Here's some chilling news about icing an injury:
The next time you or one of your athletes inflame a knee joint, strain a muscle, or twist an ankle during a sporting activity, make certain that you ice the area correctly; inappropriate icing can sometimes make an injury worse rather than better.
'Many athletes spend 20 to 30 minutes continuously applying ice to an aching joint or throbbing muscle, but that can really be counterproductive,' states cryotherapy expert Dr Romain Meeusen of the Free University of Brussels. Meeusen's interest in the sometimes surprising effects of icing the human body began when he was growing up in the northern part of Belgium near Antwerp. As he played with snow as a child, lobbing snowballs into the grey waters of the river Schelde, Meeusen noticed that his bare hands were at first blanched and chilled by the snow but eventually turned bright red and warm, despite their continued contact with the ice-cold snow. The redness and warmness, of course, indicated that prolonged exposure to the icy snow had actually increased blood flow to his hands.
This seemingly strange reaction, in which ice or an application of cold actually increases the flow of blood to a region of the body, represents one reason why Meeusen is concerned about how ice is used therapeutically. After all, one of the goals of cryotherapy is to diminish the movement of blood to the site of an injury, so that there will be less chance of forming a sizeable haematoma (a swollen, painful area containing blood). Since ice can sometimes increase the amount of blood flooding into an injured part of the body, it must be used with caution.
Why it happens
But how can the application of ice enhance the passage of blood into a body region, when everything one's ever learned suggests that ice hampers blood flow? Basically, when body tissues are cooled, nerve cells in the chilled area initially force adjacent blood vessels to constrict, leading to a marked reduction in blood flow in that portion of the body. However, if the temperature of the affected area continues to drop, nerve activity is depressed and the blood vessels begin to open up again, bringing in an onslaught of blood which re-warms the tissues, even though cold is still being applied. Once the nerves heat up (because of the inflow of blood), they shut down the blood vessels again, commencing a new cycle of chilling and warming (like the blanching and then reddening of Meeusen's gloveless hands).
The somewhat surprising increase in blood flow to body parts during cryotherapy (or unprotected activity in cold environments) has been documented by a number of researchers. For example, a classic study on the effects of cold application found that blood flow decreased when body regions were subjected to moderate cooling but increased when colder temperatures were reached ('Hyperemia Following Sustained Contractions at Different Temperatures,' Journal of Applied Physiology, Vol. 137, p. 45P, 1957). Another investigation uncovered a large increase in muscular blood flow as tissue temperatures plummeted ('Vascular Reactions of the Human Forearm to Cold,' Clinical Science, Vol. 17, pp. 165-179, 1958). This flood-of-blood effect is the human body's attempt to thwart severe cold injury in a body part subjected to a chilling stress.
Limit ice applications to 10 minutes
If an injured area is compressed and elevated while it is being treated with ice, the potential increase in blood flow can be partially controlled, but Meeusen still believes it is important to strictly limit the time duration of an ice application in order to minimise the chances that a tidal flow of blood will sweep into an injured joint or muscle. Fairly brief applications of ice also diminish the risk of frostbite-like damage to superficial tissues which are in close contact with the ice. For these reasons, the Belgian researcher and physiotherapist suggests that ice applications should be limited to about 10 minutes or so.
Sceptics who contend that it takes longer than 10 minutes to adequately refrigerate an injured inner region of the body may scoff at the idea of applying ice to a damaged area for such a brief period, but Meeusen's research has turned up some interesting facts which support his contention. For one thing, Meeusen has found that when ice is applied to an injured part of the body for 10 minutes and then removed, the temperature of the skin in the affected area will begin to rise immediately after the ice removal, but the temperature of the muscles and other tissues beneath the skin will actually continue to drop for a few minutes, even though the ice has been taken away.
The continued drop in inner muscle temperature, even after the removal of the ice, occurs because the layer of fat found beneath the skin functions as an insulating material which keeps heat from moving inward to the muscle from the skin and outside world. In addition, the blood vessels leading to the damaged muscle stay constricted for a while in response to the icing (they haven't been chilled enough in 10 minutes for them to open up yet), leading to an actual continued decline in muscle temperature.
Enter the lymphatic vessels
Meeusen's careful research has uncovered another important fact: when ice is applied to a body part for a prolonged period, nearby lymphatic vessels begin to dramatically increase their permeability (lymphatic vessels are 'dead-end' tubes which ordinarily help carry excess tissue fluids back into the cardiovascular system). As the lymphatic permeability is enhanced, large amounts of fluid begin to pour from the lymphatics 'in the wrong direction' (into the injured area), increasing the amount of local swelling and pressure and potentially contributing to greater pain ('The Use of Cryotherapy in Sports Injuries,' Sports Medicine, Vol. 3, pp. 398-414, 1986). If the icing goes on for too long, the lymphatic vessels can actually be nearly obliterated, losing all of their fluid to the surrounding tissues and thus failing to carry excess water away from the injured area (6th European Congress of Sports Medicine, Budapest, Hungary, p. 179, 17-20 June, 1991).
That's why Meeusen has settled on his 10-minutes-at-a-time icing recommendation. With the 10 minutes of ice-induced cooling and a couple of minutes of additional cooling (see above) that occur in a damaged muscle or joint after the ice has been removed, an injured athlete can get a nice chilling effect without running the risk of flushing the site of injury with blood and water or freezing some superficial skin and nerve cells to death.
'Instead of putting ice on an injured area for 20 to 25 minutes, three or four times a day, as many athletes do, it's better to ice the damaged region for 10 minutes immediately after the injury, remove the ice for about 30 minutes, and then reapply it for 10 additional minutes. Repeat this cycle of about two 10-minute icings per hour as often as possible during the first 24 to 48 hours after an injury. Then, use the same technique (two 10-minute icings separated by a 30-minute break) about three to five times a day until the injury resolves itself,' recommends Meeusen.
Be wary of refrigerant gels
What kind of ice therapy should be employed? 'Ice packs are very practical to use, and an ice massage will produce a rapid and profound cooling. Because of their potentially extreme temperatures (as low as minus 20 degrees Centigrade), refrigerant gels should be used with extreme caution: always place a towel between the gel and your skin,' suggests the Belgian researcher. 'Remember that the main effect of 'cooling' sprays is actually the easing of pain; they produce only a temporary chilling of the skin and do not lower the temperature of the deeper tissues,' says Meeusen.
Here's a tip concerning an easy and practical way to apply ice to an injury: simply fill a styrofoam cup with water, place it in the freezer section of your refrigerator, and remove the cup once the water has frozen solid. Peel away the styrofoam around the top of the cup, exposing a solid 'bulb' of pure ice. Massage the injured area of your body with this bulb for 10 minutes, as suggested by Meeusen, and then repeat the massage 30 minutes after the end of this first ice application. Continue in the manner recommended by Meeusen, replacing your styrofoam-cup cryotherapeutic device as often as needed.
Cryotherapy is not new: the famous Greek physician Hippocrates (460-370 BC) knew about the benefits of placing ice or snow on injured regions of the body. None the less, we are continuing to refine the manner in which ice is used therapeutically. Meeusen's research suggests that ice should be used often and for brief 10-minute intervals, rather than for more prolonged periods of time. It's a good recommendation. After all, overly long applications of ice can result in frostbite injury to the skin, nerve damage, and increased swelling and inflammation. The next time you injure yourself during your sporting activity (or even during every-day life), try Romain Meeusen's 10-minute ice applications, along with compression and elevation of the injured area, if possible. By using ice in this way, you won't chill your chances of a quick recovery.