Originally Posted by
Mobile 155
Slow cycling uses about 31 calories per mile. Oatmeal for breakfast is about 150 to 180 for a small bowl. No sugar no butter no milk. It takes 4 to 6 miles just to burn those 150 to 180 calories. Somewhere I have read the average American diet is 2000 calories or more. At 12 mph it will take closer to 8 to 10 hours to burn off calories at 12 mph. And considering 12 mph isn’t even aerobic I might take longer.
Using your figure of 31 kcal/mile, the person riding at 12mph for 8-10 hours would be burning about 3000-3700 kcals which puts him at a severe calorie deficit if his diet is only 2000 kcals. And an average male may have a basal metabolism rate of about 1700 kcal/day (i.e. uses that many kcals just to maintain essential body functions and temperature). So his total calorie output (assuming no other significant physical activities) would be about 4700 - 5400 kcal. vs. an intake of only 2000 kcal. - not a sustainable level of exertion at that dietary intake.
And what do you mean by "isn't even aerobic"? Any muscular movement requires oxygen from the air. If it's a very intense exertion, such as the finishing sprint in a bike race, it uses up oxygen faster than the lungs can replenish it and is deemed to be anaerobic and leaves the participant gasping for breath. Exercise at lower levels is aerobic since the lungs can maintain reasonably constant levels of oxygen in the blood.