If you’ve ever glanced down mid-run and noticed your fingers looking like sausages, you’re not alone. Hand swelling, or exercise-induced edema, is a common but often overlooked phenomenon among runners. While it’s usually harmless (but often feels very unpleasant), understanding why it happens and how to prevent it can make your runs more comfortable.
Why does it happen?
The main reason for hand swelling during exercise is fluid redistribution. When you run, your body directs blood flow to the working muscles—mainly your legs—to deliver oxygen and remove waste products. This shift means less circulation in the extremities, which can cause fluid to pool in the hands.
Other contributing factors include:
Increased blood vessel permeability: Exercise causes capillaries to expand, allowing more fluid to pass into surrounding tissues.
Gravity and arm position: Running with your arms bent at 90 degrees and swinging naturally may reduce circulation to the hands, leading to pooling.
Electrolyte imbalance: Sweating depletes sodium and other electrolytes, which can affect fluid balance and contribute to swelling.
Mild lymphatic backup: The lymphatic system helps regulate fluid levels, but repetitive motion and muscle contractions can sometimes cause a temporary slowdown, leading to puffiness.
When should you worry?
In most cases, swollen hands during a run are nothing to worry about and resolve shortly after stopping. However, if you experience additional symptoms like severe swelling, tingling, numbness or difficulty moving your fingers, it’s worth checking in with a doctor. These could indicate an underlying issue such as hyponatremia (dangerously low sodium levels) or circulation problems.
How to prevent it
While you may not be able to stop hand swelling entirely, a few small adjustments can make a big difference. One of the simplest fixes is to keep your hands moving—wiggle your fingers, make a fist, then release it. This helps circulation and prevents fluid from pooling. If you’re carrying a water bottle or other gear, be mindful of your grip. Holding on too tightly or for too long can restrict blood flow, so switch hands periodically and keep your grip relaxed.
Hydration also plays a role, but drinking too much plain water without replacing electrolytes can actually make swelling worse. On longer runs, consider a sports drink or electrolyte supplement to help maintain balance. Arm position matters, too. Every so often, try raising your hands above heart level to help redistribute fluid. And don’t forget your clothing—tight wristbands or restrictive sleeves can make swelling more noticeable, so opt for looser, moisture-wicking gear that won’t cut off circulation.
The bottom line
Swollen hands during a run might look strange and feel strange, but for most runners, it’s a harmless quirk of the body’s natural response to exercise. By staying mindful of hydration, circulation and arm movement, you can reduce discomfort and keep your focus on the miles ahead.
