Lack of sleep : Consequences and symptoms to be aware of 💤

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Common causes of sleep deprivation

Environmental factors (noise, light, temperature)

Your sleeping environment is important, whether it’s:

- noise, even at low levels, can disrupt sleep cycles,

- light, with exposure to blue light from screens before bedtime delaying the production of melatonin,

- the temperature in a room that is too warm (above 19°C) is detrimental to falling asleep and deep sleep.

To optimise your sleep, create a calm, dark and cool environment.

Harmful lifestyle habits (screens, diet, irregular working hours)

As you will have noticed, certain everyday behaviours have a negative impact on sleep quality , such as:

- excessive use of screens in the evening, bearing in mind that 56% of French people use a screen just before going to sleep,

- an inappropriate diet, with hearty or spicy meals late at night disrupting digestion,

- irregular sleep schedules, such as going to bed and getting up at different times, which destabilises the biological clock.

Medical conditions affecting sleep

A variety of conditions can cause insomnia:

- sleep apnoea which affects 5-7% of the adult population,

- restless legs syndrome, which affects 8.5% of adults,

- depression and anxiety are often associated with sleep disorders.

If your sleep problems persist, consult a doctor to identify any underlying disorders.

Symptoms of sleep deprivation

Physical signs (fatigue, daytime sleepiness, headaches)

The physical manifestations of sleep deprivation are often the most obvious, such as:

- persistent fatigue on waking,

- excessive daytime sleepiness, with involuntary microsleeps,

- frequent headaches, particularly at the end of the day,

- stinging eyes or blurred vision.

A recent study shows that 56% of French people use a screen just before going to sleep, which can make these symptoms worse.

Cognitive impacts (problems with concentration, memory)

Lack of sleep also affects your cognitive abilities:

- reduced alertness and attention,

- difficulty concentrating, particularly on complex tasks,

- short- and medium-term memory problems,

- slower reaction times.

These effects can be particularly dangerous when driving or in certain high-risk professions.

Effects on mood and behaviour

Your behaviour and mood are also affected by lack of sleep, with:

- increased irritability and mood swings,

- a tendency to anxiety or depression,

- difficulty managing day-to-day stress,

- changes in appetite, with a tendency to overeat sweet or fatty foods.

A Finnish study showed that chronic insomnia in adulthood may increase the risk of cognitive decline in retirement.

The short-term consequences of sleep deprivation

Reduced alertness and the risk of accidents

⚠ According to the French road safety authority, the risk of an accident is multiplied by 3 to 4 at the first signs of drowsiness.

One study showed that that 24% of subjects who shortened their night's sleep (an average of 3 hours 53 minutes) had an accident, compared with 7 hours 17 minutes for a normal night's sleep.

Drowsiness at the wheel is the second leading cause of death on the motorway, accounting for 1 in 5 accidents.

Impaired cognitive performance

Tasks:

• complex,
• monotonous,
• long term.

These are the tasks that are particularly affected.

Sleep deprivation, even partial (4 hours per night over 7 days):

• reduces the speed of reaction,
• increases errors, particularly on the psychomotor vigilance test (PVT).

This results in reduced concentration, impaired memory and less effective decision-making.

Mood swings and irritability

One study has shown that people with irregular or inadequate sleep patterns show increased emotional instability.

This manifests itself as irritability, anxiety and, in some cases, depression.

Mood fluctuations are often exacerbated by accumulated fatigue and daily stress.

Long-term health consequences

Increased cardiovascular risks

Another study has shown that people suffering from sleep disorders have an increased risk of heart attack, stroke and coronary heart disease.

Lack of sleep:

• disrupts cell regeneration,
• increases blood pressure and bad cholesterol (LDL), which damages blood vessels.

The impact on metabolism and weight gain

Lack of sleep disrupts the hormones that control hunger and satiety, such as:

• ghrelin (the hunger hormone),
• leptin (satiety hormone).

This leads to an over-consumption of calories, often in the form of fatty and sugary foods, and a reduction in physical activity.

One study found that sleep-deprived people consume an average of 400 extra calories a day, which can lead to significant weight gain and increase the risk of obesity.

Weakening of the immune system

Lack of sleep disrupts the circadian rhythm of immune cells, reducing their effectiveness in fighting infections and viruses.

This results in a reduction in the number and quality of white blood cells and lymphocytes, increasing susceptibility to disease.

Effects on mental health (depression, anxiety)

Sleep deprivation is strongly linked to mental health problems, including depression and anxiety.

Studies show that people with irregular or inadequate sleep patterns have greater emotional instability and a higher risk of depression.

How can sleep deprivation be prevented?

Establish a regular sleep routine

Going to bed and getting up at regular times, even at weekends, helps to synchronise your biological clock.

This makes it easier to fall asleep and improves sleep quality.

Creating an environment conducive to sleep

Your bedroom should be a haven of peace where you can get a good night's sleep.

Here are a few tips:

- maintain a cool temperature (around 18-19°C),

- use blackout curtains to block out the light,

- limit noise sources with earplugs or a white noise machine,

- air the bedroom regularly for good oxygenation.

You can read our article on the sleeping environment.

Managing screen use before bedtime

The blue light emitted by screens (phones, tablets, computers) inhibits the production of melatonin, the sleep hormone.

It is advisable to avoid screens at least 1? hours before going to bed.

Instead, try relaxing activities such as reading or listening to soft music.

Sleep deprivation in specific populations

The effects of sleep deprivation in adolescents

Lack of sleep has consequences for teenagers such as:

- altered cerebral development, an Inserm study shows that chronic sleep deprivation reduces the volume of grey matter in several regions of the brain,

- reduced performance at school, difficulty concentrating, memorising and problem-solving,

- increased risk of depression and anxiety, with 30% of sleep-deprived teenagers showing depressive symptoms,

- risky behaviour, increased consumption of alcohol and drugs.

Sleep and productivity at work

Lack of sleep has an impact on professional performance:

- lower productivity,

- increase in errors,

- increased absenteeism,

- impaired decision-making.

Sleep deprivation and parenthood

Parents, especially of young children, are particularly affected by sleep deprivation:

- chronic fatigue: 76% of parents of children under 3 say they suffer from chronic fatigue,

- increased risk of post-partum depression: lack of sleep is an aggravating factor,

- tensions in the relationship: 30% of couples with young children report conflicts linked to lack of sleep,

- difficulty managing emotions: increased irritability and less patience with children.