Cold exposure, particularly to the distal extremities (fingers and toes) results in profound vasospasm, limiting blood flow. As the fingers and toes are re-warmed, many people experience significant pain that is described as severe as grasping broken glass. Why does this happen? Let's take a look and see if we can describe why fingers and toes can hurt so much upon re-warming.

Raynaud's disease - prevention and treatment

Cold exposure, particularly to the distal extremities (fingers and toes) results in profound vasospasm, limiting blood flow.  As the fingers and toes are re-warmed, many people experience significant pain that is described as severe as grasping broken glass.  Why does this happen?  Let's take a look and see if we can describe why fingers and toes can hurt so much upon re-warming.

From a physiological standpoint, your body is a smart manager of cold weather.  Your body views every experience of cold exposure as a potentially life-threatening situation.  When exposed to cold weather, your body's sole responsibility is to maintain it's core temperature.  Deviations in core body temperature to 35 C (95 F) will result in symptoms of fatigue, lethargy, drowsiness and a confused state.  If blood was to be circulated through cold hands, the blood would be chilled and returned to the body core, lowering core body temperature.  Your body's natural defense mechanism is to shut off blood flow to the coldest (most distal) parts of the body.  In medical terms, this loss of blood flow is called peripheral vasospasm.

The hypothalamus is the portion of your brain that regulates your body temperature.  When your hypothalamus recognizes that you've returned to a warmer environment, it responds by increasing the blood flow back to the hands.  This response in increased blood flow is called reactive hyperemia.  In cases where people experience pain in the fingers and toes, the pain is due to the peripheral vasospasm and reactive hyperemia clashing.  Pain results from the stimulus of the nerves found in the small arteries (arterioles) of the fingers and toes.  It's as if the arterioles didn't get the message from the hypothalamus that the threat is over.  Peripheral vasospasm persists while reactive hyperemia tries to push new, warm blood into the fingers and toes.  There's one warning signal that we all recognize when our body is threatened and that's pain.  And in the case of pain upon warming, your body is simply saying there's a critical issue here.  In a way, your body is warning you to just not do this again.

Treatment of Raynaud's with L-Arginine Cream

Prevention is key to preventing cold exposure and post-cold exposure pain.  Keeping the hands and feet dry with a drying agent is important.  Body powder and drying agents are essential, particularly in cases of generalized hyperhydrosis.  One amazing tool that can be used to keep that hands and feet warm is warming creams made of L-Arginine.  

And don't forget to wear your hat.  Why?  Because your mom said so.  And she was right.  The majority of heat loss in cold exposure is heat loss from the head.

Jeff

Jeffrey A. Oster, DPM
Medical Advisor
Myfootshop.com

Updated 12/27/19