I live in the Sierra foothills and walk 3+ miles several times a week. The walk includes some very steep climbs. Sometimes I carry two 5 pound weights to do arm exercises (shoulder presses and bicep curls.) I usually do 20 reps per side, doing about 10 sets per walk.
Am I burning any extra calories for using the weights or is the benefit just the toning in my arms?
You are definitely burning extra calories by carrying the extra weight, and here’s why: any time you have extra weight on your body, it is harder for your body to do the same amount of work. This is why overweight people burn more calories than those who weigh less while doing the same amount of exercise. Your body has to work harder to move that extra weight, which means you burn more calories.
Your dumbbells aren’t body fat, but your body is still 10 pounds (because you are holding two 5 pound dumbbells) heavier than normal, so your body will burn a few more calories moving that extra weight. Also, any exercise burns calories, so the extra arm exercises are going to burn extra calories, as well. Those exercises would burn calories even if you are standing still.
The more weight you hold, the more calories you will burn. If you lugged a backpack full of 20 pounds of sand on your walks, you’ll burn twice as many extra calories than when holding the 10 pounds worth of dumbbells.
If you want to know how many more calories you a burning, add 10 pounds (or however much extra weight you are holding) to your body weight and punch it into a calories burned calculator and see the difference.
Before you go dragging around 25 pound dumbbells to up your burn even more, consider buying a weighted vest. With a weighted vest, the extra weight is evenly distributed close to your body, so it is a safe and comfortable way to add 20-30 pounds to your workout.
NOTE: don’t use ankle weights on walks/runs to increase your intensity, especially if running. The added weight at the bottom of your limbs can wreck your knees.