Poor sleep over the long term is associated with a number of negative health outcomes, including high blood pressure, diabetes, obesity, depression and lower sex drive. A recent study now indicates that it may increase the risk of osteoporosis as well.
The study found that women who usually sleep for five hours per night or less had significantly lower bone density than those who slept for seven hours. The researchers suggested that lack of sleep could, therefore, negatively impact bone health, adding to the many other health problems that poor sleep can cause.
Bone density is the amount of bone mineral in bone tissue. A lower bone density means that the bones are more fragile and prone to fracture. Women and older people are more likely to have low bone density. Other risk factors include poor diet, having a sedentary lifestyle and genetic predisposition.
The new study, published in early November in the Journal of Bone and Mineral Research, tested over 11,000 women who were all post-menopausal (the period in life when bone health most suffers). The women were asked to complete sleep questionnaires and then underwent hip, spine and whole body DX scans to measure their bone mass.
The women who slept for seven hours a night had better bone density in their hips, spines and whole bodies when compared with women who slept for five hours or less. These women were therefore at a lower risk of osteoporosis, a health condition that weakens the bones and leaves sufferers more likely to experience fractures. The researchers did not find that sleeping for more than seven hours had any impact.
The difference in bone health between the two groups of women was found to be significant. The researchers described it as equivalent to one year of ageing and suggested that this could be due to a process called ‘bone remodelling’. This process lasts throughout life and involves older bone tissue being removed from the skeleton via reabsorption and new bone tissue being formed. Like many of the body’s renewal processes, bone remodelling usually takes place while the body is asleep. The researchers have suggested that, for those women in the study who slept too little, bone remodelling was not taking place properly, and this could explain why these participants had poorer bone density.
The study only focused on post-menopausal women in the USA, and therefore more research is required to confirm whether the relationship between bone health and sleep applies to the wider population. Further, while the study shows that there is a link between poor sleep and low bone mineral density, additional research will be needed to confirm whether bone problems are actually caused by lack of sleep. The findings do, however, indicate that sleep may well have an impact on bone health, as it does on many other aspects of our physical and mental wellbeing.