Effects of infrared radiation and exercise on bone mass: implications for the prevention and management of osteoporosis

Abstract

The aim of the current study was to investigate the effects of infrared radiation in conjunction with treadmill training on bone mass and muscle performance. Twenty postmenopausal women aged 50 to 60 years participated in this study. The investigated groups were (i) the Light Emitting Diodes (LED) group, which performed treadmill training associated with photobiomodulation therapy (n = 10) and (ii) the exercise group, which carried out treadmill training only (n = 10). Eighteen women completed the full study (9 per group). Training was performed for 12 months, twice a week for 45 min per session at 85 to 90% of maximal heart rate (HRmax); training intensity was determined by a progressive exercise testing. The irradiation parameters were infrared-LEDs (850 nm wavelength) at 100 mW power, 39 mW/cm2 power density, and 108 J/cm2 fluence for 45 min. Isokinetic dynamometry and bone densitometry were performed. The reduction in total femur bone mineral density (BMD) was significantly higher (p = 0.04) for the exercise group (∆ = − 0.024 ± 1.055 mg/cm3) compared with the LED group (∆ = − 0.011 ± 0.013 mg/cm3). The number of muscle contractions was significantly increased, while the fatigue was significantly reduced only in the LED group compared with baseline (p < 0.05). The average power was significantly higher for the LED and exercise groups compared with baseline (p < 0.01). There was no significant difference in quadriceps performance between 6 and 12 months for either group (p ≥ 0.05). Infrared radiation associated with treadmill training may synergistically act to further enhance muscle performance and attenuate the reduction of femur BMD, preventing osteoporosis and its associated health consequences.