By Stephen Green

Promising recent scientific research in “classical conditioning therapy” indicates that Raynaud’s patients may be able to train themselves to avoid the painful spasms that occur when they’re exposed to cold temperatures. 

The approach blends two areas of research relating to improving hand circulation. The first part is based on the groundbreaking work by Dr. Dennis Grahn and Dr. Craig Heller, researchers and professors at Stanford University, who spent their careers studying the phenomenon of circulation effects in people’s hands. They spent time investigating how warm environments improved hand circulation while cold environments collapsed it. Their work explains how Raynaud’s patients can increase the circulation in their hands by placing them under warm water—easing their pain and reversing the hallmark blue, white and red color changes associated with Raynaud’s.

Classical Conditioning
Could Raynaud’s patients be conditioned so that when they encountered cold, their hand circulation opened up?

As a Raynaud’s sufferer myself, I experienced this practice. Years ago, I was working outside on a winter work crew.  On every lunch break, my first task was rushing to a sink with warm water and holding my hands under it to bring color and feeling back to my fingers.  Everyone who has to deal with Raynaud’s knows that running your hands under warm water is an effective way to bring back circulation to cold hands. 

Drs. Grahn and Heller found that the small capillary blood vessels in a person’s palms are excellent places to add heat into a person’s body.  Also, they found that when a person’s palms are kept warm at body temperature (around 98 degrees Fahrenheit) their capillaries dilate, opening up good hand circulation.  Their research showed that when hand temperatures dropped more than five degrees below body temperature, capillaries would begin to constrict, limiting circulation in the extremities. 

Enter Murray Hamlet, DVM, former Director of the Army’s Natick Cold Research Division lab. Dr. Hamlet looked at classical conditioning experiments from the U.S. Arctic Medical Research Laboratory and wondered if he could use this type of technique to help people with Raynaud’s circulation problems. Could Raynaud’s patients be conditioned so that when they encountered cold, their hand circulation opened up? The good news is that the answer is yes. He and many other researchers have found that improvements in circulation can be trained.

The Hamlet method is simple.  A person sits in a warm room with warm hands. The person then moves into a cold place (ideally 32⁰F) for ten minutes. They wear only light clothing so that their body definitely knows that they are in a cold place. Their hands are kept warmed to temperatures between 109- and 113-degrees Fahrenheit. The person then comes back into a warm location, and keeping their hands warm, they let their bodies return to a comfortable temperature.  

In Dr. Hamlet’s experiment, this was repeated three to six times on a given day, with a day off taken in-between session days so that a person’s body could rest and internalize this reaction. The experiment called for 50 of the 10-minute sessions.

All subjects had measurable improvement in finger temperatures of at least 2 degrees Fahrenheit when exposed to cold. Dr. Hamlet reported that improved responses to cold lasted for months to years, and when a subject’s cold resistance began to fade, a reduced number of cold temperature training sessions would be enough to refresh cold resistance levels.

Various academic groups have repeated this experiment in recent years, with similar positive results. Jared Jobe, Ph.D., published a paper on this method as a form of home treatment for Raynaud’s in 1985.  M.J.D. Goodfield, M.D. expanded this technique to Raynaud’s phenomenon occurring in systemic sclerosis patients, publishing in the British Journal of Dermatology in 1998.  Ingela Carlsson published her successful results with this technique in the Scandinavian Journal of Plastic and Reconstructive Hand Surgery in 2003.  Most recently, in 2016 a group led by Tone Vaksvik, O.T., Ph.D., repeated the classical conditioning experiment using 18 focused therapy sessions, with three cold exposures during each rather than 50 individual sessions.

If classical conditioning works, why doesn’t it get more exposure?  To begin, it is difficult to sit through 18 sets of cold temperature training sessions. Sometimes the outdoor weather doesn’t cooperate in providing cold temperatures for training.  Sometimes motivation fades.  Sometimes time constraints make it difficult to do cold weather exposure sessions before work in the morning.

For at least 50% of patients, calcium channel blocker drugs are helpful, possibly reducing the motivation to commit to the training. In support of classical conditioning, however, there are two great benefits. First, it does not require drugs, as it relies on reconditioning a body’s natural responses.  Secondly, classical conditioning avoids the ongoing expense and potential side effects of prescription drugs.

A classical conditioning routine is easy to set up. Modern heated gloves with lithium batteries and modern temperature control circuits can easily replace the cumbersome tubs of warm water used in earlier experiments. The best gloves are those with stable temperature settings because hand circulation decreases if temperatures get too hot. Still, any form of temperature-stable hand warmers will do. 

Current modern hand warmers allow a person to perform these classical conditioning activities at their own schedule and pace. If you live in a colder climate and it takes you at least 10 minutes to drive to and from work, there are two training opportunities right there. All that is required is a freezing morning, light clothing and gentle 110⁰F warmth for a person’s hands. For people who cannot or do not want to take calcium channel blocking drugs, classical conditioning has shown excellent potential for helping people live well with Raynaud’s phenomenon.

Editor’s Note: Mr. Green is an engineer who enjoys helping with challenging health issues. He is also a Raynaud’s patient.  He can be reached at

Other articles for reference:

Simple Method Found to Warm Cold HandsNew York Times

Induced Vasodilation as a Home Treatment for Raynaud’s

Keeping Warm: A discussion with Dr. Murray Hamlet on Cold Weather PhysiologyScience in the News, Harvard University

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