Your heart beats nonstop to deliver blood to every part of your body, but it gets an assist from another pump that probably needs activating as you’re reading this right now.
The calf muscles are your “second heart,” squeezing veins in the lower legs to help return deoxygenated blood from the feet back up towards the chest, the Cleveland Clinic notes.
The “second heart” only starts pumping when your legs move. That’s a problem when many people sit or stand for hours at work.
“The blood flow back to the heart has to fight the force of gravity, which keeps everything down. So without a natural pumping mechanism, there’s no way for the for the blood to get back to the heart,” Dr. Teresa Wu, a vascular medicine physician at the Cleveland Clinic in Ohio, tells TODAY.com.
“We need the blood to go up the leg to return to the heart … so the calf muscle pump is really important.”
How the ‘second heart’ works
Every time the calf muscle contracts, one-way valves inside the leg veins open and blood gets pushed upwards towards the heart; when the calf muscle relaxes, the valves close, which prevents blood from flowing backwards into the legs, Wu says.
When people spend a lot of time sitting or standing, pressure can build up in the veins and damage the valves over time, making them “leaky” and causing more blood to pool in the legs, she notes.
Losing the calf muscle pump function can lead to symptoms of chronic vein disease, such as swelling, leg tiredness and varicose veins. The worst medical complication could be a blood clot, which is rare but can happen when people sit for many hours on a long flight without getting up, Wu adds.
An inactive "second heart" may also lead to "sitting disease," a term that describes how sedentary behavior can negatively impact health, researchers reported in the journal Biofeedback. Sitting too much may raise heart disease risk, the American Heart Association cautions.
But excessive standing seems to be bad, too. The standing desk movement actually increased the rates of venous issues because people were just standing at their desks without moving, says Dr. Sharonne Hayes, a cardiologist and professor of cardiovascular medicine at the Mayo Clinic in Rochester, Minnesota.
“A lot of people got varicose veins for the first time or blood clots for the first time,” Hayes tells TODAY.com.
“Standing is almost in some ways worse than prolonged sitting for veins.”
How to activate the ‘second heart’ with 1 step
Just walk — take a walking break as often as you can, but at least once or twice an hour, both experts say. “It’s to get that calf muscle pumping,” Hayes notes. “Keep moving.”
“I would just encourage everybody to walk as often as they can, especially if you have a desk job or a standing job,” Wu adds.
If you’re on a plane or stuck at your desk at work and can’t get up, do toe raises — flex the foot up and down — which is the closest you can get to mimicking the motion of taking a step, Wu says.
Elevating the legs can also be helpful, especially for people who already have symptoms of chronic vein disease, she adds.
It has to be over the level of the heart, so propping legs up on a stool in front of you won’t do much. It's best to lie in bed with your legs up on pillows or lie on a couch with your legs resting on an armrest.
Wu recommends elevating the legs for 15 to 30 minutes at nighttime for people who experience bothersome swelling. Compression socks can help, too, for people who sit or stand a lot.
And remember: We are meant to move. "Use those legs to activate the calf muscle pump," Wu says.