Heat Pad vs TENS Unit for Neck Pain
For neck pain, use a heat pad rather than a TENS unit—heat therapy has proven moderate efficacy for short-term pain relief, while TENS has failed to demonstrate effectiveness beyond placebo in high-quality trials. 1
Evidence Supporting Heat Therapy
Heat therapy provides meaningful short-term pain relief for musculoskeletal neck and back pain through several mechanisms:
Heat wrap therapy or heated blankets demonstrate moderate superiority over placebo for short-term pain relief and functional improvement in multiple higher-quality trials, with consistent evidence from Cochrane systematic reviews 1
Heat application increases blood flow to tissues, reduces muscle spasm, and provides analgesic effects that translate to clinically meaningful pain reduction 2
When combined with physical therapy, continuous low-level heat significantly improved pain scores, range of motion, and home exercise compliance in patients with chronic nonspecific neck pain compared to placebo (p<0.01) 2
Heat therapy is superior to oral acetaminophen or ibuprofen alone for short-term pain relief (3-4 days), with differences of 0.66 and 0.93 points on a 6-point pain scale 1
Adverse events are minimal, consisting mainly of minor skin irritation that rarely requires discontinuation 1
Evidence Against TENS Units
TENS units have consistently failed to demonstrate efficacy for neck or back pain:
A large, higher-quality trial found no differences between TENS and sham TENS for any measured outcome in chronic low back pain 1
A Cochrane systematic review concluded that while one lower-quality trial suggested benefit, the larger and more rigorous studies showed TENS was no better than placebo 1
TENS showed no difference from acupuncture in 4 trials, and evidence for acute or subacute pain is insufficient from lower-quality studies only 1
Multiple systematic reviews examining therapeutic modalities for neck pain found that electrical therapies including TENS have little evidence of effectiveness and no evidence for more than transient benefit 3
Practical Application Algorithm
For acute neck pain (< 6 weeks):
- Apply heating pad for 30 minutes, 2-3 times daily 1, 2
- Combine with NSAIDs (ibuprofen 400mg) for additive effect 2, 4
- Continue heat therapy for 3-7 days during acute phase 1
For chronic neck pain (> 12 weeks):
- Use continuous low-level heat as adjunct to physical therapy between sessions 2
- Heat application improves compliance with home exercise programs (p<0.05) 2
- Expect modest pain reduction but improved functional outcomes when combined with active treatment 2
Critical Caveats
Do not rely on heat or TENS as monotherapy—both are adjunctive treatments only. The strongest evidence for neck pain management supports exercise therapy, with weaker evidence for massage, acupuncture, and spinal manipulation 5
Screen for red flags before recommending self-care: Constitutional symptoms, progressive neurological deficits, history of malignancy, or intractable pain require immediate MRI evaluation rather than conservative management 6, 7
Heat provides only short-term benefit—effects typically last 3-4 days and are not sustained beyond one week without continued application 1
Patient preference matters for adherence: While heat is more effective than TENS based on evidence, both modalities showed similar patient satisfaction rates (80.6% vs 75.9% would use again), suggesting that if a patient strongly prefers one modality, compliance may be enhanced 4