms more and helps build shoulder muscle and arm muscle without lifting the weights at a seporate time but if ur looking to bulk up there's no need to only if slimming down and "toning up" both ur bicep tricep and shoulder

Answer 4

it's a very bad idea if you have not been participating in resistance training for a long time.  all it does is increase the occurrence of shoulder injury