The effects of heated humidification to nasopharynx on nasal resistance and breathing pattern.

BACKGROUND: Mouth breathing could induce not only dry throat and eventually upper respiratory tract infection, but also snoring and obstructive sleep apnea, while nasal breathing is protective against those problems. Thus, one may want to explore an approach to modify habitual mouth breathing as preferable to nasal breathing. The aim of this study was to investigate the physiological effects of our newly developed mask on facilitation of nasal breathing. METHODS: Thirty seven healthy male volunteers were enrolled in a double blind, randomized, placebo-controlled crossover trial. Participants wore a newly developed heated humidification mask or non-heated-humidification mask (placebo) for 10-min each. Subjective feelings including dry nose, dry throat, nasal obstruction, ease to breathe, relaxation, calmness, and good feeling were asked before and after wearing each mask. In addition, the effects of masks on nasal resistance, breathing pattern, and heart rate variability were assessed. RESULTS: Compared with the placebo mask, the heated humidification mask improved all components of subjective feelings except for ease to breathe; moreover, decreased nasal resistance and respiratory frequency accompanied a simultaneous increase in a surrogate maker for tidal volume. However, use of the heated humidification mask did not affect heart rate variability. CONCLUSION: Adding heated humidification to the nasopharynx could modulate breathing patterns with improvement of subjective experience and objective nasal resistance.

Effectiveness of thermotherapy using a heat and steam generating sheet for cartilage in knee osteoarthritis.

[Purpose] Superficial heat treatment is one of the most widely used physical therapies for osteoarthritis (OA). We clinically evaluated the effects of local heat treatment and exercise therapy for knee OA, and evaluated the articular cartilage using magnetic resonance imaging (MRI) T2 mapping. [Subjects and Methods] Eighteen females aged 50-69 (59.5 ± 8.5 years, mean ± SD) years diagnosed with early-stage knee OA were randomly assigned using computer-generated random numbers to either a local heat treatment group (LH group, 9 subjects) or an exercise therapy group (EX group, 9 subjects). These groups were subjected to a 12-week intervention experiment. MRI T2 mapping was performed for cartilage imaging and quantitative evaluation. For clinical evaluation, the Japanese Knee Osteoarthritis Measure (JKOM) and the Timed Up and Go (TUG) test were performed. Both clinical and MRI evaluations were performed at the beginning and end of the intervention (0 week (Time 0) and 12 weeks). [Results] The total JKOM score had a significantly decreased in the LH group at 12 weeks. However, in the EX group the total JKOM scores at Time 0 and 12 weeks were not significantly different. The TUG time in the EX group was significant shorter at 12 weeks, whereas it showed no significant change in the LH group at 12 weeks, though the TUG times of 7 of the 9 patients decreased, exhibiting some improvement. The T2 value of the LH group was significantly shorter at 12 weeks. However, the T2 value in the EX group showed no significant change at 12 weeks. [Conclusion] After local heat treatment using heat- and steam moisture-generating sheets for 12 weeks, we observed improvements in clinical symptoms and walking abilities. Moreover, positive effects on cartilage metabolism were suggested.

Responses of muscle mass, strength and gene transcripts to long-term heat stress in healthy human subjects.

The present study was performed to investigate the effects of long-term heat stress on mass, strength and gene expression profile of human skeletal muscles without exercise training. Eight healthy men were subjected to 10-week application of heat stress, which was performed for the quadriceps muscles for 8 h/day and 4 days/week by using a heat- and steam-generating sheet. Maximum isometric force during knee extension of the heated leg significantly increased after heat stress (~5.8%, P < 0.05). Mean cross-sectional areas (CSAs) of vastus lateralis (VL, ~2.7%) and rectus femoris (~6.1%) muscles, as well as fiber CSA (8.3%) in VL, in the heated leg were also significantly increased (P < 0.05). Statistical analysis of microarrays (SAM) revealed that 10 weeks of heat stress increased the transcript level of 925 genes and decreased that of 1,300 genes, and gene function clustering analysis (Database for Annotation, Visualization and Integrated Discovery: DAVID) showed that these regulated transcripts stemmed from diverse functional categories. Transcript level of ubiquinol-cytochrome c reductase binding protein (UQCRB) was significantly increased by 10 weeks of heat stress (~3.0 folds). UQCRB is classified as one of the oxidative phosphorylation-associated genes, suggesting that heat stress can stimulate ATP synthesis. These results suggested that long-term application of heat stress could be effective in increasing the muscle strength associated with hypertrophy without exercise training.

Application of heat- and steam-generating sheets to the lumbar or abdominal region affects autonomic nerve activity.

Effects of applying a heat- and steam-generating (HSG) sheet on peripheral hemodynamics and autonomic nerve activity were examined. An HSG sheet was applied to the lumbar or abdominal region. Measurements included skin temperature at the lumbar and abdominal regions and the fingertip, total hemoglobin, tissue oxygen saturation ratio (StO2), pupillary light reflex, changes in ECG R-R interval blood pressure and percutaneous electrogastrography (EGG). A heat-generating sheet without steam was used as the control. Based on the present findings, application of the HSG sheet to the lumbar or abdominal region may improve peripheral hemodynamics and inhibit sympathetic nerve activity, resulting in parasympathetic nerve activity dominance.