A new Danish research project led by Chief Physician and Ph.D. Anders Sode West suggests that Chromaviso’s circadian lighting may play an important role in protecting brain-injured and other hospitalized patients from losing bone mass.
When patients are admitted after a stroke, they face an increased risk of losing bone mass and, over time, developing osteoporosis. This is primarily due to prolonged immobility and reduced mechanical load on the bones. However, disruptions to circadian rhythms and hormonal balance may also contribute.
In a clinical study conducted at Rigshospitalet Glostrup, researchers investigated whether circadian lighting—designed to align with the body’s biological clock—could help support hormonal balance and thereby reduce the risk of bone loss.
Chromaviso’s circadian lighting is designed to mimic the natural changes in light over the course of a day, thereby supporting the body’s internal rhythm. In the morning, a warm, amber light turns on—similar to a sunrise. Throughout the day and afternoon, the light intensity and color temperature gradually increase into a bright, bluish light—resembling daylight when the sun is high in the sky. In the evening, the lighting dims again into warm tones like a sunset. At night, the light is dim and orange—completely free from blue light, which can otherwise disrupt sleep.
The study was conducted in a specialized stroke unit with patients undergoing rehabilitation after stroke. A total of 90 patients were randomized to either a unit equipped with Chromaviso’s circadian lighting or a unit with standard hospital lighting.
To assess the effect of the light, the researchers collected blood samples six times per day, both at admission and at discharge.
In this part of the study, 45 patients had their blood values measured around the clock:
- 25 in Chromaviso’s circadian lighting
- 20 in standard hospital lighting
The focus was on the circadian rhythm of calcium metabolism, including PTH (parathyroid hormone), which plays a central role in the body’s regulation of bone mass.
What did the study show?
Results: Circadian lighting lowered PTH
The most important finding was that the level of the hormone PTH (parathyroid hormone) decreased significantly in the group exposed to circadian lighting – but not in the control group exposed to standard hospital lighting.
PTH regulates the body’s calcium balance and plays a key role in bone metabolism. High levels of PTH are associated with bone loss and an increased risk of fractures – especially in immobile patients.
A reduction in PTH may therefore help protect against the bone loss that typically occurs during prolonged inactivity.
What does it mean?
The study shows that Chromaviso’s circadian lighting may have a health-promoting effect—not only on sleep and well-being, but also on the body’s hormonal balance and bone health during illness. Light is not just something we see—it is a biological signal that controls a wide range of important processes in the body. And with the right light at the right time, it’s possible to support the body’s natural circadian rhythms—even during a hospital stay.