Skip to content

How does a lack of sleep affect the body?

Everyone needs sleep, but its biological purpose remains a mystery. However, we know that quality sleep, and getting enough of it, is as essential to survival as food and water.1

We know that sleep habits and health are heavily linked, but how does a lack of sleep affect the body?

Sleep is important to a number of brain functions, it affects almost every type of tissue and system in the body – from the brain, heart, and lungs to metabolism, immune function, mood, and disease resistance.2,3

As you fall asleep, your body begins many important functions2,3:

  • Consolidating the learning and memories from the day
  • Healing damaged cells and removing metabolic waste
  • Recharging your immune system
  • Recovering from the day’s activities
  • Revitalise your heart and cardiovascular system for the next day

Sleeping more can help alleviate a number of health problems. The physical benefits of getting more sleep include increased memory, improved heart health, a strong immune system, decreased stress levels and easier weight management.4

How does a lack of sleep affect physical health?


Reduced heart health

Healthy sleep can have a positive impact on your heart health. Sleep affects processes that keep your heart and blood vessels healthy, including your blood sugar, blood pressure, and inflammation levels.2

Healthy sleep patterns also play a vital role in your body’s ability to heal and repair the blood vessels and heart. Getting limited duration of sleep or working shifts has been shown to increase risk of developing hypertension, cardiovascular disease, heart attack and stroke.3,5,6

Weight gain

Sleep deprivation can increase your risk of weight gain and obesity.5,6,7 Sleep-deprived people have reduced levels of leptin (the chemical that makes you feel full) and increased levels of ghrelin (the hunger-stimulating hormone) which is thought to contribute towards weight gain.7

Studies have shown that people who sleep less than 7 hours a day tend to gain more weight and have a higher risk of becoming obese than those who get 7 hours of slumber.7

Reduced immunity

Too little sleep can affect your ability to fight infections.6,7 Studies have shown when you are sleep deprived you are 3 times more likely to catch a cold.5

Good sleep will not only boost your immune system; sleep has been shown to be more important than nutrition in wound healing.8

Increased risk of type 2 diabetes

Poor sleep or too little sleep may increase your risk of developing type 2 diabetes, and the associated health problems.5,6,7 Studies show that people who usually sleep less than 5 hours a night have an increased risk of developing diabetes.5,7

It seems that missing out on deep sleep may lead to type 2 diabetes by changing the way the body processes glucose, which the body uses for energy.6,7

Increased risk of cancer

A lack of sleep has been linked to an increased risk in several types of cancer.6 Short sleep duration has been associated with a greater risk of developing breast cancer, colorectal cancer, and prostate cancer.6

Studies have reported a significantly increased risk of developing a number of cancers, including breast, colon, prostate, and endometrial cancer in night shift workers.6

Increased pain perception

A lack of sleep can increase your sensitivity and decrease your tolerance of pain, and consequently pain can affect your ability to sleep.10

Sleep deprivation has even shown to counteract the effect of some painkilling medicines demonstrating just how important pain is to our physical health.10

How does a lack of sleep affect mental health?


Impaired memory & learning

There is a wealth of evidence to show than sleep has a key role in memory retention & learning.11 Conditions like insomnia have been shown to impact cognitive functioning such as memory, attention, and concentration.13

Sleep quality and the amount of sleep students got have been closely linked in studies to student’s learning capacity and learning performance.12,13

There is also evidence to suggest that students across all education levels (school to university) are chronically sleep deprived – impacting their academic performance.12

Increased risk of dementia

Not only does a lack of sleep impact your memory and learning, it has also been to be linked to an increased risk for developing Dementia and Alzheimer’s in older adults.5,14 Maintaining good sleep may be beneficial in the prevention of Dementia and Alzheimer’s.14

Increased risk of mood disorders

The link between the effects of sleep deprivation, mood and mental wellbeing has been seen over and over by researchers and doctors.15 People with sleep disorders, such as insomnia, are 10 time more likely to have clinical depression and 17 times as likely to have clinical anxiety.15

It is a two-way street between sleep, mental illness and mood disorders – like anxiety and depression.13,15 Sleep can increase the risk of developing conditions like anxiety, depression, substance abuse and even psychosis. While anxiety, depression, substance abuse and psychosis can be detrimental to our quality of sleep.13,15 It’s a catch-22.

How does a lack of sleep affect our safety and quality of life?


Impaired work performance

There is clear evidence to suggest that sleep deprivation affects our attention, concentration and memory. This can impair our ability to work efficiently and safely.13 Conditions like insomnia have also been linked to absenteeism at work.13

Increased risk of accidents

A lack of sleep has been shown to result in significant impairments in cognitive and motor performance. This can increase the risk of motor vehicle crashes, work-related injuries and fatal accidents.6

Evidence shows that as much as 6000 fatal car crashes are caused by drowsy driving each year. And, that 1 in 25 drivers have fallen asleep at the wheel in the last month!5 Sleep deprivation has not only been linked to accidents on the road but in any work environment where there is the potential for human error.16

How can I reduce the impact of sleep deprivation?

If you have been missing out on getting enough sleep, there is only one way to compensate… getting more sleep.7

Depending on how much sleep you have been missing out on, it may take several weeks to recover from your sleep debt.7 You can build in extra hours of sleep on weekends or by going to you bed 1-2 hours earlier than you normally would to help compensate for the sleep loss over the long term.7

Try creating a comfortable sleeping environment

Make sure your mattress, pillows and covers are comfortable, and make sure your bedroom is dark and quiet – use thick curtains, blinds, an eye mask or ear plugs.17

Try relaxing your mind and body

Relax at least 1 hour before bed and try to go to bed at the same time every day, this helps program your mind for sleep.17 If you are going to exercise, do it during the day as strenuous physical activity too close to bedtime can impact sleep (no less than 4 hours before bed).17 Do not smoke, drink alcohol or caffeinated products at least 6 hours before going to bed.

Lloyds Pharmacy