Sleep and your day

How does lack of sleep affect your daily life?

Lack of sleep affects your daily life first in your head. You react more slowly, make more mistakes and lose your temper sooner³.

Sleep loss can also cause microsleeps³. A microsleep is a few seconds when the brain switches off without you knowing.

In India the days are long to begin with. A late call with a team abroad. A family function that ends after midnight. Exams in March. Sleep is usually the first thing to give way.

The body pays too, over months and years. Chapter 1 covers weight, blood pressure and immunity. This chapter is about the next day.

Does one bad night of sleep matter?

Yes, one bad night of sleep matters. It changes how you feel and how you drive the next day. You recover if you sleep well the night after, but several short nights in a row stack up³.

After one sleepless night, people in a study felt up to 30% more anxious⁸.

Losing 1–2 hours a night for several nights can affect you as much as going a whole day or two without any sleep³. You may feel you have adjusted. The effect is still there³.

What helps after one short night: a 20-minute nap before 3 pm¹⁰, morning daylight and your usual wake time.

So one bad night is not a disaster. A week of them, during a wedding in the family or a big project at work, needs a few early nights to recover.

How does poor sleep affect work?

Poor sleep affects work by slowing your thinking and adding errors. You can still sit at your desk, but work that needs care, judgement or patience with people suffers first³.

Sleep loss makes problem-solving and decision-making harder³. A simple email takes longer, and the mistake in it is easier to miss.

Patience goes too³. A tired manager snaps in the meeting. A tired shopkeeper is short with a customer.

The cost adds up. In the US, short sleep costs up to $411 billion a year, about 2.28% of the economy⁷.

People who work at night carry this every day. Among nurses on night and rotating shifts in South India, 25.3% reported daytime sleepiness¹¹. If you work nights, Chapter 2 explains how to protect your day sleep.

Is drowsy driving as dangerous as drunk driving?

Drowsy driving can be as dangerous as drunk driving. After 17–19 hours awake, people do as badly on reaction tests as with a blood alcohol level of 0.05%².

Blood alcohol level is the amount of alcohol in your blood. India's legal limit for drivers is 0.03%, which is 30 mg of alcohol in every 100 ml of blood¹². So 17–19 hours awake puts your reactions past the level India allows at the wheel.

Picture a normal day. You wake at 6 am, work, then drive back from a family function after midnight. By then you have been awake 18 hours.

After longer without sleep, people did as badly as with a blood alcohol level of 0.1%².

Each hour of sleep you lose raises your crash risk¹.

Missing just 1–2 hours of sleep nearly doubles the risk. Under 4 hours, it is more than 11 times higher¹.

In a US survey, nearly 1 in 3 drivers said they had driven in the past month so tired they could barely keep their eyes open¹. More than 1 in 5 fatal crashes involve a drowsy driver¹.

India recorded 4,80,583 road accidents and 1,72,890 deaths in 2023⁵. Official records don't list tiredness as a cause, so drowsy driving is probably hidden inside these numbers⁵.

In a survey of 1,217 Indian truck drivers in 10 cities, almost half said they keep driving when tired or sleepy⁶. They drove about 12 hours and 417 km a day⁶.

What should I do if I feel sleepy while driving?

If you feel sleepy while driving, pull over at the first yawn and sleep for 20 minutes in a safe, lit place¹⁰. Nothing else fixes it.

Know the warning signs⁴:

• yawning again and again
• heavy eyelids
• drifting out of your lane
• missing a turn or an exit
• not remembering the last few kilometres

Opening the window or turning up the music doesn't work⁴. Coffee helps for only a few hours⁴. A 20-minute nap helps more than another coffee⁴¹⁰.

Plan long drives around your body. Avoid driving between midnight and 6 am and in the mid-afternoon, and split long trips into parts⁴. On a night drive home for Diwali, share the driving or stop at a lit dhaba for a short nap.

The same rules apply on a two-wheeler. Slow reactions and microsleeps³ are even more dangerous with no doors around you.

Can lack of sleep make you irritable or moody?

Yes, lack of sleep can make you irritable and moody. Without enough sleep, the brain has a harder time keeping feelings in check, so small things annoy you and worries feel bigger³.

Your family may notice before you do.

Deep sleep works like a natural calming system for the mind overnight⁸. Deep sleep is the slow, heavy stage of sleep early in the night (Chapter 1).

In a joint family or a shared flat, tired people clash more. If an argument is building and you slept badly, it is fair to say so and pick the talk up tomorrow.

If low mood and poor sleep keep feeding each other for weeks, Chapter 6 explains the link and where to get help.

Should I exercise if I didn't sleep well?

Yes, you can exercise if you didn't sleep well, but keep it light to moderate. A brisk walk, gentle yoga or an easy swim lifts your energy. Save heavy weights and hard runs for a rested day.

Moderate to vigorous exercise helps you fall asleep faster and wake less often⁹.

Poor sleepers tend to move less the next day⁹, and moving less then makes the next night worse. A short walk helps.

When you are tired, your reactions are slower and you make more mistakes³. That matters with a heavy barbell, on a cricket pitch, or cycling through morning traffic.

Morning exercise outdoors gives you daylight too, which helps your body clock wake up. Chapter 2 explains why.

How do I get through the day after a bad night?

To get through the day after a bad night, get up on time, get daylight, keep moving, and nap for 20 minutes after lunch if you can¹⁰. Don't drive long distances.

Go to bed at your normal time that night, or a little earlier.

A short nap helps more than a long lie-in. Keep it to about 20 minutes and take it before 3 pm¹⁰.

Do your hardest work early in the day, while you are freshest. Leave routine tasks for the afternoon dip.

Eat regular, light meals. A light lunch makes the afternoon easier.

Chapter 2 explains how late is too late for that cup of coffee.

At night, don't try to "catch up" by sleeping at 8 pm and lying awake at 2 am. A normal bedtime, or one a little earlier, brings your sleep back fastest.

How long should a power nap be?

A power nap should be about 20 minutes, never more than 30, and before 3 pm¹⁰. Longer naps reach deep sleep, and you wake up groggy.

A power nap is a short daytime sleep that leaves you more alert without spoiling the night.

Set an alarm for 20 minutes¹⁰. Lie down or lean back in a quiet, dim spot.

Take it early in the afternoon. A nap within 8 hours of bedtime makes falling asleep at night harder¹⁰.

People on night shifts and emergency duties are the exception. A nap of about 90 minutes can suit them before a long shift¹⁰.