Even after sleeping well at night, some people may struggle to stay awake during the day. There are often many underlying causes for this, from biological, psychological, and psychological reasons to even external factors. Hypersomnia , as daytime sleepiness is also called, affects one’s cognitive function and alertness, thus heightening one’s risk of accidents or mistakes. While some causes can be worked with and managed, some triggers may be beyond one’s control.

Common causes of excessive daytime sleepiness
Here are a few common causes of excessive daytime sleepiness:

1. Sleep deprivation
The most common cause is inadequate sleep during the night, leading people to want to take naps during the day.

2. Vitamin B12 deficiency
Recent studies have found that those deficient in vitamin B12 may experience unnatural fatigue or tiredness, which can result in feeling sleepy all the time. B12 affects red blood cell production and cell oxygenation.

3. Mental health issues
Depression, anxiety, or general stress can rob one of their energy and lead to a constant sense of sleepiness during the day.

4. Sleep disorders or other medical conditions
Those who have sleep disorders like sleep apnea, restless legs syndrome, narcolepsy, sleepwalking, and insomnia may all experience excessive daytime sleepiness. Often, the symptoms of these diseases, such as snoring and jerky leg movements, affect sleep quality at night. Apart from these, conditions like nocturnal asthma and hypothyroidism can also result from daytime sleepiness.

All of these factors can be worked with and managed with the help of a doctor. But apart from these, one may also notice that living in certain cities or areas may trigger more daytime sleepiness than others.

External triggers for daytime sleepiness
Here are a few external triggers for daytime sleepiness:

1. Excessive sunlight exposure
Exposure to scorching heat often leads to dehydration and a general sense of drowsiness throughout the day. Sunlight also affects melatonin production, a hormone that aids sound sleep. So, it might be challenging to remain awake and alert if one’s excessively exposed to sunlight.

2. Irregular work schedules
The body needs a routine sleep-wake cycle to feel fully energetic during the day, but people who work rotating shifts or have night work timings may suffer from daytime sleepiness.

3. Blue light exposure
Like sunlight, exposure to blue light emitted by electronic devices like smartphones, tablets, and computers, especially right before bedtime, can lead to poor sleep quality and, as a result, daytime sleepiness the next day.

4. Noise pollution
Exposure to excessive noise at night, whether from traffic, construction, or noisy neighbors, can also interfere with one’s restorative sleep, affect one’s alertness, and impair cognitive function during the day.

5. New family demands
Having a baby or a sudden rise in one’s social demands can often cause daytime sleepiness, as these factors may heighten stress, disrupt nighttime sleep, and alter lifestyles.

6. Poor air quality or ventilation
While this might not seem obvious, the quality of air one inhales every day has a great impact on one’s body. The poorer the air quality, the more susceptible one is to developing respiratory issues. As a result, the body cells may not receive enough oxygen, causing overall drowsiness and impaired daytime functioning. The same result applies to a lack of ventilation.

7. Jet lag
Being jet-lagged can be another trigger for daytime sleepiness since the body’s natural sleep-wake cycle goes for a toss due to changing time zones.