I do not walk any certain number of minutes, I just walk a fast mile everyday. Am I getting sufficient exercise? (I can really feel my leg muscles burn!)
Walking as fast as you can is definitely the right idea. I guess the opposite of that is someone who walks exactly 30 minutes each day, but has a slow to moderate pace. The problem is that a quick mile may only take you about 15-20 minutes (or less if you have been doing it for a while). Experts agree that if you did this 3 times per day, it would be similar to a 30 minute workout, but it doesn’t sound like you’re doing that.
I think you need to vary your workouts to get the most effective results. Your body has two major energy systems: one for short, hard bursts of effort and another for moderate, sustained exercise. So you should include both types of walking into each week. You can build this around your schedule so that on your hectic days you focus on intensity and speed and maybe progress to walking more than just one mile. On the other days when you have more time, go for distance and walk at a pace that you can keep up for at least 30-45 minutes.
Another idea is to mix it up and do a combination of both in one walk: say, walk one mile at a vigorous pace and then walk 2 miles at a slower (but still challenging) pace.
It is a good idea to walk daily but not more than 5 days per week. If you notice that suddenly your heart rate shoots up, you could be over-training or dehydrated. Make sure you drink lots of water, especially in the warmer months coming up. Never walk to exhaustion, and if you feel any type of nagging pain that could turn into an injury, stop and have it checked out.