In studies, short sleep duration has been linked to the risk of obesity, overall mortality rate, and risk of depression among pregnant women. Secretion of growth hormone, critical for healing and growth, has also been linked to sleep quality and quantity.
Other studies suggest that sleep quality improves when sleeping on or under wool. This appears to be related to wool's unique temperature and moisture management properties, and texture.Studies across the years have also indicated the incidence of allergies to wool is rare. In a controlled study reported in the Medical Journal of Australia, it was observed that use of a fleecy wool underlay significantly reduced observed postural activity (so sleepers were more “settled”) and improved the sleeper's own assessment of sleep quality.
Another study revealed that sleepers preferred wool blankets (when compared with cotton/acrylic blends) for their thermophysiological comfort properties, which were shown to be substantially different.
In studies conducted in Australia and South Africa, wool sheepskin underlay was shown to be better at diffusing pressure points when compared with cotton sheets. And in another study, affected patients needed to be turned or rolled less often on the sheepskin underlay, and developed fewer pressure ulcers.
Other research revealed sufferers of fibromyalgia (diffuse chronic pain and presence of tender points) showed significant lessening of pain, and significantly improved assessments of sleep quality when using wool underlays.
In three Dutch and Australian trials conducted in hospitals and nursing homes, use of wool-on sheepskin as underlay more than halved the incidence of sacral pressure ulcers.
One trial showed the rate of weight gain in underweight newborns was 61 per cent higher when sleeping on a wool underlay compared to a cotton sheet. A larger follow-on trial confirmed the much higher weight gain.
Research conducted on jaundiced newborns revealed that those sleeping on wool were more settled when sleeping compared to those on cotton - spending 8 per cent more time without minor movements, 14 per cent less time performing major movements, and crying less (about 30 per cent of babies on wool cried compared with 67 per cent on cotton).