Aerobic exercise is believed by many scientists to be the single best predictor of weight maintenance. You can lose weight without exercise by reducing your caloric intake enough so that you burn more calories than you consume, but it takes a regular dose of exercise to keep your weight off. How much is not clear, but somewhere between 30 and 40 minutes of vigorous exercise several times per week, to 45 to 75 minutes of moderate intensity exercise five or more days per week is probably about right. Your mileage will vary, and so once you get to the weight that you want to be at you'll need to experiment with different amounts of exercise until you find the one that works for you. The American College of Sports Medicine recommends that overweight and obese individuals progressively increase to a minimum of 150 minutes of moderate intensity physical activity per week, but for long-term weight loss, overweight and obese adults should eventually progress to 200 to 300 minutes per week of moderate-intensity physical activity. These are general guidelines, and so again, you need to experiment to see what works for you.
Your heart rate rises during aerobic exercise. It can rise from 70 beats per minutes (bpm) at rest to as high as 170 bpm or even higher during exercise, depending on the intensity of the exercise, your fitness level, your age, and other factors. Whether you're training is aerobic or anaerobic is determined by the intensity of your workout, and monitoring the intensity is the key to know which one you're doing.
Your weight x distance = energy used walking. Time does not matter as much as distance. If you speed up to walking a mile in 13 minutes or less, you will be burning more calories per mile. But for most beginning walkers, it is best to increase the distance before working on speed. A simple rule of thumb is 100 calories per mile for a 180 pound person.
There is also an ever increasing array of affordable home fitness products available, such as steps, skipping ropes (remember to put your breakables a safe distance away), rebounders (rebounding is considered by NASA to be the “most efficient and effective exercise yet devised by man”), dance mats that you can use with your games console and exercise videos so that you can workout with your favourite celebrity.
Aerobic exercise (also known as cardio) is physical exercise of low to high intensity that depends primarily on the aerobic energy-generating process.[1] "Aerobic" means "relating to, involving, or requiring free oxygen",[2] and refers to the use of oxygen to adequately meet energy demands during exercise via aerobic metabolism.[3] Generally, light-to-moderate intensity activities that are sufficiently supported by aerobic metabolism can be performed for extended periods of time.[1] What is generally called aerobic exercise might be better termed "solely aerobic", because it is designed to be low-intensity enough so that all carbohydrates are aerobically turned into energy.
Cancer has claimed over a million lives. A sedentary lifestyle is one of the causes of cancer, and this is where walking every day can help you. Scientists have found that walking can help in weight loss, thereby reducing the risk of cancer. Walking has been found to be helpful for those undergoing cancer treatment by reducing the side effects of chemotherapy (6). It can also lower the risk of breast cancer.

Knowing a bit about the health benefits of walking can also help you stay on track. Not only can walking benefit your heart, bones, and joints, it can also prolong your life. In a 10-year study of 650,000 adults over 40, those who got 75 minutes of moderate activity, like walking, weekly, lived on average, nearly two years longer than their sedentary counterparts. Walkers who logged just over an hour a day gained four and a half years!
As a general goal, aim for at least 30 minutes of physical activity a day. If you can't set aside that much time, try several short sessions of activity throughout the day. Any amount of activity is better than none at all. Even small amounts of physical activity are helpful, and accumulated activity throughout the day adds up to provide health benefit.
It all starts with breathing. The average healthy adult inhales and exhales about 7 to 8 liters of air per minute. Once you fill your lungs, the oxygen in the air (air contains approximately 20% oxygen) is filtered through small branches of tubes (called bronchioles) until it reaches the alveoli. The alveoli are microscopic sacs where oxygen diffuses (enters) into the blood. From there, it's a beeline direct to the heart. 

Whatever your preferred exercise intensity, it’s also important to choose activities that you enjoy and will stick with over the long term. Walking, biking, hiking, dancing, and gardening are all great forms of aerobic exercise that you can easily integrate into your day. After all, aerobic exercise can greatly improve your health even if you perform it in shorter segments throughout the day.

This is a good aerobic workout that also boosts upper body strength — and helps you let off steam. Boxing classes are widely available in many gyms. Some classes involve sparring with a partner — you take it in turns to hold a pad or pads while the other person punches them while wearing boxing mitts. Others involve no mitts or pads, just air punching and other moves that simulate boxing training. You can also use a punching bag either at the gym or in your own home.
As you get started toward the recommended 30 minutes of moderately intense aerobic exercise five days per week, aim to exercise at a level that just lets you keep up a conversation during the activity. If you can get out three or four sentences in a row without gasping for air, it’s a sign that you’re maintaining an intensity that is truly aerobic, meaning aerobic metabolism is supplying the vast majority of your body’s energy, Jonesco says.