Sleep specialists encourage getting at least seven hours of sleep each night. Medics explain that a single night of poor sleep can leave one feeling lazy and too tired to work efficiently, exercise, or eat healthfully. And over time, continued sleep deprivation raises the risk of a number of chronic health problems, including obesity, diabetes, high blood pressure, and heart disease. Insufficient sleep can also leave a person more vulnerable to mental health issues such as depression and anxiety.

Lack of sleep can reduce memory and learning ability. Researchers have found that just five hours of lost sleep in a 24-hour period can cut off the connection between neurons in the hippocampus, the area of the brain associated with memory.

The World Health Organization (WHO) research on cardiovascular disease, explains that poor sleep and sleep disorders interfere with heart health, increasing one’s risk of heart attack and stroke.

"During the last few decades, many studies have reported a strong association between sleep duration and mortality risk. These findings have shown that individuals sleeping between seven to nine hours at night, experience the lowest risks for all-cause mortality when compared to those who sleep for shorter or longer periods,” states Sleep Science, an official journal of the Brazilian Sleep Society.

Sleep Science also adds that even though the lack of sleep is thought of as an individual or a personal issue, insufficient sleep can have much wider adverse social and economic effects. Due to its potential negative impact on higher functions, such as judgment, decision-making, and reaction time, sleep deprivation can increase the risk of fatal accidents and injury.

According to Harvard Health Publishing, in rare cases, insufficient sleep can even be more dangerous. A sleep shortfall can lead to daytime drowsiness and "micro sleeps.” Micro sleeps are brief bouts of sleep that occur during the day that usually last just a few seconds.

If you have ever briefly nodded off while sitting through a lecture or work, you have experienced micro sleep. They usually last just a few seconds but can go on for 10 or 15 seconds—and pose a serious danger if they happen while someone is driving as it can lead to motor accidents.

The Centers for Disease Control and Prevention (CDC), explains that children and adolescents who do not get enough sleep have a higher risk of many health problems, including obesity, type 2 diabetes, poor mental health, and injuries. They are also more likely to have attention and behaviour problems, which can contribute to poor academic performance in school.

CDC urges students to have the proper amount of sleep at night to help stay focused, improve concentration, and academic performance.

"Getting enough sleep is important, but good sleep quality is also essential. Signs of poor sleep quality include feeling sleepy or tired even after getting enough sleep, repeatedly waking up during the night, and having symptoms of a sleep disorder (such as snoring or gasping for air). Better sleep habits may improve the quality of your sleep,” states CDC.

Causes of insufficient sleep

In 2006, the Institute of Medicine report emphasised insufficient sleep is more common in individuals who do the night shift work or who work more than 40 hours per week. This tendency is slightly greater among females. Patients often report daytime sleepiness that impedes their activities and functioning. While work schedules are an important environmental contributor to reduced duration of sleep, the demands of work do not have the same effect on all individuals.

Dr Kenneth Ruzindana, a consultant at Kigali University Teaching Hospital of Kigali (CHUK), notes that lack of enough sleep can be due to insomnia. Insomnia is defined as trouble falling asleep, difficulty staying asleep, or waking up early in the morning and not being able to return to sleep.

He carries on that people with insomnia sleep less or poorly, regardless of having a suitable chance to sleep. The poor sleep may lead to distress functioning during the daytime.

Insomnia symptoms have been linked with an increased risk for suicidal thoughts and behaviours. Some studies have suggested that the association is primarily mediated by underlying depression. Insomnia is also allied with sympathetic nervous system activation, and a number of studies have shown an association between insomnia and elevated cardiovascular risk, including hypertension and myocardial infarction, Ruzindana adds.

Health experts recommend the following hours for sleep depending on one’s age.

Infants (4 to 12 months) require 12 to 16 hours per 24 hours (including naps), toddlers (1 to 2 years) need 11 to 14 hours per 24 hours (including naps).

Yet pre-schoolers (3 to 5 years) need 10 to 13 hours per 24 hours (including naps). For school age (6 to 12 years) require 9 to 12 hours per 24 hours.  Teens (13 to 18 years) require 8 to 10 hours per 24 hours. Adults (18 to 60 years) should have seven or more hours per night.

Habits to improve sleep

Be consistent. Go to bed at the same time each night and get up at the same time each morning, including weekends.

Make sure bedroom is quiet, dark, relaxing, and at a comfortable temperature. Remove electronic devices such as TVs, computers, and smartphones within reach.

Avoid large meals, caffeine, and alcohol before bedtime. Don’t use tobacco. Get some exercise. Being physically active during the day can help one fall asleep easily at night.