There is growing evidence that inadequate sleep can contribute to a variety of health problems, including general well-being, slowing of cognition and increasing forgetfulness and memory loss. Incremental problems develop such as depression and anxiety, increased risk of cardiovascular disease, and even altered metabolism to increase the risk of obesity. It is usual for older individuals to seek an earlier bedtime and consequently an earlier waking time. Part of this is because your circadian rhythms have been altered, as your sleep is disrupted by repeated waking, so there is less time for the healing phases to operate.

Short-term underperformance for people who are sleep deprived is common and can be dangerous. One study described by Matthew Walker in his book was a careful assessment of driving skills using a driving simulator of healthy young individuals who were having eight hours of sleep per night. They were able to navigate faultlessly a complex course in the simulator. Their performance was compared with aged-matched individuals who were sleeping only four hours a night, being woken so they could achieve that time. The sleep-deprived cohort exhibited a six-fold increase in driving mistakes in the simulator.

One can speculate on a national and global scale what is the extent of the public health risk of drowsy and sleepy drivers.

Effects on the immune system

There is very strong evidence that subjects with inadequate sleep patterns have a less than optimal functioning immune system. Clinical studies evaluating people given nasal drops of a rhinovirus, a common cause of the common cold, showed they displayed symptoms of the infection in 50 per cent of cases where their sleep patterns were five hours or less. In contrast, an age-matched group who were sleeping around seven hours showed a far lower 18 per cent risk of the infection becoming clinical. This is a profound and accurate demonstration of the deleterious effect of poor sleep on the body’s immune system and susceptibility to infection. Responses to vaccination, such as for influenza or hepatitis B, are significantly reduced in the sleep-deprived patient.

From Ageing Well: How to Navigate Life’s Journey in Your Later Years by Dr Doug Wilson, published with permission of Calico Publishing.

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