By Dr. Brian McDonough, Medical Editor

PHILADELPHIA (CBS) - We talked about it last week and it is worth clarifying. The question is,‘what is better – running or walking?’

Most of us have been raised with the concept that more is better so most of us think it is running. Well, when it comes to protection against heart disease, several recent studies have found that walking for extended periods of time and with regularity can help and in some ways be more effective than running.

Twenty to thirty minutes, three times a week can help prevent the long-term damage. Running can have a similar effect, but for many, it’s difficult to sustain a regular running program.

This is the key issue – you want something that is moderate and sustainable.

Certainly if we all had the time each day to work out with light weights, run and then play a round of golf it would be better than walking twenty to thirty minutes but the reality is we need something that can be sustained. That is what works.