Did you know that sleep loss can be accumulated? Lose a little sleep each night and, over time, you build a ‘sleep debt’ or ‘sleep deficit’.

The knock-on effect of regularly getting a bit less sleep than you need is that the deficit (or debt), increases. This can lead to mental or physical fatigue, and under-performance.

We sleep 20% less than we did before the lightbulb was invented. By coincidence, or not, industrialised nations are gradually becoming more and more sleep deprived.

Effects can be missed

The impact of too little sleep may seem obvious. After all, we all know when we are tired, don’t we? Well, no, not always. One of the sneaky effects of accumulated sleep-loss is that we stop recognising the signs. Sleep debt builds without us being aware of it.

What’s more, the long-term effects on our health are invisible until they become serious. These include increased risk of hypertension, diabetes, obesity, depression, heart attack, and stroke, for example.

Because tired people tend to under-perform and make mistakes, a sleep debt puts you at increased risk of errors of judgement and accidents.

Get your Zs – repay the debt

We have busy lives and whereas we are constantly barracked about diet and the need for exercise, not much is said about sleep. The exact mechanisms of how sleep works is not yet understood. What is known is that adequate sleep is necessary for healthy functioning, so a sleep debt puts us at risk. Furthermore, there is a reciprocal relationship between sleep, diet, and exercise. They are closely related and each one supports the other.

Any debt has a way of accumulating, and sleep is no different. The right amount of rest is, say the experts, seven to nine hours for a healthy adult. We can count minutes and hours in the same way that we can count calories. But while cutting calories can be good advice, we shouldn’t be tempted to cut cut sleep time in the same way.

See also

Harvard Medical School: Repaying your sleep debt