Calories Burned During Exercise
Part 1 of 2: Walking
Once you’ve tried all the diet gimmicks, and all the quick weight loss diets that promise to “incinerate,” “melt,” “blast,” and “annihilate” those unwanted pounds, and you still weigh as much or more now than before (except in the wallet), it’s time to come back to what really works; no fancy power-words that excite you to buy the product – just what works.
And what works is to lose between one and two pounds per week by adjusting your daily calories via a combination of diet and exercise.
One pound of fat equals 3,500 calories. By creating a 500 calorie negative energy balance, you will lose about one pound per week. Losing between one and two pounds per week is considered a safe weight loss, and will be primarily from fat. Weight lost from rapid weight loss diets is mostly from muscle and water (muscle weight is about 75% water), and not from fat.
It is always easier to create a calorie deficit when combining energy expenditure from exercise with caloric restriction in the diet. Indeed, the more calories you burn during exercise, the fewer calories you have to lose from food. This means that not only will you gain the health benefits of exercise, there is less sacrifice to be made at the dining room table; win-win.
Both cardiovascular exercise and strength training can make significant calorie-burning contributions to your weight loss program. This article is about calorie expenditures from walking, and is Part 1 of a two-part series. Part 2 will be about strength training, and will follow soon.
Let’s begin with the obvious: you already know how to do it. And you don’t need to be heavily invested in special equipment – just a good pair of walking or running shoes. Also, you can walk anywhere, so you’re not tied to a particular location, or to any specific equipment. On a business trip or vacation? Walk wherever you are. Like an indoor environment? Walk on a treadmill or an indoor track. Prefer an outdoor environment? Duuuhh! Walking can also be a companionable activity – something that you can do either alone or with someone else.
Walking is the preferred mode of aerobic exercise for anyone with low functional capacity, as well as anyone who has been leading a sedentary lifestyle – especially those over age 60. It is also the preferred aerobic exercise for those who are significantly overweight. In addition, walking is mentioned in health literature as either a recommended or the recommended aerobic exercise mode for those dealing with asthma, coronary artery disease, COPD, diabetes, and hypertension.
Health benefits associated with walking include reduced blood pressure, improved lipid profile, reduction in body fat, reduced risk of heart disease and cancer, and an overall improved feeling of well-being.
And finally, if you’ve tried exercise programs before, only to abandon them later, walking has the highest stick-with compliance rate of all exercise modalities.
Walking vs. Running
First, let’s understand the differences between walking and running.
Force impact and injury
Jogging is just a slow form of running, but walking is not a slow form of jogging. The essential difference between the two is that during jogging/running there is always a point during mid-stride when both feet are off the ground, whereas with walking, one foot is always on the ground. This means that there is a huge difference in the force impact between the two modalities.
During walking, one foot or the other supports 100% of the walker’s body weight with each stride, but not more. During running, due to the effect of gravity, each foot strikes the ground approximately 800 times per mile with a force which is roughly the equivalent of one-and-a-half times body weight. In fact, with some runners, force impact can be as much as four times body weight.
This means that assuming dry, cushioned socks and proper fitting shoes, walking is essentially injury free. Absent these precautions, the worst you’re likely to get from walking is a blister on your foot.
Running, on the other hand, too frequently leads to injuries such as runner’s knee, shin splints, and plantar fasciitis, and can also cause problems in the hips and low-back. Imagine repeatedly hitting a telephone pole with a baseball bat for 30 to 60 minutes on most days of the week. Yes, your hands will become sore, but more importantly, you will eventually experience injuries to your wrists, elbows, shoulders, and neck as a result of force impact being absorbed and distributed along that part of your musculoskeletal system. This is analogous to the force impact created during running being absorbed and distributed along the musculoskeletal system above the feet.
There is a common misconception that walking and running each use the same number of calories. This is not true at the speeds that real people walk, even during aggressive fitness walking.
