 [ Symptoms ] as a teen how can exercise affect my weight [ Disease ] because exercise helps use up oxygen it causes your body to burn stored fat and helps you maintain a normal weight for instance if you walk 4 miles a day four times a week you can burn about 1 600 calories or nearly half a pound a week if you do not change your diet at all and keep walking the same distance over six months you will lose 12 pounds walk the same distance for a year and you will drop 24 pounds the neat thing about exercise is you do not have to do it all at one time after all not many teens have time to walk 4 miles after school but you can do 4 miles in short bursts throughout your day here is an idea of how to work that much exercise into your daily regimen take a 1 mile walk on a treadmill before school then take a 1 mile walk around the track during school lunch period take a 1 mile walk after school with friends or the family dog take a 1 mile walk on the treadmill while watching your favorite show before dinner if you stay with the walking program you will see benefits with weight loss muscle strengthening and definition stronger bones a lower heart rate better mood an improved complexion