better for cardio, walk or elliptical?

I have no idea but I do both because mentally I get bored doing the same thing over and over again. But usually I do HIIT on the elliptical and walk for an active rest day. I do know elliptical HIIT has helped my running speed far more than walking does.

Good choice to walk rather then sit. As for the better of the two....If your goal is to burn more calories per minute of exercise, then the elliptical will usually win over walking. However, elliptical,walking, running, whatever are all about the same as from a cardio standpoint at its most basic form. Which translated means it is more important to concentrate on time vs efficency of the exercise. The body will only start burning it's fat reserves after about 45-60 minutes of aerobic exercise, so 90 minutes of walking is better then 50 minutes of elliptical (same calories burned approx), the time spent exercising will determine which calories in your body will be used. Keep it up, good luck!

As far as cardio health goes, they're fairly equal. Of course it depends on what exactly you're doing - how fast you're walking, terrain, resistance on elliptical, swinging arms or not in either activity, etc. In your case, I would actually say the elliptical is the winner as you heart rate gets higher.

However, if we're talking overall physical fitness, walking is definitely the winner. The movement engages stabiliziers (improve balance/coordination) and the impact of foot falls promotes bone stengthening. While the elliptical might engage the stabiliziers depending on how you're using it, there is little to no impact as your feet remain planted the whole time.

P.S. I would highly recommend increasing the resistance on your elliptical. It's a common misconception that going faster is better. While working harder is actually your best bet. Increasing the resistance will also get your heart rate up because you're working harder. Think of it like the difference between walking a flat surface and walking uphill. Your heart rate will increase while walking flat because you're moving but it will REALLY increase when you go uphill because you're essentially fighting gravity to lift yourself up that hill which takes much more muscular effort. Same with increased resistance, your muscle are working harder to push through that same motion.

P.P.S. If your elliptical doesn't have moving arms, I would also high recommend trying to swing your arms anyway. This really engages your stabilizers, especially your core and will also help elevate your heart rate. Just be careful - wouldn't want anyone hurting themselves!

Interesting article, thanks for posting the link.

My first thought was whichever one you're going to do the most of.

After that, and with no scientific back up... walking outside over walking on a treadmill or using and elliptical, but not so much difference between treadmill and elliptical. Also take into consideration the resistence/incline used as well as whether the elliptical has arms to engage your arms as well.

It depends on how much work you are doing. Walking is good for general life/health/psychological benefits, but not great for calorie burning unless you really speed up or add hills.

I find it very easy to get my heart rate up on the elliptical. I increase the incline and go fast. I use it for HIIT. I use walking for activity.

But don't forget your strength training, that is important as well.