Generally, walking is considered to include all speeds below 6 miles per hour. Jogging speed is between 6 mph and less than 8 mph, and running speed is 8 mph and faster. Stride length and other factors will determine the actual differences on an individual basis, but these are good typical speeds for each modality.
Back to the same-calories misconception. Two things to know:
First, there is a point during which walking burns jog-like calories. But that requires a walking speed of 5 mph (1 mile in 12 minutes), which is very, very difficult to achieve, and especially difficult to sustain for a productive period of time.
Second, intensity matters with respect to caloric expenditure. Example: a 175 pound person walking at a casual stroll pace of 2 mph for 40 minutes will burn about 106 calories. But if the same person ramps up their speed to 3.5 mph, the caloric expenditure jumps to 201 calories, and further increasing speed to 4 mph will burn 265 calories – all during an identical 40 minute period.
Using the American Council on Exercise (ACE) physical activity calculator, I have created a chart which shows how many calories people of different body-weights - from 175 pounds to 250 pounds - can expect to burn by walking at any of five different speeds, for each of 20, 40, and 60 minutes. These calculator-driven results are subject to variables, so consider the information as a guide only.
Click the following link to open the chart. Also, be sure to scroll down to the second page for additional information.
Another useful approach to gauging your intensity is via a scale known as Ratings of Perceived Exertion, or RPE. There are two main RPE scales. The original version rates exertion on a scale of 6-20. The revised version uses a 0-10 scale. I have created my own version, the Modified RPE, which I believe resolves some of the incongruities of the other versions.
For additional information about exercise intensity, see my earlier article “Exercise: Measuring Intensity,” under the Exercise heading in the blog section of this website.
Creating Your Personal Walking Program
Okay, you're going to start walking. Great! That's the easy part. Now, let's focus on outcomes and how to achieve them.
As already mentioned, intensity matters. Intensity and duration are what creates the exercise workload. As you've seen from the chart, walking at 3.5 miles per hour burns more calories than walking for the same amount of time at a slower speed, and fewer calories than walking for the same amount of time at a faster speed. So, if weight loss is your goal, speed matters.
Time matters, too. If you walk at a steady pace for 30 minutes, you will burn more calories than walking at the same pace for 20 minutes, etc.
And let's not forget frequency. If weight loss is your goal, then you should plan on fitness-walking most, if not all, days of the week.
Good so far.
Now comes the tricky part: Over time our body systems adapt to challenging workloads by becoming stronger and more efficient at executing the exercise task. If you stay at the same speed and duration once you've adapted to it, you will stop making progress; it's what's called hitting a plateau.
So while walking in and of itself is good, you need a specific plan to make sure that you're holding aces-over-kings, and not deuces and treys.
What to do?
The best way to avoid plateaus, or to break through them, is by a dynamic technique known as progression. As the name implies, progression is taking your training to the next step, in a logical and orderly fashion.
With regards to walking, an effective progression plan increases walking duration at the present speed before increasing speed. Repeat: increase time before increasing speed.
A beginner-level exercise walker should just start walking, or like Nike says, just do it. Somewhere between week-one and week-six, start following a plan. For instance, use your car's odometer to pre-measure a walking route, noting 1/4, 1/2, 3/4 and 1 mile landmarks.
Next, at an RPE of 4 ("Somewhat Hard"), time yourself walking each of your landmarks. If your stamina is limited, be careful not to out-walk your return, meaning don't walk a mile out if you can't walk a mile back. This is why you should pre-measure your route to include the intermediate landmarks, and not just the one-mile mark.
The initial conditioning phase should last between four and six weeks. After about two weeks, gradually begin increasing your time, while staying at the same speed, or the same RPE.
An overall long-term objective might be to walk for 45 minutes at a sustained pace of 4 mph, which is a 15 minute mile. Along the way to achieving this objective you will have progressed through various durations, and will have incrementally increased your speeds.
