Many pathological conditions cause hand swelling, like carpal tunnel syndrome, Raynaud’s disease, reflex sympathetic dystrophy, thoracic outlet syndrome or trauma. However, healthy hikers without any of these issues often report swollen and painful hands when hiking. Commonly known as sausage fingers, this swelling is usually temporary but can be uncomfortable for some. What causes it and how to prevent it is a bit of a mystery.
Research into idiopathic hand swelling (that which occurs without a known cause) is sparse. A literature review found only one study on the topic in which researchers in Brazil surveyed participants in a community walking event(1). Of the 1009 subjects who completed the survey, nearly 25% experienced hand swelling after walking. In the study, females complained of the swelling twice as often as males. Most reported that the swelling went away after an hour or so, but just over 10% described their swelling as persistent.
Most people walk with their arms swinging by their side. This natural rhythm appears to occur with minimal a metabolic cost. In fact, it seems to require more energy to try to hold arms still while walking than to let them swing freely(2). Arm swing also appears to help decrease ground reaction forces felt in the lower body, making it an effective strategy to help take the load off knees and hips(2). Because the arms swing passively during walking, one plausible theory is that fluid collects in the hands from a combination of the centrifugal force experienced as the arms swing and gravity.
Another theory is the effect of exercise on circulation. When exercising, the body shunts blood flow to the muscles that need it most. Therefore, the fingers may suffer from decreased circulation. To adjust for this, the small vessels in the hands called capillaries may dilate to let more blood in, resulting in an influx of fluid into the area.
The same dynamic happens when exercising in the heat. As a cooling strategy, the body moves more circulation to the skin, where the capillaries dilate to move more blood through the area. As a result, hands and feet can become puffy and swollen.
When to worry
Hand swelling is also associated with a condition called hyponatremia. This condition happens when the body has too much fluid and not enough sodium. Hikers experience this life-threatening condition when they’ve over hydrated. While other symptoms usually appear before swelling, it’s always good to know the signs of hyponatremia and remember to let thirst be your guide when determining how much you should drink while out on the trail.
Persistent swelling that doesn't go away several hours after hiking or creeps up the arms may be a sign of a more serious condition. Contact your physician if you experience these symptoms.
5 tips for minimizing hand swelling
The best way to prevent swelling in the hands and fingers is to use muscle contractions to help move the fluid around. Try these strategies to help manage swollen hands:
Remove rings and loosen watches or wrist bands before hiking to limit constricting areas of circulation.
While hiking, open and close your fists several times every 15 minutes to increase circulation and decrease fluid pooling.
Bend your arms at the elbows and swing your hands further through the arc of motion up to shoulder level. Bringing your hands above your heart will help drive fluid back to your core.
Though there’s no research to back it up, using hiking poles seems to help relieve the problem. Theoretically, this makes sense as lifting and moving the poles requires more muscle contractions in the arms than freely swinging does. It also prompts arm movement above the heart, which should help fluid drain out of the hands.
Adjust the fit of your backpack or day pack to ensure that the weight rests on your pelvis and not your shoulders. Pack straps that exert too much pressure on the front of the shoulder can reduce circulation to and from the hands. Therefore, always make sure you can slide your fingers easily under your pack straps.
Reference
1. ISRN Rheumatology. 2011;2011:659695
2. Proc Biol Sci. 2009 Oct 22;276(1673):3679-88