Wow..... What a bad thing to say that one guy...
Four hours is ridiculously unnecessary. Get a pair of roller blades and go balls out for a half an hour. Garuntee you'll get a better workout then any four hour walk. Really, walking isn't excerise. Jog, run, roller blade, ride a bike. Walking is pretty worthless, unless you never excerise, I guess its a good place to start..
To tell anyone that a proven successful exercise such as walking is worthless is similar to telling an obese person they should only eat 3 celery sticks a day. Whereas as it is true you burn more calories running in the same time you walk, a lot of us here are not yet fit enough, and running simply isnt an option. But calling it worthless devalues it entirely. I am speaking from very personal experience here. When I was at my heaviest 3 months ago, had I considered walking to be worthless and jumped right into running I would have hurt myself and become so dissapointed and discouraged, I would have stopped all together, like many many times before. Instead I was smart and started walking. At first I could only walk for 15-20 minutes a day before my body was wracked with pains I was unaccustomed to. Then slowly they became easier, so I went 30 minutes. Then as that got easier I started power walking, and so on, to the point now I am power walking 10km a day. And in those 3 months of slowly working myself up to running (which I just started) I lost more than 30 pounds!! Hardly worthless!
If you google walking vs. running you will find literally TONS of information out there. Now you are right in that running does burn more calories faster, but the person has to be strong enough to do so without injuring themselves. Walking is an exercise almost any person in the world can do, at any age and any fitness level. It is probably the most important activity any person just starting a fitness level can do to prepare themselves.
Would you reccomend a person who has not weight trained before that if they are not bench pressing 200 pounds it isnt worth it? Everyone needs to start somewhere. Walking is simply a fantastic exercise no matter how you look at. Everyone learns to walk before they can run, the same holds true in any exercise. Power to you if you can run and burn more calories faster than me, but I am still burning calories too, nothing worthless about it.
Sorry if I seem like I am preaching, but this is a sensitive subject to me. When people come on here offering what I consider to be poor advice I see the possible damage it could cause, and it bothers me a lot. If someone actually believed you and thought to themselves "Walking is worthless" but was not yet able to run, they could very well injure themselves and set themselves so far back that they might never try again.
I hope you can see how this kind of advice could be more damaging than helpful. If a person simply cannot yet do something, telling them to adopt a "all or nothing" attitude is harmful and dangerous on many different levels. Some of the folks here really do have no idea how to begin this journey and we need to encourage them in every way possible. Telling them their efforts are worthless is the worst thing you could possibly do.
sirant