Weight Loss

I lost about 25 pounds since I started swimming over 2 years ago. Actually most of the loss occurred in the first 6 months. According to Dr. Phil Whitten, the swimming guru, author and scientist, many of the studies comparing running to swimming used fast runners versus slow swimmers, thus leading to skewed results. I don't agree with the large muscle versus small muscle theory that would favor runners. If your heart and lungs are telling you that you are working hard, then you're getting the job done no matter what exercise you're doing. I also don't buy the "thermodynamic" argument that swimmers are at a disadvantage because the water is an infinite heat sink. The temperature rise experienced by runners is due to an accumulation of waste heat, not greater calorie consumption. Swimming utilizes both aerobic and anaerobic energy pathways. The more intense the effort, the greater the anaerobic component. Roughly speaking, the total calorie consumption per unit time varies with the perceived intensity level, and that is the determining factor. Some argue incorrectly that lower intensity aerobic is better, but that is a misconception due the the fact that aerobic exercise derives a higher percentage of energy from fat. However, it is total calories that matter. The fact that running is weight-bearing is irrelevant to the energy equation. Your body's chemical pathways don't know or care whether gravity or a viscous fluid is the source of mechanical resistance. (Your joints, on the other hand....) The appetite-suppressing effect of elevated body temperature is utterly marginal, i.e., it shouldn't affect your decision whether to choose swimming or running. If you are doing either one regularly, you are waaaay ahead of the pack.

I lost about 25 pounds since I started swimming over 2 years ago. Actually most of the loss occurred in the first 6 months. According to Dr. Phil Whitten, the swimming guru, author and scientist, many of the studies comparing running to swimming used fast runners versus slow swimmers, thus leading to skewed results. I don't agree with the large muscle versus small muscle theory that would favor runners. If your heart and lungs are telling you that you are working hard, then you're getting the job done no matter what exercise you're doing. I also don't buy the "thermodynamic" argument that swimmers are at a disadvantage because the water is an infinite heat sink. The temperature rise experienced by runners is due to an accumulation of waste heat, not greater calorie consumption. Swimming utilizes both aerobic and anaerobic energy pathways. The more intense the effort, the greater the anaerobic component. Roughly speaking, the total calorie consumption per unit time varies with the perceived intensity level, and that is the determining factor. Some argue incorrectly that lower intensity aerobic is better, but that is a misconception due the the fact that aerobic exercise derives a higher percentage of energy from fat. However, it is total calories that matter. The fact that running is weight-bearing is irrelevant to the energy equation. Your body's chemical pathways don't know or care whether gravity or a viscous fluid is the source of mechanical resistance. (Your joints, on the other hand....) The appetite-suppressing effect of elevated body temperature is utterly marginal, i.e., it shouldn't affect your decision whether to choose swimming or running. If you are doing either one regularly, you are waaaay ahead of the pack.