Heating Pads / Warm Compresses

A pooled analysis of randomized trials in people with osteoarthritis found improved grip strength (SMD = 0.43, p = 0.01; effect SMD 0.43 [0.1, 0.76]).

A 2021 pooled analysis combining randomized and non-randomized human studies found an average systolic blood pressure decrease of 3.94 mmHg in research that included people with peripheral artery disease.

In a 2025 trial of 34 people, peak blood flow during PLM increased by ~8.5% in the thermotherapy group, similar to the ~10.5% increase in the exercise group. A 2024 trial found regional venous blood flow increased during thermotherapy, while regional arterial flow remained unchanged.

A 2019 trial found that six-minute walking distance increased by 41 m from about 350 m (95% CI: [13, 69], P = 0.006), regardless of group. Another trial found no between-group difference in its reported outcome (P = 0.21), so results do not consistently show an endurance benefit.

In a 2020 trial of 35 people, the intervention group showed improvement over time in upper-trapezius muscle tone and stiffness.

A 2023 cohort study of 50 people reported greater declines in IP-10 and MIG one month after treatment compared with the warm compress group. By contrast, a 2026 pilot study of 10 people found no change in fasting plasma IL-6, TNF-α, CRP or IL-1ra, so findings differ across studies.

In a 2022 trial, fatigue scores after warm compression were 59.6 ± 4.4 versus 63.1 ± 5.6 in the control group (n = 120, p < 0.001). This finding concerns fatigue scores, rather than a direct measure of physical energy.

Among mothers with premature newborns in the NICU, mean breast milk amounts were 1,470 ± 718.93 mL in the warm compression group and 913.75 ± 679.90 mL in the control group (n=120). The massage-warm group mean was 1,484.23 ± 889.28 mL.

Trials found improvements in knee symptoms and some pain and quality-of-life measures among people with osteoarthritis or rheumatoid arthritis. However, a 2026 pooled analysis of randomized trials found no significant difference in AUSCAN scores between heat therapy and control, so results differ by measure and study.

In a 2020 trial of 35 people, cervical and shoulder alignment improved over time. Adding a salt pack to neck stabilization exercises was not significantly more effective than the exercises alone.

A 2023 pilot study in people with chronic kidney disease found a 38.6% decrease in subjective anxiety immediately after treatment (n = 22, p = 0.0139). Another trial involving breastfeeding mothers reported decreased maternal anxiety, so findings across these settings differ.

Expert knowledge suggests that post-exercise heat may increase blood flow and help clear metabolic waste, which could support muscle recovery. This effect was mentioned in 3 of 128 Reddit reports discussing it; those reports are people’s accounts, not evidence of an effect.

Expert knowledge describes heat therapy as improving tissue extensibility and joint range of motion, but human evidence is not listed.

The proposed rationale is that chest warming may help loosen secretions and reduce bronchospasm in mild respiratory conditions.

A pooled analysis of randomized trials found that other thermal therapies were not statistically significant for muscle soreness (P > 0.05); studies did not support this effect.

A 2023 pilot study found no significant changes in positive or negative mood characteristics (n = 22); studies did not support a mood-improving effect.

A pooled analysis of randomized and non-randomized human studies found resting heart rate was unchanged (n = 10; MD: -1.25 beats/min; 95% CI: -3.20, 0.70; P = 0.21); studies did not support an improvement.

A 2024 trial found no significant differences among groups in SpO2 or pulse rates (n = 59; SpO2 F = 0.02, p = .981; pulse F = 0.78, p = .462); studies did not support an improvement.

A 2026 pilot study found no difference in glucose tolerance between control and intervention (n = 10; glucose area under the curve Control: 7410 ± 6088 mg/dl*180min, Intervention: 8253 ± 2139 mg/dl*180min; P = 0.857); studies did not support this effect.

A 2025 pilot study in people with fibromyalgia found no statistically significant changes in depression, anxiety, quantitative sensory testing measures, or pro- or anti-inflammatory markers (n = 13); studies did not support an antidepressant effect.

An 2026 trial of 84 people found that heat applied to the lumbar region did not demonstrate a benefit over standard care; studies did not support constipation relief.

A randomized trial involving 59 people with nonspecific back pain found that heat therapy reduced pain by more than the minimum clinically important difference. Another trial found reduced pain and disability when thermotherapy was combined with general stretching exercises in people whose nonspecific low back pain had lasted under 3 months.

A randomized trial involving 88 women with primary dysmenorrhea found that thermotherapy reduced pain intensity compared with placebo.

A pilot study reported reduced pain and fibromyalgia impact after 4 weeks of hot-water immersion in women with fibromyalgia.

One small randomized trial found that adding salt-pack thermotherapy to exercise improved pain, pressure pain threshold, and disability in 35 elderly women with chronic nonspecific neck pain.

A pilot involving 22 people found an immediate reduction in self-reported anxiety, but baseline anxiety was low; the authors recommended testing in groups with higher anxiety.

A randomized trial involving 30 people with frozen shoulder reported improvement in the Shoulder Pain and Disability Index when thermotherapy was combined with Kaltenborn mobilization, so the finding does not isolate the effect of heat alone.

A randomized placebo-controlled trial involving 66 patients with acute coronary syndrome reported reduced chest pain after local heat at 50 °C.

A 2019 randomized trial in 18 obese women with PCOS found metabolic and androgen improvements; these results have not been tested in people without PCOS.

A randomized trial involving 28 people with diagnosed, bothersome restless legs syndrome found that heat therapy improved sleep-problem scores compared with no intervention, but did not significantly change restless legs syndrome severity or quality of life.

A review of 7 small, poor-quality trials suggested that superficial moist heat may provide palliative therapy for rheumatoid arthritis.

Warm eyelid compresses are a standard part of lid hygiene for blepharitis, especially when meibomian gland dysfunction is present.

Pooled analyses of randomized trials reported itching from a fingerless glove used in heat therapy and skin rash. The findings came from studies involving people with chronic kidney disease, chronic pain, or osteoarthritis.

In a randomized trial involving 161 people, best-corrected visual acuity loss of 10 or more letters was judged related to treatment and resolved in 1 week. Another randomized trial involving 144 people reported ocular events possibly related to warm compresses, including blurred vision, dryness, and eyelid edema.

A 2022 randomized trial with 33 participants reported irritability.

A 2024 review pooling randomized and non-randomized human studies reported lymph node swelling.

A 2019 pilot with 12 participants reported severe allergic conjunctivitis.

A pilot study involving 10 people reported mild constipation.

Prolonged or excessively hot application can cause thermal skin burns, particularly during sleep or when sensation is impaired.

A six-month RCT found no improvement in balance in either the whole-body vibration group or the group combining whole-body vibration with heat therapy.

In a 22-person pilot, self-reported anxiety remained 19.3% lower at the one-week follow-up, but the reduction was not statistically significant compared with baseline (p = 0.1397).