Humans have a “2nd heart” in their calves that helps pump blood back to the heart, this muscle must stay active to avoid blood clots.
The calf muscles, especially the soleus and gastrocnemius, function like a second heart by helping push blood from the legs back to the heart.
When they contract, they compress the veins, and the one-way valves inside those veins keep the blood moving upward. This action supports venous return and helps stop blood from collecting in the lower legs. These same contractions also compress lymphatic vessels and push lymph fluid upward against gravity, helping the body maintain fluid balance in the legs. The combined effect on blood and lymph reduces pooling and can ease the heaviness or swelling that often follows long periods of sitting or standing.
If you are inactive for long periods, this calf pump becomes less effective, which can increase the risk of deep vein thrombosis (DVT), varicose veins and long-term venous disorders.
Because the soleus is a highly fatigue resistant muscle, it’s particularly important for sustaining this pumping effect over extended periods.
Consistently strengthening and stretching the calves with exercises such as calf raises and calf stretches (see exercises 5 & 6, in the Leg day section) improves their performance, supports healthy circulation, can help reduce blood pressure, and offers protection against blood clot formation.
A Simple Evening Habit
Raising your feet by standing on your toes (calf raises) twenty times before bed is a quick and easy way to activate the same calf-pump after a day of sitting or standing and may ease the feeling of heavy or swollen legs by the next morning.