Extended swimming exercise reduces inflammatory and peripheral neuropathic pain in rodents.
Physical exercise is often recommended to patients who have chronic pain. However, only a small number of studies report exercise-induced analgesia in the setting of inflammatory pain, and even fewer relate long-term exercise to reductions in neuropathic pain. To address these questions, we evaluated the effect of extended swimming exercise in animal models of inflammatory (intraplantar injection of dilute formalin) and neuropathic (partial peripheral nerve injury) pain. We found that 9 days of swimming exercise in 37 degrees C water for 90 min/d decreased licking and flinching responses to formalin, as compared with nonexercised control animals. In addition, 18 to 25 days of swimming decreased nerve injury-induced cold allodynia and thermal hyperalgesia in rats, and 7 days of swimming decreased nerve injury-induced thermal hyperalgesia in mice. Our data indicate that swimming exercise reduces behavioral hypersensitivity in formalin- and nerve injury-induced animal models of persistent pain.


CONCLUSIONS
Surprisingly, few animal studies have investigated the effects of extended exercise on chronic pain. Our results support the use of exercise as a nonpharmacological approach for the management of peripheral neuropathic pain.
Kuphal
Karen E
KE
Department of Physical Therapy and Rehabilitation Science, Kansas University Medical Center, Kansas City, Kansas, USA.
Fibuch
Eugene E
EE
Taylor
Bradley K
BK
D000704:Analysis of Variance; D000818:Animals; D003080:Cold Temperature; D004195:Disease Models, Animal; D005557:Formaldehyde; D006930:Hyperalgesia / Q000628:therapy; D007249:Inflammation / Q000139:chemically induced / Q000150:complications*; D008297:Male; D051379:Mice; D010146:Pain / Q000209:etiology*; D059408:Pain Management; D017288:Pain Threshold; D010805:Physical Conditioning, Animal / Q000379:methods*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time; D012585:Sciatica / Q000150:complications*; D013550:Swimming; D013997:Time Factors
D005557:Formaldehyde