The imbalance between the capacity of ones lymph transport system and the lymph load is what causes lymphedema in the very basic sense.
The lymphatic system present in the human body not only filters out waste products but also helps maintain fluid balance. This results in a human being not being dehydrated or edematous. Also the extracellular proteins are brought back to central circulation via the lymphatic vessels. This is because diameters of these protein molecules are too big to fit into the openings in the vein walls. The opening of lymphatic vessels is adequate for this.
So to summarize this disease is not just a problem of excess water being retained in tissues but also of excess protein being retained in tissues too.
So the question arises, how is this connected to exercise?
The answer is that when we review the acute and chronic effects of exercise we see that it is helpful to know about how a limb at risk or a lymphedematous limb will react to exercise.
Reactions to exercise that can be categorized as acute include Increases in:
- Heart rate.
- Stroke volume.
- Cardiac output.
- Blood flow to active muscles.
- Systolic blood pressure.
- Arteriovenous oxygen difference.
- Ventilation.
- Oxygen uptake.
In addition to these increases there is a decrease in blood pH and plasma volume.
Going beyond acute, chronic reactions to exercise include.
- Changes of biochemical nature in skeletal muscles.
- Decrease in the resting heart rate.
- Decrease body fat and blood lipids.
- Decrease in density and strength of bone and connective tissue.
When a person exercises more blood is directed to muscles. When a person is resting, only twenty one percent of cardiac blood output goes to the muscles, which during exhaustive exercise reaches to as high as eighty eight percent. When the body heats up more and more blood is directed towards the skin so as to carry heat away from the body core.
Now we know that lymph transport should be equal or greater than the lymph load. When a person exercises their muscles require extra blood so that they can provide the oxygen required for muscles to do the exercise work.
We already know that extra blood flow translates into extra water remaining in the extracellular spaces and thus will need transport via the lymphatic system.
Exercise is thus beneficial for lymphedema patients but one should take care about how much exercise they do as this differs from individual to individual.