Table 2.

Evidence for the effectiveness of heat wrap therapy in the treatment of low back pain.

Author (Year)	N	Study Design	Study Treatment	Comparator(s)	Primary Endpoint Results	Other Endpoints/Outcomes
Acute low back pain
Nadler 2002 [46]	371	Prospective, randomized, single-blind, comparative, multicenter study Two days of treatment Two days of post-treatment follow-up	Continuous low-level heat wrap: 8 h/day at 40 °C for two days (n = 113)	Ibuprofen, 1200 mg/day (n = 106) Acetaminophen, 4000 mg/day (n = 113) Oral placebo (n = 20) Unheated back wrap (n = 19)	Pain relief on Day 1: Significantly greater with a heat wrap vs. acetaminophen (p = 0.0001) or ibuprofen (p = 0.0007)	Compared to acetaminophen or ibuprofen, a heat wrap wassignificantly associated with: (a) greater pain relief on Day 2 and extended pain relief (Days 3 and 4) (b) reduced muscle stiffness (Days 1–4) (c) improved flexibility (Days 2 and 4) (d) reduced disability (Days 2 and 4)
Nadler 2003 [47]	219	Prospective, randomized, parallel, single-blind, placebo-controlled, multicenter study Three days of treatment Two days of post-treatment follow-up	Continuous low-level heat wrap: 8 h/day at 40 °C for three consecutive days (n = 95)	Oral placebo (n = 96) Oral ibuprofen (n = 12) Unheated back wrap (n = 16)	Pain relief on Day 1: Significantly greater with a heat wrap vs. placebo (p < 0.001)	Compared to the placebo, a heat wrap was significantly associated with: (a) greater pain relief on Days 2 and 3 andextended pain relief (Days 4 and 5) (b) reduced muscle stiffness (Days 1–5) (c) improved flexibility (Days 1–5) (d) reduced disability (Days 3 and 5)
Nadler 2003 [48]	76	Prospective, randomized, parallel, single-blind, placebo-controlled, multicenter study Three nights of treatment Two days of post-treatment follow-up	Continuous low-level heat wrap: 8 h/night at 40 °C for three consecutive nights (n = 33)	Oral placebo (n = 34) Ibuprofen (n = 4) Unheated heat wrap (n = 5)	Morning pain relief on Days 2–4: Significantly greater with a heat wrap vs. placebo(p = 0.00005)	Compared to the placebo, a heat wrap was significantlyassociated with: (a) greater pain relief the following day and extended pain relief (Days 2–5) (b) reduced morning muscle stiffness in the morning and during the day (Days 2–5) (c) reduced disability at the end of treatment and follow-up (d) improved trunk flexibility on Day 4 (e) improved sleep quality and onset of sleep
Lurie-Luke 2003 [49]	52	Workplace intervention study Two days of treatment Two-week post-treatment follow-up	Continuous low-level heat wrap: 8 h/day at 40 °C for two consecutive days	–	A heat wrap significantly reduced pain intensity and impact of pain on work-related activities and sleep for two weeks post-treatment	A heat wrap was associated with a reduction in the use of other over-the-counter pain relief products A heat wrap was rated as “excellent” or “very good” by 44% of respondents and as “good” by 37%
Tao 2005 [50]	43	Randomized workplace study Three days of treatment 11 days of post-treatment follow-up	Continuous low-level heat wrap: 8 h/day at 40 °C for three consecutive days plus back pain education (n = 25)	Back pain education alone(n = 18)	Pain intensity and pain relief during treatment and follow-up: Heat wrap + education significantly reduced pain intensity (Days 1–14) and provided improved pain relief (Days 1–4) vs. education alone	Compared to education alone, heat wrap + education wasassociated with: reduced disability on Days 7 and 14
Mayer 2005 [51]	100	Randomized, controlled outpatient study Five days of treatment Two days of post-treatment follow-up	Continuous low-level heat wrap: 8 h/day at 40 °C plus exercise for five consecutive days n = 24)	Heat wrap alone (n = 25) Exercise alone (n = 25) Educational booklet (control; n = 26)	Functional ability: Heat wrap + exercise significantly improved functional outcomes vs. exercise alone (p = 0.18), or the control (p = 0.002) on Day 4 and vs. a heat wrap alone (p = 0.0007), exercise alone (p = 0.0003) or the control (p < 0.0001) at Day 7	Compared to a heat wrap alone, exercise alone, or the control, a heat wrap + exercise was significantly associated with: (a) less deficit from pre-injury function on Day 7 (b) reduced disability on Day 7 (and on Day 4 vs. the control) (c) greater pain relief on Days 4 (vs. the control) and 7 (vs. exercise alone and the control)
Kettenmann 2007 [54]	30	Randomized, active-controlled, parallel design study Four days of treatment One day of post-treatment follow-up	Continuous low-level heat wrap: ≥4 h/day at 40 °C for four consecutive days plus oral analgesics (as needed; n = 15)	Oral analgesics (as needed; n = 15)	Objective evidence of reduced pain arousal (EEG data): A heat wrap led to significantly greater drops in Beta-1 and -2 frequencies post-treatment vs. the control (Days 2 and 4)	Subjective evidence Compared to the control, a heat wrap was significantlyassociated with: (a) reduced pain (Days 2–4) (b) reduced stress (Day 3) (c) reduced tiredness (Days 2 and 4) (d) improved sleep quality (Day 4) (c) improved concentration (Days 2, 4) A heat wrap was rated as “excellent,” “very good,” or “good” by 86% of respondents
Stark 2014 [55]	61	Pilot study to evaluate sensitivity of two methods to assess time to onset of pain relief and flexibility	Continuous low-level heat wrap: 8 h at 40 °C (n = 26)	Oral placebo (n = 25) Sham wrap (n = 5) Oral ibuprofen (n = 5)	Median time to first pain and meaningful relief were both significantly shorter for heat wrap vs. placebo (p = 0.046 for both)	Compared to the placebo, a heat wrap was significantlyassociated with: (a) greater pain relief (b) greater change in muscle stiffness
Petrofsky 2015 [57]	145	Randomized, controlled outpatient study	Continuous low-level heat wrap: 6 h at 40 °C prior to home exercise program over two weeks (n = 71)	Home exercise program over two weeks without prior heat therapy (n = 7)	Compared to the control, a heat wrap was associated with a significantly greater: (a) improvement in strength after the two-week period (p < 0.01) (b) improvement in flexibility after the two-week period (p < 0.01) (c) reduction in disability after the two-week period (p < 0.01) (d) reduction in pain after the two-week period (p < 0.01) (e) compliance in the completion of home exercise (p < 0.01) Similar results were observed in patients with knee (n = 44) and neck (n = 59) pain
Chronic low back pain
Lewis 2012 [52]	24	Prospective single-arm study (within-subjects repeated measures design)	Continuous low-level heat wrap: 40 °C applied 2 h prior to assessment	Assessment without prior heat wrap application	Pain ratings were impacted by the fluctuating nature of chronic LBP Heat wrap treatment was associated with a reduction in non-normalized muscle activity and improved short-term well-being
Freiwald 2018 [29]	176	Randomized, active controlled, multicenter, single-blind, observational study 12 weeks treatment	Continuous low-level heat wrap: 8 h at 40 °C plus multimodal treatment for 12 weeks (n = 88)	Multimodal treatment only (n = 88)	Muscular strength and flexibility: (a) strength and flexibility improved in both groups (b) significantly greater improvements in extension, and right and left rotation observed in the heat therapy-supplemented group