Photobiomodulation (pbm) for circadian rhythm modulation and sleep improvement

A lighting arrangement for improving sleep in a human body having an unbalanced circadian rhythm by helping to normalize melatonin levels in the body, comprising:

• a radiation source configured to emit radiation with a peak wavelength in a range 760-1400 nm;
• an optical system arranged to direct the emitted radiation so that, during use, the body is irradiated in a predetermined treatment region;
• and
• a driver circuit operably coupled to the radiation source and the optical system and configured to provide a first driving current to the radiation source, wherein the driver circuit comprises program memory storing a dosing program which, when executed, causes the lighting arrangement to:
• (i) provide the first driving current to the radiation source
• (ii) accumulate a session energy density at the predetermined treatment region;
• and
• (iii) automatically suppress further emission upon reaching a target session energy density.