Advanced Training Techniques
Once you have achieved your long-term goal, you continue to prevent and defeat plateaus - or just add some variety - by introducing hills into your routine, or by engaging in advanced speed drills, such as fartleks and intervals.
And in case you haven't already guessed, any time you increase intensity, you may need to reduce your session time until you become conditioned for the new workload. And just like before, gradually build your time back up to where it was. And the progression scheme continues.
Fartlek is a funny-sounding Swedish word that means "speed play." A fartlek routine uses intermittent work and rest periods throughout the session. A typical fartlek drill would be to walk at a brisk, sustainable, but submaximal pace. Periodically, pick a target up ahead - a signpost, a mailbox, the blue car - and walk as fast as you can until you reach the target, then reduce your speed back down to your brisk walking pace. Note: the submaximal pace in fartlekese is called "rest," but it is only rest in the context of it being a sustainable pace, whereas the "work" segments are maximum efforts. Work segments are of short duration, and there is not a pre-planned work-rest scheme.
Intervals are like fartleks, but you time each phase. A typical interval session would be continuously alternating between, say, 90-seconds rest and 30-seconds work. As you become proficient at intervals, the work period becomes longer and the rest period becomes shorter, such as 60-seconds work, 60-seconds rest.
Because fartleks are more ad hoc, you don't need to time the segments. Intervals, on the other hand, are timed. You can use a stopwatch, or a chronograph wristwatch that has a stopwatch or lap counter feature.
As fartleks, and especially intervals, are more intense than steady-state walking, don't be surprised if you can't last as long as you're accustomed to. This is natural, and like all other training routines, your total times will improve with practice, and your work-rest segments will improve work-wise as well.
Furthermore, interval training offers really great results in shorter times than steady-state programs. Because interval training is harder, the sessions are generally shorter anyway.
Warm-up and Cool-down
As with all exercise programs, the main objective of fitness walking is to create a temporary increase in heart rate and a challenge to body systems (muscles, lungs, etc.), which over time will lead to permanent beneficial changes in metabolism, all of which leads to an overall fit, leaner, better functioning, and more attractive body.
Because of the stresses that you subject your body to during exercise, it is very important to perform a proper warm-up before beginning your routine. A five minute warm-up will warm your muscles, making them more pliable, which allows them to move with greater fluidity, and with less chance of injury. A warm-up also psychologically prepares you for the physical stresses you are about to encounter.
Your pre-exercise warm-up for fitness walking should consist of five or more minutes of walking at a slow, normal pace, followed by a few minutes of gentle stretches for your Achilles tendons, calves, and low-back muscles. Hold each stretch for 20-30 seconds, and remember to stretch after the warm-up, not before.
A proper cool-down is at least as important as the warm-up, and perhaps more so. Following exercise, blood tends to pool in the lower extremities, and blood pressure may also be low. A proper cool-down helps redistribute pooled blood, and assists in reestablishing homeostasis, which is when the body and its systems are in balance. This has implications for post-exercise muscle cramping, blood pressure recovery, and reduction in elevated hormones, such as norepinephrine, which can affect cardiac rhythm.
The post-exercise cool-down is the same as the warm-up: walk at a normal pace for at least five minutes, until your heart rate is close to normal, or at least no higher than 18-20 beats per 10-seconds.
Follow the cool-down with the same gentle stretches you performed during the warm-up. Amongst other things, post-exercise stretching allows muscles to release waste products that have built up during the stress of exercise, helping to prevent or lessen muscle soreness later.
By the way, your warm-up and cool-down does not count as part of your timed exercise routine.
And Finally . .
Good luck with your walking program. It is a great way to exercise, with lots of benefits. It is one of the safest forms of exercise, and one that you can continue to do well past the age that most other forms of exercise are not possible.
And don't let anyone tell you that walking is not for serious exercisers. I used to run 6 miles a day. Now I am a dedicated fitness walker, and my knees are grateful.