Upping Exercise Question

Hi everyone.  I could use some advice for my workouts.  I'm in the gym 5 days a week.  I do the treadmill for 1/2 an hour, and then do weights.  I'm currently walking at 3.5 miles an hour, and I feel I'm ready to do more.  My question is this:  would it be better for my weight loss to concentrate on doing longer times (maybe extending to 35 minutes, and adding 5 minutes a week) or upping the speed?  Or should I alternate, adding minutes this week, then a little faster next week, etc?

For calorie burn, you are probably better off upping the intensity over increasing the time.

You can go faster, or you can stay at 3.5 and increase the incline.

I have a real problem with boredom, so I do 5 mins at 3.5 walk, then, I start to increase my incline 1 click every minute for 12 minutes, then decrease 1 click every minute for 12 minutes then finish off at 3.5.

My arthritic ankle can take that better than trying to go faster.

The best exercise is the exercise you like - what do you want to do?  Exercise isn't much of a factor in weight loss.  It's great for your health and overall fitness, but you can't outrun a bad diet as they say.  

The best way to change it would be high intensity interval teaining. Lots of info out yhere on HIIT

^^ What Grim said!   If time isn't a problem it's always better for over-fat people to work out longer, not harder.  However, for most of us time is a precious commodity.  To get in more of a calorie burn and to increase your stamina, high-intensity interval training is the bomb.  

You can do this with a treadmill or any other piece of gym equipment by changing up the speeds/incline/resistance.  Good luck!  

Great advice everyone and sometimes its good to change it up.  Do something different for your cardio intensity  Keep us posted on how you are doing.

Happy Holidays!