By Michael Urti
With the weather finally breaking into more spring like temperatures, getting the dog out of the house for some exercise is important for both you and your pet. It is no secret that exercising daily has a variety of health benefits.
Getting up off the couch and doing something is better than nothing, but is there a minimum amount of work that needs to be done to attain certain health benefits? Also, does walking the dog meet this “minimum threshold” of exercise induced health benefits?
The value of daily exercise cannot be understated. Daily physical activity has been shown to decrease the risk of chronic diseases such as cardiovascular disease, diabetes, hypertension and obesity. According the Surgeon General's Report Physical Activity and Health, significant health benefits can be obtained by including a moderate amount of physical activity on most, if not all, days of the week and additional amounts of health benefits can be obtained through greater increases in activity. Moderate physical activity can be described as a brisk walk for 30 minutes a day or 15 minutes of running.
So there you have it, walking the dog for 30 minutes a day can improve your health. The only problem is that typically, while walking the dog, he/she needs to do his/her business, comes in contact with other dogs, or smells an interesting scent at the base of the fire hydrant that puts your workout on hold. This constant start and stop cycle reduces your ability to elevate your heart rate and train your body to work better. Heart rate during exercise is the best indicator that an exercise modality is adequate at producing health and fitness benefits.
The American College of Sports Medicine recommends that a person exercise three to five days per week at 50 percent to 85 percent of their heart rate reserve (HRR). A person's HRR is a the heart rate max (HRmax = 220-age) minus their resting HR (HRrest). Once the HRR is established we then need to multiply it by the percentage of that value we would like to exercise and add the HRrest to give us our target heart rate. Thus, for a 30-year-old person wanting to exercise at 50 percent of their HRR with a HRrest of 60 bpm, their THR would be (190-60) x .5 + 60 = 125 bpm. As we can see, for walking the dog to be an effective stimulus for this person, they need to reach and maintain a HR of 125 bpm throughout the walk, which should be 20-30 minutes in duration. With the start and stop tendencies of a typical dog walk, this HR can be difficult to achieve.
Now what about weight loss? Can walking your dog help you burn calories and shed some unwanted pounds? Well, because you are moving you are burning some calories, but the actual amount is dependant upon the speed of the walk, the hills and the person's body weight. For a person walking at 3.75 mph at a 0 percent grade he/she is using 3.9 metabolic equivalents of energy or METs. One MET is the amount of oxygen you use at rest. So for a 68 kg (150 pound) person walking at the above pace they are using 13.6 mL.kg.min of O 2 . After converting to liters of O 2 per minute and doing the math, the total calories burned per minute at this pace is ~4.6 kcal. In 30 minutes, this person burned 138 calories.
Essential to weight loss is the concept of caloric deficit, which means the calories burned are in excess than the calories taken in. Also, for a person to lose 1 pound there must be a caloric deficit of 3,500 calories. This seems like a lot but when combined with diet a caloric deficit of 500 calories per day for seven days results in weight loss of 1 pound a week. This deficit can be obtained by cutting calories and burning calories via exercise. Our previous dog walking example shows us that we need to substantially increase the duration or intensity and/or cut about 400 more calories for weight loss of 1 pound a week to occur.
Dog walking does serve a purpose in being active, but as a primary means of improving cardiovascular function, improving fitness and losing weight, the benefits are minimal compared to other exercise types.
