#12. SPECIFIC FREQUENCIES & FREQUENCY
-BASED RESEARCH
The Effects of Specific Frequencies on Human Health & Function
INTRODUCTION
Research has examined whether changing the specific frequency of externally delivered sound can produce different responses in the human body and brain. Clinical and experimental studies have investigated frequency-specific effects on pain, comfort, sleep, stress, cardiovascular responses, auditory processing and neurological function.
SCIENTIFIC RESEARCH & PUBLISHED STUDIES
Effects of Sound Frequencies on Pain and Comfort During Intramuscular Injection: A Randomized Controlled Study
A randomized controlled study of 300 patients examined sound stimulation at frequencies from 10 to 200 Hz during intramuscular injection. Pain decreased as frequency increased, with the strongest reductions and improvements in comfort at 150 and 200 Hz; higher frequencies also reduced injection-related heart-rate and blood-pressure responses.
Acute Music-Frequency Exposure Modulates Salivary Stress and Neurotrophic Markers in Young Adults: A Randomized Controlled Trial
A randomized controlled trial of 162 healthy university students compared 20 minutes of music at 528 Hz, 432 Hz, or no music. The 528-Hz group showed significantly increased salivary BDNF and CREB compared with control, while the 432-Hz group showed increased GRP78; no significant differences were found in Stroop cognitive performance.
Music tuned to 432 Hz versus music tuned to 440 Hz for improving sleep in patients with spinal cord injuries: a double-blind cross-over pilot study
A double-blind cross-over pilot study of 12 patients with spinal cord injuries compared music tuned to 432 Hz and 440 Hz. Sleep scores improved significantly after the 432-Hz intervention (+3.6, p=0.02), while no significant improvement occurred with 440 Hz; perceived stress decreased with both frequencies but not significantly.
Effect of music at 432 Hz and 440 Hz on dental anxiety and salivary cortisol levels in patients undergoing tooth extraction: a randomized clinical trial
A randomized clinical trial of 42 patients undergoing tooth extraction compared music at 432 Hz, 440 Hz, or no music. Both music groups had significantly lower anxiety than the control group, while the 432-Hz group had significantly lower salivary cortisol than both the 440-Hz group and control group.
Music Tuned to 440 Hz Versus 432 Hz and the Health Effects: A Double-blind Cross-over Pilot Study
A double-blind cross-over pilot study of 33 healthy adults compared 20 minutes of the same music tuned to 432 Hz and 440 Hz. Music tuned to 432 Hz was associated with a mean heart-rate decrease of 4.79 beats per minute (p=0.05), while blood-pressure and respiratory-rate changes were not statistically significant; participants also reported greater focus and satisfaction with 432-Hz music.
Tinnitus suppression with threshold and subthreshold sound stimuli
A preliminary study of 34 patients with tinnitus examined frequency-specific sound stimuli. Complete tinnitus suppression occurred in 22 participants (64.7%), partial suppression in 5 (14.7%), and no response in 7 (20.6%), providing preliminary evidence that frequency-specific sound stimulation can alter tinnitus perception in some individuals.
Differential effects of sound interventions tuned to 432 Hz or 443 Hz on cardiovascular parameters in cancer patients: a randomized cross-over trial
A randomized cross-over trial of 43 cancer patients compared 15-minute sound interventions tuned to 432 Hz and 443 Hz using a body monochord. Both interventions reduced heart rate, but the reduction was greater with 432 Hz; 432 Hz also significantly increased heart-rate variability and reduced pulse-wave velocity, while both frequencies produced improvements in emotional well-being and reductions in fatigue, anxiety and stress.